Patent Publication Number: US-10775053-B2

Title: Heating furnace using self-calibration mode

Description:
TECHNICAL FIELD 
     This disclosure relates generally to heating, ventilating, and air conditioning (HVAC) systems, and more specifically to systems and methods for operating a heating system in multiple operation modes. 
     BACKGROUND 
     Heating, ventilation, and air conditioning (HVAC) systems can be used to regulate an environment within an enclosure. Typically, a circulating fan is used to pull air from the enclosure into the HVAC system through ducts and to push the air back into the enclosure through additional ducts after conditioning the air (e.g. heating or cooling the air). For example, a gas furnace, such as a residential gas furnace, is used in a heating system to heat the air. 
     Existing heating systems use two heating stages that are sized for peak periods of the year where maximum heat is required. For example, existing heating systems are typically sized to produce either 100% or 75% of their maximum heat output. During operation, these existing systems are cycled frequently and create high discharge air temperatures that may cause heating related issues such as stratification within a room. It is desirable to provide a heating system that allows for better discharge air temperature control. 
     SUMMARY 
     In one embodiment, the disclosure includes a heating control system comprising an air circulation fan configurable to operate at a plurality of speeds and a heating unit operably coupled to the air circulation fan. The heating unit comprises a plurality of burners and is configurable to operate with less than all of the burners active. The heating control system further comprises a memory operable to store a temperature difference threshold and a temperature map that maps temperatures to speeds of the air circulation fan. The heating control system further comprises a microprocessor operably coupled to the air circulation fan, the heating unit, and the memory. The microprocessor is configured to determine a first speed for the air circulation fan that corresponds with a temperature set point using the temperature map and transmit a first electrical signal to operate the air circulation fan at the first speed and the heating unit in a first configuration with at least one active burner from a plurality of burners where less than all of the burners are active when the heating unit is in the first configuration. The microprocessor is further configured to obtain a first temperature while operating the air circulation fan at the first speed, determine a first temperature difference between the first temperature and the temperature set point, compare the first temperature difference to a temperature difference threshold, and transmit a second electrical signal to transition the air circulation fan from the first speed to a second speed when the first temperature difference is greater than the temperature difference threshold. The microprocessor is further configured to obtain a second temperature while operating the air circulation fan at the second speed, determine a second temperature difference between the second temperature and the temperature set point, compare the second temperature difference to the temperature difference threshold, and update the temperature map to map the second speed to the temperature set point when the second temperature difference is less than the temperature difference threshold. 
     In another embodiment, the disclosure includes a heating control method comprising determining a first speed for an air circulation fan that corresponds with a temperature set point using a temperature map that maps temperatures to speeds of the air circulation fan and operating the air circulation fan at the first speed and a heating unit in a first configuration with at least one active burner from a plurality of burners where less than all of the burners are active when the heating unit is in the first configuration. The method further comprises measuring a first temperature while operating the air circulation fan at the first speed, determining a temperature difference between the first temperature and the temperature set point, comparing the temperature difference to a temperature difference threshold, and updating the temperature map to map the first speed to the first temperature when the temperature difference is greater than the temperature difference threshold. 
     In yet another embodiment, the disclosure includes a heating control method comprising determining a first speed for an air circulation fan that corresponds with a temperature set point using a temperature map that maps temperatures to speeds of the air circulation fan and operating an air circulation fan at the first speed and a heating unit in a first configuration with at least one active burner from a plurality of burners where less than all of the burners are active when the heating unit is in the first configuration. The method further comprises measuring a first temperature while operating the air circulation fan at the first speed, determining a first temperature difference between the first temperature and the temperature set point, comparing the first temperature difference to a temperature difference threshold, and transitioning the air circulation fan from the first speed to a second speed when the first temperature difference is greater than the temperature difference threshold. The method further comprises measuring a second temperature while operating the air circulation fan at the second speed, determining a second temperature difference between the second temperature and the temperature set point, comparing the second temperature difference to the temperature difference threshold, and updating the temperature map to map the second speed to the temperature set point when the second temperature difference is less than the temperature difference threshold. 
     The present embodiment presents several technical advantages. The present embodiment discloses a heating system that is reconfigurable to provide both coarse and fine temperature adjustments and control. The heating system is configured to employ a segmented gas manifold, which enables the heating system to be reconfigured to provide a plurality of discrete heat output levels. The heating system is also configured to allow a variable speed air circulation fan to operate over a wider operating range to finely adjust the heat output of the heating system. The heating system may also be configured to employ the segmented gas manifold with a constant burner which allows a pulsed burner to rapidly toggle on and off to adjust the heat output of the heating system. The heating system may be configured to generate significantly less heat output than existing heating systems, which increases the overall range of temperatures and heat output that can be provided by the heating system. 
     Certain embodiments of the present disclosure may include some, all, or none of these advantages. These advantages and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
         FIG. 1  is a schematic diagram of an embodiment of a heating system; 
         FIG. 2  is a schematic diagram of an embodiment of a portion of a heating unit for a heating system; 
         FIG. 3  is a schematic diagram of another embodiment of a portion of a heating unit for a heating system; 
         FIG. 4  is a flowchart of an embodiment of a heating control method for operating a heating system in a discharge air heating control mode; 
         FIG. 5  is a flowchart of an embodiment of a heating control method for operating a heating system in an anti-stratification mode; 
         FIG. 6  is a flowchart of an embodiment of a heating control method for operating a heating system in an energy saving mode; 
         FIG. 7  is a graph of an embodiment of operating a heating system in an energy saving mode; 
         FIG. 8  is a flowchart of an embodiment of a heating control method for operating a heating system in a rapid response heat control mode; 
         FIG. 9  is a graph of an embodiment of operating a heating system in a rapid response heat control mode; 
         FIG. 10  is a flowchart of an embodiment of a heating control method for operating a heating system in a self-calibration mode; 
         FIG. 11  is a flowchart of another embodiment of a heating control method for operating a heating system in a self-calibration mode; 
         FIG. 12  is a graph of an embodiment of operating a heating system in a self-calibration mode; 
         FIG. 13  is a flowchart of an embodiment of a heating control method for operating a heating system in an auto heating commissioning mode; 
         FIG. 14  is a flowchart of another embodiment of a heating control method for operating a heating system in an auto heating commissioning mode; and 
         FIG. 15  is a flowchart of an embodiment of a heating control method for operating a heating system in a gas pulse modulation temperature control mode. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are various embodiments for providing multi-stage heating control for a heating system to provide improved discharge air temperature control. Multi-stage heating control allows a heating system to determine and reconfigure the heating system to control the discharge air temperature using a temperature map. Using multi-stage heating control, the heating system can adjust the speed of an air circulation fan (ACF) to fine-tune the discharge air temperature and reconfigure itself to match a heating load based on load conditions. 
     In one embodiment, a heating system employing multi-stage heating control may be configured in a discharge air heating control mode to adjust a discharge or supply air temperature or temperature rise. The heating system is reconfigurable and may employ a variable speed ACF to provide a broad range of discharge air temperature or temperature rise outputs. Existing heating systems are unable to provide a wide range of operating speeds for the ACF due to overheating issues that occur when the ACF speed is reduced. 
     The heating system may also be configured in an anti-stratification mode to reduce temperature rise. The ability to reduce the temperature rise allows the heating system to resolve or avoid stratification within a room. Stratification is the condition where heat sits primarily in an upper portion of a room (e.g. near the ceiling) and does not disperse properly throughout the room. The heating system is configured to use air temperature sensors to detect conditions which may cause stratification and to adjust the discharge air temperature to reduce a temperature rise for a room in response to detecting these conditions. Reducing the temperature rise allows the heated air to diffuse better within the room. 
     The heating system may also be configured in an energy saving mode to operate in a low-energy mode by default, to transition to a higher-energy mode when necessary, and to transition from the higher-energy mode back to a low-energy mode whenever possible. Operating in the low-energy mode allows the heating system to operate in an energy saving state which delivers minimal temperature increase and allows the ACF to stay at a low speed to gradually heat up a room over a longer period of time. The heating system is configured to adjust the speed of the ACF when additional heat is required and then to adjust the speed back to a low-energy mode when the additional heat is no longer required. 
     The heating system may also be configured to operate in a rapid response heat control mode to quickly heat up a room without exceeding or overshooting a temperature set point. The heating system is configured to monitor and adjust discharge air temperature as the heating system rapidly provides heat to a room. The heating system is configured to provide enough heat to reach a target temperature set point without overheating and exceeding the temperature set point. As heat is provided to the room, the discharge air temperature or temperature rise is gradually reduced as the room air temperature approaches the temperature set point. 
     The heating system may also be configured to operate in a self-calibration mode to update default settings or temperature maps for the heating system based on environmental conditions. The heating system is configured to test and update factory default settings in a temperature map using information that is acquired from a job site. 
     The heating system may also be configured to operate in an auto heat commissioning mode to monitor smoke output while burning lubricants. The heating system is configured to adjust the heating temperatures used for burning lubricants during maintenance to control the smoke output of the heating system. Providing better temperature control of the heating temperatures for burning the lubricants may reduce the time for commissioning a heating system and may limit the formation of smoke when replacing a gas heat exchanger. 
     The heating system may also be configured to operate in a gas pulse modulation temperature control mode to adjust a discharge air temperature or temperature rise using a modulated pulsed burner. The heating system is configured to employ a constant burner which allows the heating system to remain lit and active with a modulated pulsed burner with an adjustable duty cycle. The duty cycle of the pulsed burner is adjusted to control the discharge air temperature of the heating system. 
       FIG. 1  is a schematic diagram of an embodiment of a heating system  100 . An example of a heating system  100  includes, but is not limited to, a gas fired combustible fuel-air burning furnace. The heating system  100  may be for a residence or for a commercial building (e.g. a residential or commercial unit), for example, a rooftop unit (RTU). The heating system  100  may be utilized in single or multiple zoned systems. 
     The heating system  100  comprises an ACF  120 , a heating unit  122 , a return air temperature sensor  138 , a discharge air sensor (DAS)  128 , a room air temperature sensor  136 , a smoke sensor  162 , a thermostat  132 , a furnace controller  102 , and a memory  142 . Portions of the heating system  100  may be contained within a cabinet  104 . In some embodiments, the furnace controller  102  may be included within the cabinet  104 . The heating system  100  may be configured as shown or in any other suitable configuration. The heating system  100  is configured to generate heat and to provide the generated heat to a conditioned space or room  158  to control the temperature within the room  158 . The heating system  100  is configured to employ multi-stage heating control which allows the heating system  100  to configure itself to control the discharge air temperature and to adjust the speed of the ACF  120  to fine-tine the discharge air temperature. In one embodiment, the heating system  100  may be configured to achieve a five to one (5:1) turndown ratio or a seven to one (7:1) turndown ratio. A turndown ratio is the operation range of the heating system  100 , for example, the ratio of the maximum output to the minimum output. Alternatively, the heating system  100  may be configured to achieve any other turndown ratio as would be appreciated by one of ordinary skill in the art upon viewing this disclosure. 
     The ACF  120  is a variable speed unit blower that is operably coupled to the furnace controller  102 . The furnace controller  102  may adjust the speed of the ACF  120  to control the discharge air temperature or temperature rise of the heating system  100 . The ACF  120  may be configured to operate at 10%, 25%, 50%, 75%, 100%, or any other suitable percentage of the maximum speed of the ACF  120 . The ACF  120  is configured to circulate air between the cabinet  104  and the room  158 . The ACF  120  is configured to pull return air  156  from the room  158 , to communicate the return air  156  to the heating unit  122  to heat up the air, and to communicate the heated air as supply or discharge air  154  to the room  158 . 
     The heating unit  122  comprises a burner assembly  124  having a plurality of burners  118 , a heat exchanger  110 , a combustion air inducer or combustion air blower (CAB)  106 , a first gas valve  126 , a second gas valve  130 , and a gas supply  134 . In one embodiment, the heating unit  122  is a single furnace. The heating unit  122  is configured to generate heat for heating air that is communicated from the ACF  120  to the room  158 . The heating unit  122  is configurable between a plurality of configurations to adjust the amount of heat generated by the heating unit  122 . For example, the heating unit  122  may be configured to generate 7%, 10%, 25% 53%, 64%, 75%, 100%, or any other suitable percentage of the maximum heat output of the heating unit  122 . 
     The burner assembly  124  comprises a gas manifold  160  that includes a plug  162  disposed within the gas manifold  160  that separates the gas manifold  160  into segments and partitions the burners  118  into subsets. For example, the plug  162  is disposed within the gas manifold  160  and configured to form a first segment of the gas manifold  160  for a first set of burners  114  and a second segment of the gas manifold  160  for a second set of burners  116 . The plug  162  is configured to disallow gas communication between segments (e.g. the first segment and the second segment) of the gas manifold  160 . 
     Burners  118  are configured for burning a combustible fuel-air mixture (e.g. gas-air mixture) and to provide a combustion product to the heat exchanger  110 . The burners  118  are separated into subsets of burners  118  and each set of burners  118  is connected to the fuel source or gas supply  134  via a gas valve. The ratio of burners  118  to gas valves can be adjusted to change the heat output of the heating unit  122  for various configurations of the heating unit  122 . For example, a first set of burners  114  is connected to the gas supply  134  via the first gas valve  126  and a second set of burners  116  is connected to the gas supply  134  via the second gas valve  130 . The first set of burners  114  and the second set of burners  116  may each comprise any suitable number of burners  118 . The number of burners  118  in the first set of burners  114  and the second set of burners  116  may be the same or different. The burners  118  may be configured to stay active (i.e. on) during operation or to pulse (i.e. toggle between on and off) during operation. A burner  118  configured to stay active during operation is referred to as a constant burner  118  and a burner  118  configured to pulse during operation is referred to as a pulsed burner  118 . A pulsed burner  118  has an adjustable duty cycle so that the percentage of the time period that the pulsed burner  118  is active is adjustable. The pulsed burner  118  is configured to be toggled or modulated using pulse width modulation (PWM). For example, a pulsed burner  118  may be modulated by the furnace controller  102  using pulse width modulation. 
     An example of the first gas valve  126  and the second gas valve  130  is a two-stage valve. The first gas valve  126  and the second gas valve  130  are configured to allow or disallow gas communication between the gas supply  134  and segments of the gas manifold  160 . For example, the first gas valve  126  and the second gas valve  130  may be operable between an off configuration that substantially blocks gas flow between the gas supply  134  and the gas manifold  160 , a low-fire rate configuration that allows a first pressure or flow rate of gas to be communicated to the burners  118 , and a high-fire rate configuration that allows a second pressure or flow rate of gas that is higher than the first pressure to be communicated to the burners  118 . The gas supply  134  is configured to store and provide a fuel or gas for the heating unit  122 . The gas supply  134  is configured to store and provide any suitable combustible fuel or gas as would be appreciated by one of ordinary skill in the art upon viewing this disclosure. 
     The heat exchanger  110  comprises a plurality of tubes  112 , for example, a tube for each burner  118 . The heat exchanger  110  is configured to receive the combustion product from the burner assembly  124  and to use the combustion product to heat air that is blown across the heat exchanger  110  by the ACF  120 . The CAB  106  is configured to supply combustion air to the burner assembly  124  (i.e. the burners  118 ) using an induced draft and is also used to exhaust waste products of combustion from the heating system  100  through a vent  108 . In an embodiment, the CAB  106  is operable between two speed settings, for example, a low speed that corresponds with the low-fire mode of operation for the burners  118  and a high speed that corresponds with the high-fire mode of operation for the burners  118 . The CAB  106  is configured such that the low speed and the high speed correspond to the low-fire gas rate and the high-fire gas rate, respectively, to provide gas-fuel-mixture for the low-fire and high-fire modes of the heat exchanger  110 . In one embodiment, the air-fuel mixture is substantially constant through the various heating unit  122  configurations. 
     The return air temperature senor  138  is configured to determine a return air temperature for the heating system  100 . For example, the return air temperature sensor  138  may be a temperature sensor configured to determine the ambient temperature of air that is returned to or entering the heating system  100  and to provide the temperature data to the furnace controller  102 . In one embodiment, the return air temperature sensor  138  is located in the cabinet  104 . Alternatively, the return air temperature sensor  138  may be positioned in other locations to measure the return air temperature for the heating system  100 . For example, the return air temperature sensor  138  may be positioned in a duct between the cabinet  104  and the room  158 . 
     An example of the DAS  128  includes, but is not limited to, a 10K Negative Temperature Coefficient (NTC) sensor. The DAS  128  is configured to determine a discharge or supply air temperature of the heating system  100 . For example, the DAS  128  may be a temperature sensor configured to determine the ambient temperature of air that is discharged from the heating system  100  and to provide the temperature data to the furnace controller  102 . In one embodiment, the DAS  128  is located in the cabinet  104 . Alternatively, the DAS  128  may be positioned in other locations to measure the discharge air temperature of the heating system  100 . For example, the DAS  128  may be positioned in a duct between the cabinet  104  and the room  158 . 
     The room air temperature sensor  136  is configured to determine an air temperature for the room  158 . For example, the room air temperature sensor  136  may be a temperature sensor configured to determine the ambient temperature of air of the room  158  and to provide the temperature data to the furnace controller  102 . The room air temperature sensor  136  may be located anywhere within the room  158 . The thermostat  132  may be a two-stage thermostat or any suitable thermostat employed in an HVAC system to generate heating calls based on a temperature setting as would be appreciated by one of ordinary skill in the art upon viewing this disclosure. The thermostat  132  is configured to allow a user to input a desired temperature or temperature set point for a designated area or zone such as the room  158 . 
     An example of the smoke sensor  162  includes, but is not limited to, a carbon dioxide (CO  2 ) sensor. The smoke sensor  162  is operably coupled to a duct between the cabinet  104  and the room  158  or to the vent  108 . The smoke sensor  162  is configured to measure the amount of smoke in the air and to output a smoke output measurement based on the amount of smoke in the air. 
     The memory  142  may comprise one or more disks, tape drivers, or solid-state drives and may be used as an over-flow data storage device, to store programs when such programs are selected for execution, and to store instructions and data that are read during program execution. The memory  142  may be volatile or non-volatile and may comprise read-only memory (ROM), random-access memory (RAM), ternary content-addressable memory (TCAM), dynamic random-access memory (DRAM), and static random-access memory (SRAM). The memory  142  is operable to store a temperature map  144 , temperature rise thresholds  146 , temperature thresholds  148 , smoke output thresholds  150 , and temperature difference thresholds  152 , among other information and data used to support the various modes of operation described herein. The temperature map  144  may comprise predetermined mappings between any combination of temperature, speeds of the ACF  120 , configurations of the heating unit  122 , duty cycles for pulsed burners  118 , and smoke output measurements. For example, the temperature map  144  may map a first temperature to a first speed of the ACF  120 , a second temperature to a second speed of the ACF  120 , and so on. As another example, the temperature map  144  may map a first temperature to a first configuration of the heating unit  122 , a second temperature to a second configuration of the heating unit  122 , and so on. Additional details and examples of the temperature map  144  are described later in Tables 1-5. The temperature map  144  may be configured with any predetermined mapping or combination of mappings as would be appreciated by one of ordinary skill in the art upon viewing this disclosure. The temperature rise threshold  146 , the temperature threshold  148 , the smoke output threshold  150 , and the temperature difference threshold  152  are dynamically determined or predetermined thresholds that may be used for calculations with respect to a temperature rise, temperature, smoke output, and temperature differences, respectively. 
     The furnace controller  102  may be implemented as one or more central processing unit (CPU) chips, logic units, cores (e.g. as a multi-core processor), field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), or digital signal processors (DSPs). The furnace controller  102  is operably coupled to and in signal communication with the memory  142 , the thermostat  132 , the room air temperature sensor  136 , the return air temperature sensor  138 , the DAS  128 , the smoke sensor  162 , the first gas valve  126 , the second gas valve  130 , the ACF  120 , and the CAB  106  via one or more input/output (I/O) ports. The furnace controller  102  is configured to receive and transmit electrical signals among one or more of the memory  142 , the thermostat  132 , the room air temperature sensor  136 , the return air temperature sensor  138 , the DAS  128 , the smoke sensor  162 , the first gas valve  126 , the second gas valve  130 , the ACF  120 , and the CAB  106 . The electrical signals may be used to send and receive data (e.g. temperature data) or to operate and control one or more components of the heating system  100 . For example, the furnace controller  102  may transmit electrical signals to operate the ACF  120  and to adjust the speed of the ACF  120 . The furnace controller  102  may be operably coupled to one or more other devices or pieces of HVAC equipment (not shown). The furnace controller  102  is configured to process data and may be implemented in hardware or software. 
     In  FIG. 1 , the heating control instructions  140  for the heating system  100  are implemented as instructions (e.g. software code or firmware) stored in the furnace controller  102 . Alternatively, the heating control instructions  102  may be implemented as instructions stored in the memory  142 . The inclusion of the heating control instructions  140  provides an improvement to the functionality of the heating system  100 , which effects a transformation of the heating system  100  to a different state. The heating control instructions  140  are implemented by the furnace controller  102  to execute instructions for implementing various modes of operation for the heating system  100 . 
     The heating control instructions  140  comprise instructions to operate the heating system  100  in a discharge air heating control mode to adjust a discharge air temperature or temperature rise by adjusting the speed of the ACF  120  and/or the configuration of the heating unit  122 . Additional details and an example are discussed in  FIG. 4 . 
     The heating control instructions  140  also comprise instructions to operate the heating system  100  in an anti-stratification mode to reduce temperature rise for resolving or avoiding stratification within a room. The heating control instruction  140  configure the heating system  100  to use the DAS  128  or the return air sensor  138  and the room air temperature sensor  136  to detect conditions which may cause stratification and to adjust the discharge air temperature by adjusting the speed of the ACF  120  and/or the configuration of the heating unit  122  in response to detecting these conditions. Additional details and an example are discussed in  FIG. 5 . 
     The heating control instructions  140  also comprises instructions to operate the heating system  100  in an energy saving mode to operate in a low-energy mode by default, to transition to a higher-energy mode when necessary, and to transition from the higher-energy mode to the low energy state whenever possible. Additional details and examples are discussed in  FIGS. 6 and 7 . 
     The heating control instructions  140  also comprise instructions to operate the heating system  100  in a rapid response heat control mode to quickly heat up a room without exceeding a temperature set point. The heating control instructions  140  configure the heating system  100  to monitor and adjust discharge air temperature by gradually adjusting the speed of the ACF  120  and/or the configuration of the heating unit  122  as the heating system  100  rapidly provides heat to reach a target temperature set point without overheating and passing the temperature set point. Additional details and examples are discussed in  FIGS. 8 and 9 . 
     The heating control instructions  140  also comprise instructions to operate the heating system  100  in a self-calibration mode to update temperature maps  144  for the heating system  100  based on environmental conditions. The heating control instructions  140  configure the heating system  100  to test and modify factory default settings or mappings in the temperature map  144  using information that is acquired from the location of the heating system  100 . Additional details and examples are discussed in  FIGS. 10-12 . 
     The heating control instructions  140  also comprise instructions to operate the heating system  100  in an auto heat commissioning mode to monitor smoke output while burning lubricants. The heating control instructions  140  configures the heating system  100  to adjust temperatures used for burning lubricants during maintenance by adjusting the speed of the ACF  120  and/or the configuration of the heating unit  122  to control the smoke output of the heating system. Additional details and examples are discussed in  FIGS. 13 and 14 . 
     The heating control instructions  140  also comprises instructions for operating the heating system  100  in a gas pulse modulation temperature control mode to adjust a discharge air temperature or temperature rise using a pulsed burner  118 . The heating control instructions  140  configures the heating system  100  to employ a constant burner  118  which allows the heating system  100  to remain lit and active with a modulated pulsed burner  118  with an adjustable duty cycle that is used to adjust and control the discharge air temperature. Additional details and an example are discussed in  FIG. 15 . 
     Additional information about the heating system  100  is described in U.S. patent application Ser. No. 14/976,354 entitled, “MULTIPLE STAGE MODULATING GAS FIRED HEAT EXCHANGER,” by Steven Schneider, et al., filed on Dec. 21, 2015 and U.S. patent application Ser. No. 14/976,485 entitled, “FIELD CONVERSION OF A HEATING SYSTEM TO A MULTIPLE STAGE MODULATING GAS FIRED HEAT EXCHANGER,” by Steven Schneider, et al., filed on Dec. 21, 2015, which are both hereby incorporated by reference as if reproduced in their entirety. 
       FIG. 2  is a schematic diagram of an embodiment of a portion  200  of a heating unit  122  for a heating system  100 . The portion  200  of the heating unit  122  is reconfigurable between a plurality of configurations to adjust the amount of heat generated and outputted by the heating unit  122 . The amount of heat generated by the heating unit  122  is based on the number of burners  118  that are active and the amount of pressure or flow rate of the gas valves that are operably coupled to the active burners  118 . 
     The portion  200  comprises the gas supply  134 , the CAB  106 , the first gas valve  126 , the second gas valve  130 , and the burner assembly  124  that comprises the gas manifold  160 , the plug  162 , and the burners  118 . The plug  162  is disposed within the gas manifold  160  and configured to form a first segment of the gas manifold  160  for a first set of burners  114  and a second segment of the gas manifold  160  for a second set of burners  116 . The plug  162  is configured to disallow gas communication between segments of the gas manifold  160 . In another embodiment, the gas manifold  160  may comprise one or more additional plugs (not shown). In such an embodiment, the gas manifold  160  may be partitioned into more than two segments and may support more than two subsets of burners  118 . 
     In  FIG. 2 , the first set of burners  114  has two burners  118  and the second set of burners  116  has five burners  118 . In other embodiments, the first set of burners  114  and the second set of burners  116  may comprise any suitable number of burners  118  to achieve desired operations. The number of burners  118  in the first set of burners  114  and the second set of burners  116  may be the same or different. The first set of burners  114  and the second set of burners  116  are configured to operate independently. For example, the burner assembly  124  may be configured such that both the first set of burners  114  and the second set of burners  116  are active, one of the first set of burners  114  or the second set of burners  116  is inactive, or both the first set of burners  114  and the second set of burners  116  is inactive. 
     A burner  118  is active (i.e. on) when the burner  118  is in a low-fire mode or in a high-fire mode. When the burner  118  is in the low-fire mode, the respective gas valve is configured to operate at the low-fire rate and the CAB  106  is configured to operate at a low speed. When the burner  118  is in the high-fire mode, the respective gas valve is configured to operate at the high-fire rate and the CAB  106  is at the configured to operate at a high speed. A burner  118  is inactive when the burner  118  is in an off state or mode. When the burner  118  is in the off mode, the respective gas valve is configured to disallow gas communication to the burner  118 . 
       FIG. 3  is a schematic diagram of another embodiment of a portion  300  of a heating unit  122  for a heating system  100 . The portion  300  comprises the gas supply  134 , the CAB  106 , the first gas valve  126 , the second gas valve  130 , and the burner assembly  124  that comprises the gas manifold  160 , the plug  162 , and the burners  118 . The portion  300  of the heating unit  122  is configured to adjust the amount of heat generated and outputted by the heating unit  122  using one or more pulsed burners  118 . The amount of heat generated by the heating unit  122  is based on the number of burners  118  that are active, the amount of pressure or flow rate of the gas valves that are operably coupled to the active burners  118 , and the percentage of a time period that the pulsed burners  118  are active (i.e. the duty cycle of the pulsed burners  118 ). 
     In  FIG. 3 , the burner assembly  124  is configured such that the first set of burners  114  has one burner  118  and the second set of burners  116  has ten burners  118 . The first set of burners  114  and the second set of burners  118  may be configured to operate either as constant burners  118  or pulsed burners  118 . A burner  118  is a constant burner  118  when the burner  118  is configured to remain active, for example, in either the low-fire mode or the high-fire mode during operating. A burner  118  is a pulsed burner  118  when the burner  118  is configured to toggle between being active and inactive, for example, between the low-fire mode or the high-fire mode and the off mode. The percentage of a time period that the pulsed burners  118  are active (i.e. the duty cycle of the pulsed burners  118 ) is adjustable. The duty cycle of the pulsed burner  118  may be modulated or varied to generate different amounts of heat. The amount of heat generated by the pulsed burner  118  is proportional to the duty cycle of the pulsed burner  118 , for example, a low duty cycle (e.g. less than 50%) generates less heat than a high duty cycle (e.g. greater than 50%). Pulsed burners  118  may be toggled or modulated by the furnace controller  102  using pulse width modulation or any other suitable modulation technique as would be appreciated by one of ordinary skill in the art upon viewing this disclosure. 
     In one embodiment, the first set of burners  114  are configured as constant burners and the second set of burners  116  are configured as pulsed burners  118 . The first set of burners  114  is configured to remain active during operation. Keeping the first set of burners  114  in an active mode during operation allows the second set of burners  116  to operate as pulsed burners  118  and to toggle rapidly between an active and inactive mode without the typical delays associated with activating burners  118 . For example, the heating system  100  can bypass the initialization process for turning on the heating system  100 . The second set of burners  116  is configured to be modulated by the furnace controller  102  to adjust the amount of heat output. 
     Tables 1-5 illustrate various combinations of parameters and mappings between the parameters that may be used in a temperature map  144 . Tables 1-5 are not intended to be limiting and are provided for illustrative purposes only. Tables 1-5 provide examples of temperature maps  144  that may be employed by the furnace controller  102  to operate the heating system  100  in various modes of operation such as the methods described in  FIGS. 4-6, 8, 10, 11, and 13-15 . The usage of a temperature map  144  is described in more detail later with respect to the methods described in  FIGS. 4-6, 8, 10, 11, and 13-15 . 
     Table 1 is one embodiment of a temperature map  144  for a heating system  100 . Table 1 illustrates a temperature map  144  that may be used to adjust the speed of the ACF  120  to control temperature rise and temperature of the supply air. The temperature map  144  provides a mapping among the heat output of the heating unit  122  in terms of the percentage of the maximum heat input, the speed of the ACF  120  in cubic feet per minute (CFM), the temperature rise, and the temperature of the supply air. Table 1 illustrates that with a constant heat output (e.g. 64%) from the heating unit  122  the speed of the ACF  120  can be varied to adjust the temperature rise and the temperature of the supply air. As the speed of the ACF  120  increases, the temperature rise decreases and the temperature of the supply air decreases. The furnace controller  102  may use Table 1 to increase the speed of the ACF  120  to reduce the amount of heat that is provided by the heating system  100 . As the speed of the ACF  120  decreases, the temperature rise increases and the temperature of the supply air increases. The furnace controller  102  may use Table 1 to decrease the speed of the ACF  120  to increase the amount of heat that is provided by the heating system  100 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 An embodiment of a temperature map 144 for a heating system 100 
               
            
           
           
               
               
               
               
               
            
               
                   
                 % Input 
                 CFM 
                 Temp Rise 
                 Supply Air 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                   
                 64% 
                 4000 
                 28 
                 93 
               
               
                   
                 64% 
                 3600 
                 32 
                 97 
               
               
                   
                 64% 
                 3300 
                 34 
                 99 
               
               
                   
                 64% 
                 3250 
                 35 
                 100 
               
               
                   
                 64% 
                 3200 
                 36 
                 101 
               
               
                   
                   
               
            
           
         
       
     
     Table 2 is one embodiment of temperature map  144  with four heating unit  122  configurations. Table 2 illustrates a temperature map  144  that may be used to adjust the number of active burners  118  and the operating mode (e.g. low-fire rate or high-fire rate) of the gas valves coupled to the active burners  118  in the heating unit  122  to control the amount of heat generated and outputted by the heating system  100 . The temperature map  144  provides a mapping among four heat stages or configurations of the heating unit  122  (e.g. heat stages 1-4), the heat output of the heating unit  122  in terms of the percentage of the maximum heat input, the operation mode (e.g. low speed or high speed) of the CAB  106 , the operation mode (e.g. low-fire rate or high-fire rate) of the first gas valve  126 , and the operation mode (e.g. low-fire rate or high-fire rate) of the second gas valve  130 . The first gas valve  126  and the second gas valve  130  may each be operably coupled to any suitable number of burners  118 . When the heating unit  122  is in a first configuration (e.g. heat stage 1), the CAB  106  is configured to operate at a low speed, the first gas valve  126  is configured to operate at a low-fire rate, and the second gas valve  130  is inactive. In the first configuration, the heating unit  122  is configured to output about 7% of the maximum heat input. In the first configuration, the heating unit  122  uses the least amount of energy with respect to the other configurations to produce a heat output that is less than the maximum achievable heat output. When the heating unit  122  is in a second configuration (e.g. heat stage 2), the CAB  106  is configured to operate at a high speed, the first gas valve  126  is configured to operate at a high-fire rate, and the second gas valve  130  is inactive. In the second configuration, the heating unit  122  is configured to output about 9% of the maximum heat input. In the second configuration, the heating unit  122  uses more energy than the first configuration by increasing the pressure of the first gas valve  126 . The increased pressure of the first gas valve  126  allows the heating unit  122  to provide a heat output that is greater than the heat output of the first configuration, but is still less than the maximum achievable heat output. When the heating unit  122  is in a third configuration (e.g. heat stage 3), the CAB  106  is configured to operate at a low speed and the first gas valve  126  and the second gas valve  130  are configured to operate at a low-fire rate. In the third configuration, the heating unit  122  is configured to output about 75% of the maximum heat input. In the third configuration, the heating unit  122  uses more energy than the second configuration, but still uses less energy than is required to achieve the maximum achievable heat output. In an another embodiment, the third configuration may be configured to output any other percentage of the maximum heat input that is greater than the second configuration and less than the maximum achievable heat output. In yet another embodiment, one or more additional configuration may exist between the second configuration and the third configuration to provide more configurations to more gradually adjust the heat output of the heating unit  122 . When the heating unit  122  is in a fourth configuration (e.g. heat stage 4), the CAB  106  is configured to operate at a high speed and the first gas valve  126  and the second gas valve  130  are configured to operate at a high-fire rate. In the fourth configuration the heating unit  122  is configured to output about 100% of the maximum heat input. In the fourth configuration, the heating unit  122  uses the most amount of energy with respect to the other configurations to provide the maximum achievable heat output. 
     Table 2 illustrates that the supply air temperature or temperature rise increases when the CAB  106  transitions from operating at a low speed to operating at a high speed and a gas valve transitions from operating at a low-fire rate to operating at a high-fire rate. Using a temperature map  144  like Table 2, the furnace controller  102  may reconfiguring the heating unit  122  to use more energy by operating the CAB  106  at a high speed and operating the gas valve at a high-fire rate allows the heating unit  122  to generate and output more heat. The supply air temperature or temperature rise also increases when a gas valve (e.g. the second gas valve  130 ) transitions from being inactive to active, for example, from an off mode to a low-fire rate or to a high-fire rate. Using a temperature map  144  like Table 2, the furnace controller  102  may reconfiguring the heating unit  122  to use less energy by operating the CAB  106  at a low speed and operating the gas valve at a low-fire rate allows the heating unit  122  to generate and output less heat. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 An embodiment of a temperature map 144 with 
               
               
                 four heating unit 122 configurations 
               
            
           
           
               
               
               
               
               
            
               
                 Heat stage 
                 % of Input 
                 CAB 
                 GV1 
                 GV2 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 1 
                 7% 
                 Low 
                 Low 
                 Off 
               
               
                 2 
                 9% 
                 High 
                 High 
                 Off 
               
               
                 3 
                 75%  
                 Low 
                 Low 
                 Low 
               
               
                 4 
                 100%  
                 High 
                 High 
                 High 
               
               
                   
               
            
           
         
       
     
     Table 3 is one embodiment of a temperature map  144  with six heating unit  122  configurations. Table 3 illustrates that increasing the number of configurations of the heating unit  122  provides more heat output levels to more finely control a room temperature. Table 3 illustrates a temperature map  144  that can be used to adjust the number of active burners  118  and the operating mode of the gas valve operably coupled to active burners  118  to control the heat output of the heating unit  122 . The temperature map  144  provides a mapping among six heat stages or configurations of the heating unit  122  (e.g. heat stages 1-6), the heat output of the heating unit  122  in terms of the percentage of the maximum heat input, the operation mode (e.g. low speed or high speed) of the CAB  106 , the operation mode (e.g. low-fire rate or high-fire rate) of the first gas valve  126 , and the operation mode (e.g. low-fire rate or high-fire rate) of the second gas valve  130 . In Table 3, the first gas valve  126  is operably coupled to two burners  118  and the second gas valve  130  is operably coupled to five burners  118 . The number of burners  118  that are operably coupled to the first gas valve  126  and the second gas valve  130  may be adjusted to vary the amount of energy that is used and the amount of heat that is generated. For example, increasing the number of burners  118  that are operably coupled to the first gas valve  126  will increase the amount of energy that is used and increase the heat output of the heating unit  122  when the first gas valve  126  is active. 
     When the heating unit  122  is in a first configuration (e.g. heat stage 1), the CAB  106  is configured to operate at a low speed, the first gas valve  126  is configured to operate at a low-fire rate, and the second gas valve  130  is inactive. In the first configuration, the heating unit  122  is configured to output about 21% of the maximum heat input. In the first configuration, the heating unit  122  uses the least amount of energy with respect to the other configurations by operating the CAB  106  at the low speed and using the least amount of active burners  118 . When the heating unit  122  is in a second configuration (e.g. heat stage 2), the CAB  106  is configured to operate at a high speed, the first gas valve  126  is configured to operate at a high-fire rate, and the second gas valve  130  is inactive. In the second configuration, the heating unit  122  is configured to output about 29% of the maximum heat input. In the second configuration, the heating unit  122  uses more heat than the first configuration by increasing the speed of the CAB  106  and the fire rate of the first gas valve  126  that is operably coupled to the active burners  118 . When the heating unit  122  is in a third configuration (e.g. heat stage 3), the CAB  106  is configured to operate at a low speed, the first gas valve  126  is inactive, and the second gas valve  130  is configured to operate at a low-fire rate. In the third configuration, the heating unit  122  is configured to output about 53% of the maximum heat input. In the third configuration, the heating unit  122  uses more energy and provides a higher heat output than the second configuration by switching from the first gas valve  126  to the second gas valve  130  which increases the number of burners  118  that are active. In this example, the number of active burners  118  increases from two to five. When the heating unit  122  is in a fourth configuration (e.g. heat stage 4), the CAB  106  is configured to operate at a high speed, the first gas valve  126  is inactive, and the second gas valve  130  is configured to operate at a high-fire rate. In the fourth configuration, the heating unit  122  is configured to output about 71% of the maximum heat input. In the fourth configuration, the heating unit  122  uses more energy and provides a higher heat output than the third configuration by increasing the speed of the CAB  106  and the flow rate of the second gas valve  130 . When the heating unit  122  is in a fifth configuration (e.g. heat stage 5), the CAB  106  is configured to operate at a low speed and the first gas valve  126  and the second gas valve  130  are configured to operate at a low-fire rate. In the fifth configuration, the heating unit  122  is configured to output about 75% of the maximum heat input. In the fifth configuration, the heating unit uses more energy than the fourth configuration, but still uses less energy than required to achieve the maximum achievable heat output by activating both the first gas valve  126  and the second gas valve  130  which activates all of the burners  118 . When the heating unit  122  is in a sixth configuration (e.g. heat stage 6), the CAB  106  is configured to operate at a high speed and the first gas valve  126  and the second gas valve  130  are configured to operate at a high-fire rate. In the sixth configuration, the heating unit  122  is configured to output about 100% of the maximum heat input. In the sixth configuration, the heating unit  122  is configured to use the most amount of energy with respect to the other configurations to provide the maximum achievable heat output. The heating unit  122  increases the heat output from the fifth configuration by operating the CAB  106  at a high speed and operating both the first gas valve  126  and the second gas valve  130  at a high-flow rate which activates all of the burners  118  at a high-fire rate. 
     Using a temperature map  144  like Table 3, the furnace controller  102  may reconfigure the number of active burners  118  by activating the first gas valve  126  and/or the second gas valve  130  and the operating mode of the active burners  118  to control the heat output of the heating unit  122 . 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 An embodiment of a temperature map 144 with six heating unit 122 
               
               
                 configurations 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                 Heat  
                 % of  
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 stage 
                 Input 
                 CAB 
                 GV1 
                 GV1 
                 GV2 
                 GV2 
                 GV2 
                 GV2 
                 GV2 
               
               
                   
               
               
                 1 
                 21% 
                 Low 
                 Low 
                 Low 
                 Off 
                 Off 
                 Off 
                 Off 
                 Off 
               
               
                 2 
                 29% 
                 High 
                 High 
                 High 
                 Off 
                 Off 
                 Off 
                 Off 
                 Off 
               
               
                 3 
                 53% 
                 Low 
                 Off 
                 Off 
                 Low 
                 Low 
                 Low 
                 Low 
                 Low 
               
               
                 4 
                 71% 
                 High 
                 Off 
                 Off 
                 High 
                 High 
                 High 
                 High 
                 High 
               
               
                 5 
                 75% 
                 Low 
                 Low 
                 Low 
                 Low 
                 Low 
                 Low 
                 Low 
                 Low 
               
               
                 6 
                 100%  
                 High 
                 High 
                 High 
                 High 
                 High 
                 High 
                 High 
                 High 
               
               
                   
               
            
           
         
       
     
     Table 4 is an embodiment of a temperature map  144  with six heating unit  122  configurations at different ACF  120  speeds. Table 4 illustrates a temperature map  144  that uses the combination of the configuration of the heating unit  122  and the speed of the ACF  120  to adjust and control heat output and a room temperature. The temperature map  144  provides a mapping among the heat output of the heating unit  122  in terms of the percentage of the maximum heat input, the speed of the ACF  120  in CFM, and the temperature rise for six heating unit  122  configurations (e.g. heat stages 1-6). When the heating unit  122  is in a first configuration (e.g. heat stage 1), the heating unit  122  is configured to output about 20% of the maximum heat input. In the first configuration, the heating unit  122  uses the least amount of energy with respect to the other configurations. The speed of the ACF  120  may be varied while the heating unit  122  is in the first configuration to adjust the temperature rise. The furnace controller  102  may increase the speed of the ACF  120  to reduce the temperature rise and decrease the speed of the ACF  120  to increase the temperature rise while the heating unit  122  is in the first configuration. When the heating unit  122  is in a second configuration (e.g. heat stage 2), the heating unit  122  is configured to output about 36% of the maximum heat input. In the second configuration, the heating unit  122  uses more energy than when the heating unit  122  is in the first configuration. For example, the heating unit  122  may increase the number of active burners  118  or transition the operating mode of the gas valves operably coupled to the active burners  118  to a high-flow rate. The furnace controller  102  may adjust the speed of the ACF  120  when the heating unit  122  is in the second configuration to further adjust the temperature rise. The temperature range and temperatures that are achievable when the heating unit  122  is in the second configuration are greater than when the heating unit  122  is in the first configuration. When the heating unit  122  is in a third configuration (e.g. heat stage 3), the heating unit  122  is configured to output about 51% of the maximum heat input. In the third configuration, the heating unit  122  uses more energy than when the heating unit  122  is in the second configuration. The furnace controller  102  may adjust the speed of the ACF  120  when the heating unit  122  is in the third configuration to further adjust the temperature rise. When the heating unit  122  is in a fourth configuration (e.g. heat stage 4), the heating unit  122  is configured to output about 64% of the maximum heat input. In the fourth configuration, the heating unit  122  uses more energy than when the heating unit  122  is in the third configuration. The furnace controller  102  may adjust the speed of the ACF  120  when the heating unit  122  is in the fourth configuration to further adjust the temperature rise. When the heating unit  122  is in a fifth configuration (e.g. heat stage 5), the heating unit  122  is configured to output about 80% of the maximum heat input. 
     In the fifth configuration, the heating unit  122  uses more energy than when the heating unit  122  is in the fourth configuration. The furnace controller  102  may adjust the speed of the ACF  120  when the heating unit  122  is in the fifth configuration to further adjust the temperature rise. When the heating unit  122  is in a sixth configuration (e.g. heat stage 6), the heating unit  122  is configured to output about 100% of the maximum heat input. In the sixth configuration, the heating unit  122  uses the most energy to achieve the highest temperature rise temperatures. The furnace controller  102  may adjust the speed of the ACF  120  when the heating unit  122  is in the sixth configuration to further adjust the temperature rise. 
     Table 4 illustrates that for each heating unit  122  configuration, the speed of the ACF  120  can be varied to adjust the temperature rise. As the speed of the ACF  120  increases, the temperature rise decreases. As the speed of the ACF  120  decreases, the temperature rise increases. Using a temperature map  144  like Table 4, the furnace controller  102  may reconfigure the heating unit  122  and/or adjust the speed of the ACF  120  to control the temperature rise. 
     
       
         
           
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 An embodiment of a temperature map 144 with six heating unit 122 
               
               
                 configurations at different ACF 120 speeds 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 Stage 1 
                 Stage 2 
                 Stage 3 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                 Temp  
                   
                   
                 Temp  
                   
                   
                 Temp  
               
               
                 % Input 
                 CFM 
                 Rise 
                 % Input 
                 CFM 
                 Rise 
                 % Input 
                 CFM 
                 Rise 
               
               
                   
               
               
                 20% 
                 250 
                 89 
                 36% 
                 250 
                 160 
                  51% 
                 260 
                 227 
               
               
                 20% 
                 500 
                 44 
                 36% 
                 500 
                 80 
                  51% 
                 500 
                 113 
               
               
                 20% 
                 750 
                 30 
                 36% 
                 750 
                 53 
                  51% 
                 750 
                 76 
               
               
                 20% 
                 1000 
                 22 
                 36% 
                 1000 
                 40 
                  51% 
                 1000 
                 57 
               
               
                 20% 
                 1250 
                 18 
                 36% 
                 1250 
                 32 
                  51% 
                 1250 
                 45 
               
               
                 20% 
                 1500 
                 15 
                 36% 
                 1500 
                 27 
                  51% 
                 1500 
                 38 
               
               
                 20% 
                 1750 
                 13 
                 36% 
                 1750 
                 23 
                  51% 
                 1750 
                 32 
               
               
                 20% 
                 2000 
                 11 
                 36% 
                 2000 
                 20 
                  51% 
                 2000 
                 28 
               
               
                 20% 
                 2250 
                 10 
                 36% 
                 2250 
                 18 
                  51% 
                 2250 
                 25 
               
               
                 20% 
                 2500 
                 9 
                 36% 
                 2500 
                 16 
                  51% 
                 2500 
                 23 
               
               
                 20% 
                 2750 
                 8 
                 36% 
                 2750 
                 15 
                  51% 
                 2750 
                 21 
               
               
                 20% 
                 3000 
                 7 
                 36% 
                 3000 
                 13 
                  51% 
                 3000 
                 19 
               
               
                 20% 
                 3250 
                 7 
                 36% 
                 3250 
                 12 
                  51% 
                 3250 
                 17 
               
               
                 20% 
                 3500 
                 6 
                 36% 
                 3500 
                 11 
                  51% 
                 3500 
                 16 
               
               
                 20% 
                 3750 
                 6 
                 36% 
                 3750 
                 11 
                  51% 
                 3750 
                 15 
               
               
                 20% 
                 4000 
                 6 
                 36% 
                 4000 
                 10 
                  51% 
                 4000 
                 14 
               
               
                   
               
            
           
           
               
               
               
            
               
                 Stage 4 
                 Stage 5 
                 Stage 6 
               
            
           
           
               
               
               
               
               
               
               
               
               
            
               
                   
                   
                 Temp  
                   
                   
                 Temp  
                   
                   
                 Temp  
               
               
                 % Input 
                 CFM 
                 Rise 
                 % Input 
                 CFM 
                 Rise 
                 % Input 
                 CFM 
                 Rise 
               
               
                   
               
               
                 64% 
                 250 
                 284 
                 80% 
                 250 
                 356 
                 100% 
                 250 
                 444 
               
               
                 64% 
                 500 
                 142 
                 80% 
                 500 
                 178 
                 100% 
                 500 
                 222 
               
               
                 64% 
                 750 
                 95 
                 80% 
                 750 
                 119 
                 100% 
                 750 
                 148 
               
               
                 64% 
                 1000 
                 71 
                 80% 
                 1000 
                 89 
                 100% 
                 1000 
                 111 
               
               
                 64% 
                 1250 
                 57 
                 80% 
                 1250 
                 71 
                 100% 
                 1250 
                 89 
               
               
                 64% 
                 1500 
                 47 
                 80% 
                 1500 
                 59 
                 100% 
                 1500 
                 74 
               
               
                 64% 
                 1750 
                 41 
                 80% 
                 1750 
                 51 
                 100% 
                 1750 
                 63 
               
               
                 64% 
                 2000 
                 35 
                 80% 
                 2000 
                 44 
                 100% 
                 2000 
                 56 
               
               
                 64% 
                 2250 
                 32 
                 80% 
                 2250 
                 40 
                 100% 
                 2250 
                 49 
               
               
                 64% 
                 2500 
                 28 
                 80% 
                 2500 
                 36 
                 100% 
                 2500 
                 44 
               
               
                 64% 
                 2750 
                 26 
                 80% 
                 2750 
                 32 
                 100% 
                 2750 
                 40 
               
               
                 64% 
                 3000 
                 24 
                 80% 
                 3000 
                 30 
                 100% 
                 3000 
                 37 
               
               
                 64% 
                 3250 
                 22 
                 80% 
                 3250 
                 27 
                 100% 
                 3250 
                 34 
               
               
                 64% 
                 3500 
                 20 
                 80% 
                 3500 
                 25 
                 100% 
                 3500 
                 32 
               
               
                 64% 
                 3750 
                 19 
                 80% 
                 3750 
                 24 
                 100% 
                 3750 
                 30 
               
               
                 64% 
                 4000 
                 18 
                 80% 
                 4000 
                 22 
                 100% 
                 4000 
                 28 
               
               
                   
               
            
           
         
       
     
     Table 5 is one embodiment of a temperature map  144  that provides a mapping between the duty cycle for a pulsed burner  118  and the temperature of the supply air. Table 5 illustrates a temperature map  144  that uses the duty cycle of a pulsed burner  118  can be adjusted to control a room temperature when the heating unit  122  is configured with a constant burner  118  and a pulsed burner  118 . The duty cycle of the pulsed burner  118  is the percentage of the time period that the pulsed burner  118  is active. Table 5 illustrates that the duty cycle of the pulsed burner  118  can be varied to adjust the temperature rise or the temperature of the supply air. As the duty cycle of the pulsed burner  118  increases, the temperature of the supply air increases. The furnace controller  102  can increase the temperature of the supply air by configuring the pulsed burner  118  with a higher duty cycle to stay active for a longer period of time. As the duty cycle of the pulsed burner  118  decreases, the temperature of the supply air decreases. The furnace controller  102  can decrease the temperature of the supply air by configuring the pulsed burner  118  with a lower duty cycle to stay active for a shorter period of time. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 An embodiment of a temperature map 144 for 
               
               
                 a heating unit 122 with a pulsed burner 118 
               
            
           
           
               
               
               
            
               
                   
                 Duty Cycle 
                 Temperature 
               
               
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 10% 
                 23 
               
               
                   
                 20% 
                 25 
               
               
                   
                 30% 
                 28 
               
               
                   
                 40% 
                 32 
               
               
                   
                 50% 
                 38 
               
               
                   
                 60% 
                 45 
               
               
                   
                 70% 
                 57 
               
               
                   
                 80% 
                 76 
               
               
                   
                 90% 
                 113 
               
               
                   
                 100%  
                 227 
               
               
                   
                   
               
            
           
         
       
     
       FIGS. 4-6, 8, 10, 11, and 13-15  are embodiments of various operating modes for the heating system  100 . The heating system  100  may be configured to implement any combination of the following operating modes to control a room temperature or the heat output of the heating system  100 . Additional information for each operating mode will be disclosed herein. One of ordinary skill in the art would appreciate that alternative embodiments of the operating modes described in  FIGS. 4-6, 8, 10, 11, and 13-15  also exist for adjusting other temperature or heat output parameters (e.g. temperature rise or supply air temperature) without departing from the spirit or scope of the present disclosure. 
       FIG. 4  is a flowchart of one embodiment of a heating control method  400  for operating a heating system  100  in a discharge air heating control mode. In a discharge air heating control mode the discharge air temperature or temperature rise can be adjusted by varying the speed of the ACF  120 . Method  400  is implemented by furnace controller  102  to adjust a discharge air temperature or temperature rise. 
     At step  402 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active to achieve a first temperature. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. At step  404 , the furnace controller  102  receives a temperature set point, for example, from the thermostat  132 . The temperature set point indicates a desired room temperature or supply air temperature for a room  158  or conditioned space. At step  406 , the furnace controller  102  determines a second speed for the ACF  120  using the temperature set point and a temperature map  144  that maps temperatures to speeds of ACF  120 . For example, the furnace controller  102  may use a temperature map  144  similar to Table 1 or Table 4. The furnace controller  102  may use the temperature set point as a key to look up an entry in the temperature map  144  that corresponds with the temperature set point (e.g., the supply air temperature) to identify the second speed for the ACF  120  from the temperature map  144 . In one embodiment, the second speed may be less than the first speed to provide more heat. As the speed of the ACF  120  decreases, the amount of air provided by the ACF  120  is reduced which leads to a increase in the amount of heat that is provided by the heating system  100  and an increase in the output temperature of the heating system  100 . Alternatively, the second speed may be greater than the first speed to provide less heat. As the speed of the ACF  120  increases, the amount of air provided by the ACF  120  increases which leads to a decrease in the amount of heat that is provided by the heating system  100  and a decrease in the output temperature of the heating system  100 . At step  408 , the furnace controller  102  transitions the ACF  120  from the first speed to the second speed in response to determining the second speed. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. 
     In one embodiment, the temperature map  144  may also map temperatures to configurations for the heating unit  122 . In such an embodiment, the furnace controller  102  may determine a second configuration for the heating unit  122  using the temperature set point and the temperature map  144 . For example, the temperature map  144  may be similar to Table 4. The furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in response to determining the second configuration. For example, the furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in addition to adjusting the speed of the ACF  120  or as an alternative to adjusting the speed of the ACF  120 . The furnace controller  102  may transmit one or more electrical signal to transition the heating unit  122  from the first configuration to the second configuration. Transitioning the heating unit  122  from the first configuration to the second configuration to provide more heat may comprise switching from the first set of active burners to a second set of active burners that comprises more burners  118  than the first set of active burners. Switching from the first set of active burners to the second set of active burners increases the overall number of active burners  118 , which allows the heating unit  122  to generate and to output more heat. Alternatively, transitioning the heating unit  122  from the first configuration to the second configuration to provide more heat may comprise activating a second set of burners. For example, the heating unit  122  may operate using both the first set of active burners and the second set of active burners. Operating the heating unit  122  with both the first set of active burners and the second set of active burners also increases the overall number of active burners  118  and allows the heating unit  122  to generate and to output more heat. Additionally or alternatively, transitioning the heating unit  122  to the second configuration to provide more heat may comprise increasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a low-fire mode to a high-fire mode. Increasing the speed of the CAB  106  and the pressure of the gas valve that is operably coupled to the first set of active burners allows the actives burners  118  to use more energy to generate and output more heat. Transitioning the heating unit  122  from the first configuration to the second configuration to provide less heat may comprise switching from the first set of active burners to a second set of active burners that comprises fewer burners  118  than the first set of active burners. Switching from the first set of active burners to the second set of active burners reduces the overall number of active burners  118 , which causes the heating unit  122  to generate and to output less heat. Additionally or alternatively, transitioning the heating unit  122  from the first configuration to the second configuration to produce less heat may comprise decreasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a high-fire mode to a low-fire mode. Decreasing the speed of the CAB  106  and the pressure of the gas valve that is operably coupled to the first set of active burners causes the active burners  118  to use less energy to generate and output less heat. 
       FIG. 5  is a flowchart of one embodiment of a heating control method  500  for operating a heating system  100  in an anti-stratification mode. In an anti-stratification mode the temperature rise can be reduced to resolve or to avoid stratification within a room  158 . Method  500  is implemented by furnace controller  102  to reduce temperature rise within a room  158 . 
     At step  502 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active to achieve a first temperature rise. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  504 , the furnace controller  102  obtains a return air temperature using the return air sensor  138 . At step  506 , the furnace controller  102  obtains a room air temperature using the room air temperature sensor  136 . At step  508 , the furnace controller  102  determines a temperature difference between the return air temperature and the room air temperature. The temperature difference between the return air temperature and the room air temperature corresponds with the temperature rise for the room  158  which may be used to determine whether stratification is occurring or may occur. In another embodiment, the furnace controller  102  may obtain a supply air temperature using the DAS  128  and determine the temperature difference between the supply air temperature and the return air temperature or the temperature difference between the supply air temperature and the room air temperature. The temperature difference between the supply air temperature and the return air temperature also corresponds with the temperature rise for the room  158  and may be used to determine whether stratification is occurring or may occur. 
     At step  510 , the furnace controller  102  compares the temperature difference to a temperature rise threshold  146  to determine whether the temperature difference is greater than the temperature rise threshold  146 . The temperature rise threshold  146  is a temperature difference threshold that indicates when stratification may occur. For example, stratification may occur when the temperature difference is greater than the temperature rise threshold  146 . At step  512 , the furnace controller  102  determines that the conditions for stratification have been satisfied and that stratification is occurring or may occur and proceeds to step  514  when the temperature difference is greater than the temperature rise threshold  146 . Otherwise, the furnace controller  102  returns to step  502  when the temperature difference is less than the temperature rise threshold  146 . The furnace controller  102  determines that the conditions for stratification have not been satisfied. 
     At step  514 , the furnace controller  102  transitions the ACF  120  from the first speed to a second speed to achieve a second temperature rise that is less than the first temperature rise. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. The second speed is greater than the first speed, which reduces the heat output or the supply air temperature of the heating system  100 . Reducing the supply air temperature of the heating system  100  reduces the temperature difference between the return air temperature and the room air temperature or the temperature difference between the supply air temperature and the return air temperature, which helps reduce or eliminate stratification in the room  158 . The furnace controller  102  may determine the second speed using a temperature map  144  that maps temperatures or temperature rises to speed of the ACF  120 . For example, the furnace controller  102  may use a temperature map  144  similar to Table 1 or Table 4. 
     In one embodiment, the temperature map  144  may also map temperatures or temperature rises to configurations for the heating unit  122 . For example, the temperature map  144  may be similar to Table 4. In such an embodiment, the furnace controller  102  may determine a second configuration for the heating unit  122  when the temperature difference is greater than the temperature rise threshold  146 . The furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in response to determining the second configuration. For example, the furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in addition to adjusting the speed of the ACF  120  or as an alternative to adjusting the speed of the ACF  120 . The furnace controller  102  may transmit one or more electrical signal to transition the heating unit  122  from the first configuration to the second configuration. Transitioning the heating unit  122  from the first configuration to the second configuration to provide less heat and to achieve the second temperature rise may be similar to as described in  FIG. 4  and may comprise switching from the first set of active burners to a second set of active burners that comprises less burners  118  than the first set of active burners or decreasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a high-fire mode to a low-fire mode. Transitioning the heating unit  122  to the second configuration reduces the supply air temperature of the heating system  100 , which reduces the temperature difference between the return air temperature and the room air temperature or the temperature difference between the supply air temperature and the return air temperature, which helps reduce or eliminate stratification in the room  158 . 
       FIG. 6  is a flowchart of an embodiment of a heating control method  600  for operating a heating system  100  in an energy saving mode. In an energy saving mode, the heating system  100  delivers a reduced temperature increase and allows the ACF  120  to gradually heat up a room over a longer period of time. The heating system  100  is configured to transition to the ACF  120  to a lower speed when additional heat is required and then to transition the ACF  120  to a higher speed when the additional heat is no longer required. Method  600  is implemented by furnace controller  102  to operate the ACF  120  to gradually heat up an area over a longer period of time. 
     At step  602 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active to achieve a first temperature. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The heating system may be in a low-energy mode when the furnace controller  102  operates the ACF  120  at the first speed and the heating unit  122  in the first configuration. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  604 , the furnace controller  102  compares the first temperature rise to a first temperature rise threshold  146 . The furnace controller  102  may use the DAS  128 , the return air sensor  138 , and/or the room air temperature sensor  136  to measure and determine the first temperature rise. The furnace controller  102  may then compare the first temperature rise to the first temperature rise threshold  146  to determine whether the first temperature rise is less than the first temperature rise threshold  146 . The first temperature rise threshold  146  may correspond with a lower limit for desired temperature rise or temperature rise range for a room  158 . The furnace controller  102  compares the first temperature rise and the first temperature rise threshold  146  to determine whether the current temperature rise (i.e. the first temperature rise) meets or exceeds the lower limit (i.e. the first temperature rise threshold  146 ) for the desired temperature rise for the room  158 . At step  606 , the furnace controller  102  determines that the current temperature rise does not meet or exceed the lower limit for the desired temperature rise for the room  158  and proceeds to step  608  when the first temperature rise is less than the first temperature rise threshold  146 . Otherwise, the furnace controller  102  determines that the current temperature rise meets or exceeds the desired temperature rise for the room  158  and returns to step  604  when the first temperature rise is greater than the first temperature rise threshold  146 . 
     At step  608 , the furnace controller  102  transitions the ACF  120  from the first speed to a second speed to achieve a second temperature rise. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. The second temperature rise is greater than the first temperature rise. The second speed is less than the first speed, which increases the heat output and the supply air temperature of the heating system  100 . The increase in the supply air temperature leads to an increase in the temperature rise of the room  158 . The furnace controller  102  may determine the second speed using a temperature map  144 . For example, the furnace controller  102  may use a temperature map  144  similar to Table 1 or Table 4. At step  610 , the furnace controller  102  compares the second temperature rise to a second temperature rise threshold  146  to determine whether the second temperature rise is greater than the second temperature rise threshold  146 . The second temperature rise threshold  146  may correspond with an upper limit for the desired temperature rise or temperature rise range for the room  158 . The furnace controller  102  compares the second temperature rise and the second temperature rise threshold  146  to determine whether the new current temperature rise (i.e. the second temperature rise) meets or exceeds the upper limit (i.e. the second temperature rise threshold  146 ) for the desired temperature rise for the room  158 . At step  612 , the furnace controller  102  determines that the new current temperature rise meets or exceeds the upper limit for the desired temperature rise for the room  158  and proceeds to step  614  when the second temperature rise is greater than the second temperature rise threshold  146 . Otherwise, the furnace controller  102  determines that the new current temperature rise does not meet or exceed the upper limit for the desired temperature rise of the room  158  and returns to step  610  when the second temperature rise is less than the second temperature rise threshold  146 . 
     At step  614 , the furnace controller  102  transitions the ACF  120  from the second speed to a third speed to achieve a third temperature rise that is less than the second temperature rise. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the second speed to the third speed. The third speed is greater than second speed, which reduces the heat output and the supply air temperature of the heating system  100 . The reduction in the supply air temperature leads to a decrease in the temperature rise of the room  158 . The third speed may be the same as or different than the first speed. For example, the third speed may be equal to the first speed to return the heating system  100  to a low-energy mode. The furnace controller  102  may determine the third speed using a temperature map  144 . For example, the furnace controller  102  may use a temperature map  144  similar to Table 1 or Table 4. 
     In one embodiment, the furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in response to adjust the temperature rise. For example, the furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in addition to adjusting the speed of the ACF  120  or as an alternative to adjusting the speed of the ACF  120 . The furnace controller  102  may use a temperature map  144  to determine the second configuration based on the desired temperature rise. For example, the temperature map  144  may be similar to Table 4. The furnace controller  102  may transmit one or more electrical signal to transition the heating unit  122  from the first configuration to the second configuration. Transitioning the heating unit  122  from the first configuration to the second to provide more heat and to increase the temperature rise may be similar to as described in  FIG. 4  and may comprise switching from the first set of active burners to a second set of active burners that comprises more burners  118  than the first set of active burners, activating a second set of burners, or increasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a low-fire mode to a high-fire mode. Transitioning the heating unit  122  from the first configuration to the second configuration to provide less heat and to reduce the temperature rise may be similar to as described in  FIG. 4  and may comprise switching from the first set of active burners to a second set of active burners that comprises less burners  118  than the first set of active burners or decreasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a high-fire mode to a low-fire mode. 
       FIG. 7  is a graph  700  of one embodiment of operating a heating system  100  in an energy saving mode, such as by using method  600  in  FIG. 6 . Axis  704  indicates time, for example, in seconds or minutes, and axis  702  indicates a temperature rise, for example, in degrees Celsius or Fahrenheit. Line  750  represents the temperature rise over time. At a time t 0    706 , the heating system  100  is operating in a low-energy mode and produces a first temperature rise. The furnace controller  102  compares the current temperature rise (i.e. the first temperature rise) to a first temperature rise threshold  712  (e.g. temperature rise threshold  146 ) to determine whether the current temperature rise meets or exceeds a lower limit (i.e. the first temperature rise threshold  712 ) for a desired temperature rise range. At time t 1    708 , the furnace controller  102  determines that the first temperature rise is less than the first temperature rise threshold  712 . The furnace controller  102  may adjust the speed of the ACF  120  and/or the configuration of the heating unit  122  to achieve a second temperature rise that is greater than the first temperature rise. At time t 2    710 , the furnace controller  102  compares the new current temperature rise (i.e. the second temperature rise) to a second temperature rise threshold  714  (e.g. temperature rise threshold  146 ) to determine whether the new current temperature rise meets or exceeds an upper limit (i.e. the second temperature rise threshold  714 ) for the desired temperature rise range. The furnace controller  102  determines that the second temperature rise is greater than or equal to the second temperature rise threshold  714 . The furnace controller  102  may adjust the speed of the ACF  120  and/or the configuration of the heating unit  122  to achieve a third temperature rise that is less than the second temperature rise. 
       FIG. 8  is a flowchart of an embodiment of a heating control method  800  for operating a heating system  100  in a rapid response heat control mode. In the rapid response mode, the heating system  100  quickly heats up a room  158  without overshooting a temperature set point. Method  800  is implemented by furnace controller  102  to monitor and adjust discharge air temperature as the heating system rapidly provides heat to reach a target temperature set point without overheating and exceeding the temperature set point. 
     At step  802 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active to achieve a first temperature. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. Operating the ACF  120  at the first speed and the heating unit  122  in the first configuration provides heat to the space or room  158 . The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  804 , the furnace controller  102  determines a first temperature difference between the first temperature and a temperature set point. The furnace controller  102  may obtain the temperature set point from the thermostat  132 . The first temperature difference indicates how close the current temperature (i.e. the first temperature) is to the temperature set point. At step  806 , the furnace controller  102  compares the first temperature difference to a first temperature difference threshold  152  to determine whether the first temperature difference is less than the first temperature difference threshold  152 . The first temperature difference threshold  152  is a predetermined threshold that is used to determine whether the current temperature is within a first predetermined range of the temperature set point. The furnace controller  102  compares the first temperature difference to the first temperature difference threshold  152  to determine whether the current temperature is within the first predetermined range of the temperature set point. At step  808 , the furnace controller  102  determines that the current temperature is within the first predetermined range of the temperature set point and proceeds to step  810  when the first temperature difference is less than the first temperature difference threshold  152 . Otherwise, the furnace controller  102  determines that the current temperature is not within the first predetermined range of the temperature set point and returns to step  802  when the first temperature difference is greater than the first temperature difference threshold  152 . 
     At step  810 , the furnace controller  102  transitions the ACF  120  from the first speed to a second speed to achieve a second temperature that is less than the first temperature. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. As the temperature of the room  158  approaches the temperature set point the furnace controller  102  will reduce the amount of heat that is supplied to the room  158  by operating with a lower heat output. The second speed is greater than the first speed, which reduces the heat output and the supply air temperature of the heating system  100 . Operating the ACF  120  in the second speed provides less heat to the room than operating the ACF  120  at the first speed. The furnace controller  102  may determine the second speed using a temperature map  144 . For example, the temperature map  144  may be similar to Table 1 or Table 4. At step  812 , the furnace controller  102  determines a second temperature difference between the second temperature and the temperature set point. 
     At step  814 , the furnace controller  102  compares the second temperature difference to a second temperature difference threshold  152  to determine whether the second temperature difference is less than the second temperature difference threshold  152 . The second temperature difference threshold  152  is another predefined threshold that is used to determine whether the current temperature is within a second predetermined range of the temperature set point. The furnace controller  102  compares the second temperature difference to the second temperature difference threshold  152  to determine whether the current temperature is within the second predefined range of the temperature set point. At step  816 , the furnace controller  102  determines that the current temperature is within the second predetermined range of the temperature set point and proceeds to step  818  when the second temperature difference is less than the second temperature difference threshold  152 . Otherwise, the furnace controller  102  determines that current temperature is not within the second predetermined range of the temperature set point and returns to step  812  when the second temperature difference is greater than the second temperature difference threshold  152 . 
     At step  818 , the furnace controller  102  transitions the ACF  120  from the second speed to a third speed to achieve a third temperature that is less than the second temperature. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the second speed to the third speed. As the temperature of the room  158  approaches the temperature set point the furnace controller  102  will further reduce the amount of heat that is supplied to the room  158  by operating with an even lower heat output. The third speed is greater than the second speed, which further reduces the heat output and the supply air temperature of the heating system  100 . Operating the ACF  120  in the third speed provides less heat to the room than operating the ACF  120  at the second speed. The furnace controller  102  may determine the third speed using a temperature map  144 . For example, the temperature map  144  may be similar to Table 1 or Table 4. In an embodiment, the furnace controller  102  may determine a temperature difference, compare the temperature difference to a temperature difference threshold  152 , and adjust the speed of the ACF  120  as many times as necessary to gradually reduce the heat output and supply air temperature of the heating system  100  as the room temperature approaches the temperature set point without overshooting the temperature set point. 
     In one embodiment, the furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in response to adjust the temperature. For example, the furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration in addition to adjusting the speed of the ACF  120  or as an alternative to adjusting the speed of the ACF  120 . The furnace controller  102  may transmit one or more electrical signal to transition the heating unit  122  from the first configuration to the second configuration. Transitioning the heating unit  122  from the first configuration to the second configuration to provide more heat and to increase the temperature may be similar to as described in  FIG. 4  and may comprise switching from the first set of active burners to a second set of active burners that comprises more burners  118  than the first set of active burners, activating a second set of burners, or increasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a low-fire mode to a high-fire mode. Transitioning the heating unit  122  from the first configuration to the second configuration to provide less heat and to reduce the temperature may be similar to as described in  FIG. 4  and may comprise switching from the first set of active burners to a second set of active burners that comprises less burners  118  than the first set of active burners or decreasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a high-fire mode to a low-fire mode. 
       FIG. 9  is a graph  900  of one embodiment of operating a heating system  100  in a rapid response heat control mode, such as by using method  800  in  FIG. 8 . Axis  904  indicates time, for example, in seconds or minutes, and axis  902  indicates a temperature, for example, in degrees Celsius or Fahrenheit. Line  950  represents the temperature over time. At a time t 0    906 , the heating system  100  produces a first temperature. At time t 1    908 , the furnace controller  102  determines a first temperature difference  918  between the current temperature and a temperature set point  912 . The furnace controller  102  then compares the first temperature difference  918  to a first temperature difference threshold  914  (e.g. the temperature difference threshold  152 ) to determine whether the current temperature is within a first predetermined range of the temperature set point  912 . The furnace controller  102  determines that current temperature is within the first predetermined range of the temperature set point  912  when the first temperature difference  918  is less than or equal to the first temperature difference threshold  914 . The furnace controller  102  may adjust the speed of the ACF  120  and/or the configuration of the heating unit  122  to achieve a second temperature that provides less heat than the first temperature to reduce the heat output and the supply air temperature of the heating system  100 . The furnace controller  102  may use a temperature map  144  to adjust the speed of the ACF  120  and/or the configuration of the heating unit  122 . At time t 2    910 , the furnace controller  102  determines a second temperature difference  920  between the new current temperature and the temperature set point. The furnace controller  102  then compares the second temperature difference  920  to a second temperature difference threshold  916  (e.g. temperature difference threshold  152 ) to determine whether the new current temperature is within a second predetermined range of the temperature set point  912 . The furnace controller  102  determines that the new current temperature is within the second predetermined range of the temperature set point  912  when the second temperature rise is less than or equal to the second temperature difference threshold  916 . The furnace controller  102  may adjust the speed of the ACF  120  and/or the configuration of the heating unit  122  to achieve a third temperature that provides less heat than the second temperature and further reduces the heat output and the supply air of the heating system  100 . 
       FIG. 10  is a flowchart of an embodiment of a heating control method  1000  for operating a heating system  100  in a self-calibration mode. In the self-calibration mode, the heating system  100  updates temperature maps  144  for the heating system  100  based on environmental conditions. Method  1000  is implemented by furnace controller  102  to test and modify factory default settings or mappings in a temperature map  144  using information that is acquired from a job site. Method  1000  modifies temperatures in the temperature map  144  when the measured temperature for a given ACF  120  speed is different than an expected temperature set point. 
     At step  1002 , the furnace controller  102  determines a first speed for the ACF  120  that corresponds with a temperature set point (e.g. a desired room temperature or supply air temperature) using a temperature map  144  that maps temperature to speeds of the ACF  120 . For example, the furnace controller  102  may use a temperature map  144  similar to Table 1 or Table 4. The furnace controller  102  may use the temperature set point as a key to look up an entry in the temperature map  144  that corresponds with temperature set point to identify the second speed for the ACF  120  from the temperature map  144 . At step  1004 , the furnace controller  102  operates the ACF  120  at the first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  1006 , the furnace controller  102  measures a first temperature while operating the ACF  120  at the first speed. The furnace controller  102  may measure the first temperature using the DAS  128 , the return air sensor  138 , or the room air temperature sensor  136 . At step  1008 , the furnace controller  102  determines a temperature difference between the first temperature and the temperature set point. The first temperature difference indicates how far the first temperature that is achieved by the heating system  100  is from the expected temperature set point. At step  1010 , the furnace controller  102  compares the temperature difference to a temperature difference threshold  152  to determine whether the temperature difference is greater than the temperature difference threshold  152 . The temperature difference threshold  152  may represent a tolerance limit or a temperature range that the temperature set point may vary within. At step  1012 , the furnace controller  102  determines that the first temperature is not within the tolerance limits of the temperature set point and proceeds to step  1014  when the temperature difference is greater than the temperature difference threshold  152 . When the temperature difference is greater than the temperature difference threshold  152  the default settings or mapping may not be accurate based on environmental conditions for the heating system  100 . Otherwise, the furnace controller  102  determines that the first temperature is within the tolerance limits of the temperature set point and terminates method  1000  when the temperature difference is less than the temperature difference threshold  152 . At step  1014 , the furnace controller  102  modifies the temperature map  144  to map the first speed to the first temperature. The furnace controller  102  modifies the entry in the temperature map  144  with the temperature that is measured (i.e. the first temperature) when the ACF  120  is operating at the first speed. Updating the temperature map  144  provides a more accurate mapping between the speed of the ACF  120  and the output temperature or temperature rise when operating at the first speed based on environmental conditions for the heating system  100 . 
       FIG. 11  is a flowchart of another embodiment of a heating control method  1100  for operating a heating system  100  in a self-calibration mode. Method  1100  is implemented by furnace controller  102  in the heating system  100  to update temperature maps  144  for the heating system  100  based on environmental conditions. In particular, method  1100  is implemented to modify a speed for the ACF  120  in a temperature map  144  that corresponds with a temperature set point. 
     At step  1102 , the furnace controller  102  determines a first speed for the ACF  120  that corresponds with a temperature set point (e.g. a desired room temperature or supply air temperature) using a temperature map  144  that maps temperatures to speeds of the ACF  120 . For example, the furnace controller  102  may use a temperature map  144  similar to Table 1 or Table 4. The the furnace controller  102  may use the temperature set point as a key to look up an entry that corresponds with the temperature set point to identify the first speed for the ACF  120  from the temperature map  144 . At step  1104 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  1106 , the furnace controller  102  measures a first temperature while operating the ACF  120  at the first speed. The furnace controller  102  may measure the first temperature using the DAS  128 , the return air sensor  138 , or the room air temperature sensor  136 . At step  1108 , the furnace controller  102  determines a temperature difference between the first temperature and the temperature set point. The first temperature difference indicates how far the first temperature that is achieved by the heating system  100  is from the expected temperature set point. At step  1110 , the furnace controller  102  compares the temperature difference to a temperature difference threshold  152  to determine whether the temperature difference is greater than the temperature difference threshold  152 . The temperature difference threshold  152  may represent a tolerance limit or a temperature range that the temperature set point may vary within. The furnace controller  102  compares the first temperature difference to the temperature difference threshold  152  to determine whether the first temperature is within the tolerance limits of the temperature set point. At step  1112 , the furnace controller  102  determines that the first temperature is not within the tolerance limits of the temperature set point and proceeds to step  1114  when the temperature difference is greater than the temperature difference threshold  152 . When the temperature difference is greater than the temperature difference threshold  152  the default settings or mapping may not be accurate based on environmental conditions for the heating system  100 . For example, extreme environmental conditions may cause the heating system  100  to underperform when using default settings or mappings. Otherwise, the furnace controller  102  determines that the first temperature is within the tolerance limits of the temperature set point and terminates method  1100  when the temperature difference is less than the temperature difference threshold  152 . 
     At step  1114 , the furnace controller  102  transitions the ACF  120  from the first speed to a second speed. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. The furnace controller  102  selects the second speed to adjust the first temperature to a second temperature that is closer to the temperature set point. For example, the furnace controller  102  uses the temperature map  144  to determine the second speed. The second speed may be greater than the first speed to reduce the first temperature to a lower temperature. Alternatively, the second speed may be less than the first speed to increase the first temperature to a higher temperature. At step  1116 , the furnace controller  102  measures a second temperature while operating the ACF  120  at the second speed. At step  1118 , the furnace controller  102  determines a second temperature difference between the second temperature and the temperature set point. The second temperature difference indicates how far the second temperature is from the temperature set point. 
     At step  1120 , the furnace controller  102  compares the second temperature difference to the temperature difference threshold  152  to determine whether the second temperature difference is less than the temperature difference. The furnace controller  102  compares the second temperature difference to the temperature difference threshold  152  to determine whether the second temperature is within the tolerance limits of the temperature set point. At step  1122 , the furnace controller  102  determines that the second temperature is within the tolerance limits of the temperature set point and proceeds to step  1124  when the second temperature difference is less than the temperature difference threshold  152 . Otherwise, the furnace controller  102  determines that the second temperature is not within the tolerance limits of the temperature set point and returns to step  1114  to select a different second speed when the second temperature difference is greater than the temperature difference threshold  152 . At step  1124 , the furnace controller  102  updates the temperature map  144  to map the second speed to the temperature set point. The furnace controller  102  modifies the entry in the temperature map  144  with the second speed that is used to obtain the second temperature that is within the tolerance limits of the temperature set point. 
       FIG. 12  is a graph  1200  of one embodiment of operating a heating system  100  in a self-calibration mode, such as by using method  1000  in  FIG. 10  and method  1100  in  FIG. 11 . Axis  1204  indicates time, for example, in seconds or minutes, and axis  1202  indicates a temperature, for example, in degrees Celsius or Fahrenheit. Line  1250  represents the temperature over time. At a time t 0    1206 , the furnace controller  102  determines a first speed for the ACF  120  that corresponds with a temperature set point  1218  using a temperature map  144  that maps temperatures to speeds of the ACF  120 . For example, the temperature map  144  may be similar to Table 1 or Table 4. At time t 1    1208 , the furnace controller  102  measures a first temperature and determines a first temperature difference  1220  between the first temperature and a temperature set point  1218 . The furnace controller  102  compares the first temperature difference  1220  to a temperature difference threshold  1214  (e.g. temperature difference threshold  152 ) to determine whether the first temperature is within the tolerance limits of the temperature set point. The furnace controller  102  determines that the first temperature is not within the tolerance limits of the temperature set point when the first temperature difference  1220  is greater than the temperature difference threshold  1214 . In one embodiment, the furnace controller  102  updates the temperature map  144  to map the first temperature to the first speed of the ACF  120 . The furnace controller  102  modifies an entry in the temperature map  144  with the temperature that is measured (i.e. the first temperature) when the ACF  120  is operating at the first speed. 
     In another embodiment, the furnace controller  102  may adjust the speed of the ACF  120  and/or the configuration of the heating unit  122  to achieve a second temperature that is closer to the temperature set point  1218  in response to determining that the first temperature difference  1220  is greater than the temperature difference threshold  1214 . For example, the furnace controller  102  may transition the ACF  120  from a first speed to a second speed. The second speed may be greater than the first speed to reduce the first temperature to a lower temperature. Alternatively, the second speed may be less than the first speed to increase the first temperature to a higher temperature. At time t 2    1210 , the furnace controller  102  determines a second temperature difference  1222 . The furnace controller  102  compares the second temperature difference  122  to the temperature difference threshold  1214  to determine whether the second temperature is within the tolerance limits of the temperature set point. The furnace controller  102  determines that the second temperature is within the tolerance limits of the temperature set point when the second temperature is less than or equal to the temperature difference threshold  1214 . The furnace controller  102  updates the temperature map  144  to map the second speed and/or the configuration of the heating unit  122  to the temperature set point. The furnace controller  102  modifies the entry in the temperature map  144  with the second speed or configuration of the heating unit  122  that is used to obtain the second temperature that is within the tolerance limits of the temperature set point. 
       FIG. 13  is a flowchart of an embodiment of a heating control method  1300  for operating a heating system in an auto heating commissioning mode. Method  1300  is implemented by the furnace controller  102  in the heating system  100  to adjust the speed of the ACF  120  to adjust the temperature that is used for burning lubricants during maintenance to control the smoke output of the heating system  100 . 
     At step  1302 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner  118  from a plurality of burners  118  and with less than all of the burners  118  active to burn a lubricant at a first temperature. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  1304 , the furnace controller  102  measures a smoke output measurement for the first temperature, for example, using the smoke sensor  162 . At step  1306 , the furnace controller  102  compares the smoke output measurement to a smoke output measurement threshold  150 . The smoke output threshold  150  may be a predetermined threshold that indicates the maximum amount of smoke output that is allowed. For example, the smoke output of the heating system  100  may be limited by the smoke output threshold  150  for safety reasons. The furnace controller  102  compares the smoke output measurement to the smoke output threshold  150  to determine whether the smoke output measurement is greater than the smoke output threshold  150 . In other words, the furnace controller  102  determines whether too much smoke is being generated at the current operating temperature. At step  1308 , the furnace controller  102  determines that too much smoke is being generated and proceeds to step  1310  when the smoke output measurement is greater than the smoke output threshold  150 . Otherwise, the furnace controller  102  determines that too much smoke is not being generated and proceeds to step  1312  when the smoke output measurement is less than the smoke output threshold  150 . 
     At step  1310 , the furnace controller  102  transitions the ACF  120  from the first speed to a second speed to burn the lubricant at a second temperature that is less than the first temperature. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. The second speed is greater than the first speed, which reduces the heat output of the heating system  100  and allows the lubricant to be burned at a lower temperature. Reducing the temperature from the first temperature to the second temperature reduces the amount of smoke that is generated and the smoke output measurement. The furnace controller  102  may determine the second speed using a temperature map  144 . For example, the temperature map  144  may be similar to Table 1 or Table 4. 
     Returning to step  1308 , the furnace controller  102  proceeds to step  1312  when the smoke output measurement is less than the smoke output threshold  150 . At step  1312 , the furnace controller  102  transitions the ACF  120  from the first speed to a second speed to burn the lubricant at a second temperature that is greater than the first temperature. The furnace controller  102  may transmit one or more electrical signal to transition the ACF  120  from the first speed to the second speed. The second speed is less than the first speed, which increases the heat output of the heating system  100  and allows the lubricant to be burned at a higher temperature. The furnace controller  102  may burn the lubricant at a higher temperature to increase efficiency or reduce the time required to burn the lubricant. 
       FIG. 14  is a flowchart of another embodiment of a heating control method  1400  for operating a heating system  100  in an auto heating commissioning mode. Method  1400  is implemented by the furnace controller  102  in the heating system  100  to adjust the configuration of the heating unit  122  to adjust the temperature that is used for burning lubricants during maintenance to control the smoke output of the heating system  100 . 
     At step  1402 , the furnace controller  102  operates the ACF  120  at a first speed and the heating unit  122  in a first configuration with at least one active burner from a plurality of burners and with less than all of the burners active to burn a lubricant at a first temperature. For example, the heating unit  122  may be configured such that a first set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  is active and a second set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  is inactive. The active burners  118  may operate in either the low-fire mode or the high-fire mode. The furnace controller  102  may transmit one or more electrical signal to operate the ACF  120  in the first speed and the heating unit  122  in the first configuration. 
     At step  1404 , the furnace controller  102  measure a smoke output measurement for the first temperature, for example, using smoke sensor  162 . At step  1406 , the furnace controller  102  compares the smoke output measurement to a smoke output threshold  150 . The smoke output threshold  150  is similar to as described in  FIG. 13 . The furnace controller  102  compares the smoke output measurement to the smoke output threshold  150  to determine whether the smoke output measurement is greater than the smoke output threshold  150 . The furnace controller  102  determines whether too much smoke is being generated at the current operating temperature. At step  1408 , the furnace controller  102  determines that too much smoke is being generated and proceeds to step  1410  when the smoke output measurement is greater than the smoke output threshold  150 . Otherwise, the furnace controller  102  determines that too smoke is not being generated and proceeds to step  1412  when the smoke output measurement is less than the smoke output threshold  150 . 
     At step  1410 , the furnace controller  102  transitions the heating unit  122  from the first configuration to a second configuration to burn the lubricant at a second temperature that is less than the first temperature. The furnace controller  102  may transmit one or more electrical signal to transition the heating unit  122  from the first configuration to the second configuration. The furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration to provide less heat and to reduce the temperature similar to as described in  FIG. 4 . Transitioning the heating unit  122  to the second configuration to provide less heat may comprise switching from the first set of active burners to a second set of active burners that comprises less burners  118  than the first set of active burners or decreasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a high-fire mode to a low-fire mode. The furnace controller  102  may determine the second configuration using a temperature map  144 . For example, the temperature map  144  may be similar to Table 2, Table 3, or Table 4. 
     Returning to step  1408 , the furnace controller  102  proceeds to step  1412  when the smoke output measurement is less than the smoke output threshold  150 . At step  1412 , the furnace controller  102  transitions the heating unit  122  from the first configuration to a second configuration to burn the lubricant at a second temperature that is greater than the first temperature. The furnace controller  102  may transmit one or more electrical signal to transition the heating unit  122  from the first configuration to the second configuration. The furnace controller  102  may transition the heating unit  122  from the first configuration to the second configuration to provide more heat and to increase the temperature similar to as described in  FIG. 4 . Transitioning the heating unit  122  to the second configuration to provide more heat may comprise switching from the first set of active burners to a second set of active burners that comprises more burners  118  than the first set of active burners, activating a second set of burners, or increasing the speed of the CAB  106  and the pressure to a gas valve operably coupled to the first set of active burners to transition the first set of active burners from a low-fire mode to a high-fire mode. 
       FIG. 15  is a flowchart of an embodiment of a heating control method  1500  for operating a heating system  100  in a gas pulse modulation temperature control mode. Method  1500  is implemented by the furnace controller  102  in the heating system  100  to adjust a discharge air temperature or temperature rise using pulse width modulation with a pulsed burner  118 . The heating unit  122  may be configured with a constant burner  118  and a pulsed burner  118  similarly to as described in  FIG. 3 . 
     At step  1502 , the furnace controller  102  activates a constant burner  118  from a plurality of burners  118  within the heating unit  122 . For example, the heating unit  122  may be configured such that a first burner  118  or set of burners (e.g. the first set of burners  114 ) in a first segment of the gas manifold  160  are configured as constant burners and a second burner  118  or set of burners (e.g. the second set of burners  116 ) in a second segment of the gas manifold  160  are configured as pulsed burners  118 . The constant burner  118  is configured to remain active during operation. The pulsed burners  118  are configured to toggle between an active mode and an inactive mode. The furnace controller  102  may transmit one or more electrical signal to activate the constant burner  118 . 
     At step  1504 , the furnace controller  102  receives a temperature set point (e.g. a desired room temperature or supply air temperature), for example, from the thermostat  132 . At step  1506 , the furnace controller  102  determines a percentage of a time period that a pulsed burner  118  from the plurality of burners  118  is active using the temperature set point and a temperature map  144  that maps temperatures to percentages of the time period that the pulsed burner  118  is active. For example, the temperature map  144  may be similar to Table 5. The furnace controller  102  may use the temperature set point as a key to look up an entry in the temperature map  144  to identify the percentage of the time period that the pulsed burner  118  is active (e.g. a duty cycle) that corresponds with the temperature set point from the temperature map  144 . At step  1508 , the furnace controller  102  toggles the pulsed burner  118  between the active mode and the inactive mode based on the determination of the percentage of the time period that the pulsed burner  118  is active. The furnace controller  102  may transmit one or more electrical signal to toggle the pulsed burner  118 . The percentage of the time period that the pulsed burner  188  is active controls how long the pulsed burner  118  stays in the active mode before toggling to the inactive mode. 
     When the furnace controller  102  receives another temperature set point, the furnace controller  102  may repeat step  1506  and  1508  to determine another percentage of the time period that the pulsed burner  118  is active and to toggle the pulsed burner  118  based on the percentage of the time period that the pulsed burner  118  is active. For example, the furnace controller  102  may receive a new temperature set point that is a higher temperature than the original temperature set point. The furnace controller  102  may use the temperature map  144  to identify a higher percentage of the time period that the pulsed burner  118  is active (i.e. a higher duty cycle) to provide more heat to achieve the new temperature set point. Alternatively, the furnace controller  102  may receive a new temperature set point that is a lower temperature than the original temperature set point. The furnace controller  102  may use the temperature map  144  to identify a lower percentage of the time period that the pulsed burner  118  is active (i.e. a lower duty cycle) to provide less heat to achieve the new temperature set point. 
     While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented. 
     In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein. 
     To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants note that they do not intend any of the appended claims to invoke 35 U.S.C. § 112(f) as it exists on the date of filing hereof unless the words “means for” or “step for” are explicitly used in the particular claim.