Patent Publication Number: US-2022235965-A1

Title: Retrofit damper assembly

Description:
This application is a continuation of U.S. patent application Ser. No. 16/006,782, which was filed on Jun. 12, 2018, and is entitled, “RETROFIT DAMPER ASSEMBLY,” the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure pertains to a Heating, Ventilation, and/or Air Conditioning (HVAC) system for a building. More particularly, the present disclosure pertains to devices for adding zoning to an existing HVAC system. 
     BACKGROUND 
     Heating, Ventilation, and/or Air Conditioning (HVAC) systems are often used to control the comfort level within a building or other structure. Such HVAC systems typically include an HVAC controller that controls various HVAC components of the HVAC system in order to affect and/or control one or more environmental conditions within the building. In many cases, the HVAC controller is mounted within the building and provides control signals to various HVAC components of the HVAC system. In some buildings, there may be a desire to add zoning to the HVAC system in order to better control one or more environmental conditions within the building. Zoning can provide the ability to control environmental conditions within a particular area or region of a building. Improvements in the hardware, user experience, and functionality of such HVAC systems, including the ability to retrofit zoning to an existing HVAC system, would be desirable. 
     SUMMARY 
     The disclosure relates generally to devices for retrofitting an existing HVAC system with zoning. In some cases, these devices may also be used for zoning in new constructions, but are particularly designed for use in adding zoning to an existing HVAC system. In some cases, the disclosure relates to a damper assembly that is configured for placement within a duct of a ductwork system that supplies conditioned air through a register boot to a register vent. The damper assembly includes a damper that is configured to be deployed within the duct and is configured to articulate from a deployment configuration, which facilitates advancement of the damper through the register boot and into the duct, to an operational configuration, in which the damper is positioned within the duct and able to selectively control how much conditioned air being supplied through the duct is permitted to pass by the damper and exit the register vent. The damper assembly includes an elongated deployment member that extends from the damper and is configured to facilitate advancement of the damper through the register boot and into the duct, and is further configured to retain the damper in the duct when at least a portion of the elongated deployment member is anchored downstream of the damper. 
     Another example of the disclosure is a damper assembly that is configured for placement within a duct of a ductwork system that supplies conditioned air through a register boot to a register vent. The damper assembly includes a damper frame and a damper blade that is secured relative to the damper frame and is pivotable between a closed end position in which air moving through the duct is restricted from flowing past the damper blade and through the register vent, and an open end position in which air moving through the duct is less restricted from flowing past the damper blade and through the register vent. A damper motor is operably coupled to the damper blade and is configured to pivot the damper blade between the closed end position and the open end position. A deployment strap extends from the damper frame and is configured to facilitate advancement of the damper frame through the register boot and into the duct from an installation position in or downstream of the register boot. 
     Another example of the disclosure is a damper assembly that is configured for placement within a duct of a ductwork system that supplies conditioned air through a register boot to a register vent. The damper assembly includes a rigid damper frame having a frame periphery that has a lower profile in one direction and a higher profile in another direction, wherein the lower profile in the one direction aids a user in advancing the rigid damper frame through the register boot and into the duct, the rigid damper frame defining an air flow aperture. A rigid damper blade is pivotable between a closed end position in which the rigid damper blade forms a seal with the rigid damper frame and closes the air flow aperture of the rigid damper frame, and an open end position in which the rigid damper blade pivots and allows air to flow through the air flow aperture of the rigid damper frame. A flexible member extends outward from the rigid damper frame for engaging and forming a seal with at least part of an inner wall of the duct. 
     The preceding summary is provided to facilitate an understanding of some of the features of the present disclosure and is not intended to be a full description. A full appreciation of the disclosure can be gained by taking the entire specification, claims, drawings, and abstract as a whole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure may be more completely understood in consideration of the following description of various illustrative embodiments of the disclosure in connection with the accompanying drawings, in which: 
         FIG. 1  is a schematic view of an illustrative HVAC system servicing a building; 
         FIG. 2  is a schematic view of an illustrative HVAC control system that may facilitate access and/or control of the HVAC system of  FIG. 1 ; 
         FIG. 3  is a schematic view of an illustrative zoned HVAC system that includes a number of wireless dampers; 
         FIG. 4  is a perspective view of an illustrative damper deployed within a building&#39;s ductwork; 
         FIG. 5  is a perspective view of an illustrative damper assembly shown in a deployment configuration; 
         FIG. 6  is a perspective view of an illustrative damper assembly shown in an operational configuration, with the damper blade in a closed position; 
         FIG. 7  is a perspective view of an illustrative damper assembly shown in an operational configuration, with the damper blade in an open position; 
         FIG. 8  is a side perspective view of a portion of an illustrative damper assembly; 
         FIG. 8A  is a side perspective view of an illustrative damper assembly; 
         FIG. 8B  is a side perspective view of a portion of the illustrative damper assembly of  FIG. 8A ; 
         FIG. 8C  is a side perspective of a portion of the illustrative damper assembly of  FIG. 8A ; 
         FIG. 9  is a perspective view of an illustrative damper assembly; 
         FIG. 10  is a perspective view of a portion of an illustrative damper assembly; 
         FIG. 11  is a perspective view of an illustrative control module; 
         FIG. 12  is an exploded perspective view of the control module of  FIG. 11 ; 
         FIG. 12A  is a partially exploded perspective view of an illustrative control module; 
         FIGS. 13 through 18  are schematic views of illustrative antenna configurations; 
         FIG. 19  is a schematic block diagram of an illustrative damper assembly; 
         FIG. 20  is a schematic block diagram of an illustrative retrofit damper system; 
         FIG. 21  is a schematic block diagram of an illustrative damper assembly; 
         FIG. 22  is a schematic block diagram of an illustrative control module; 
         FIG. 23  is a schematic block diagram of an illustrative damper assembly; 
         FIG. 24  is a schematic block diagram of an illustrative damper system; 
         FIG. 25  is a schematic block diagram of an illustrative room comfort assembly; 
         FIG. 26  is a perspective view of an illustrative power module; 
         FIG. 27  is a perspective view of the illustrative power module of  FIG. 26  with a hinged top removed; 
         FIG. 28  is a perspective view of the hinged top of the illustrative power module of  FIG. 26 ; 
         FIG. 29  is a side view of an illustrative damper assembly having a single damper blade, the damper assembly shown disposed within a clear duct; 
         FIG. 30  is a perspective view of the illustrative damper assembly of  FIG. 29 , shown without the flexible polymeric portion of the blade; 
         FIG. 31  is a side view of an illustrative damper assembly having two damper blades, the damper assembly shown disposed within a clear duct; 
         FIG. 32  is a perspective view of the illustrative damper assembly of  FIG. 31 , shown without the flexible polymeric portions of the blades; and 
         FIG. 33  is a perspective view of a portion of the illustrative damper assembly of  FIG. 32 . 
     
    
    
     While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
     DESCRIPTION 
     The following description should be read with reference to the drawings wherein like reference numerals indicate like elements. The drawings, which are not necessarily to scale, are not intended to limit the scope of the disclosure. In some of the figures, elements not believed necessary to an understanding of relationships among illustrated components may have been omitted for clarity. 
     All numbers are herein assumed to be modified by the term “about”, unless the content clearly dictates otherwise. The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include the plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is contemplated that the feature, structure, or characteristic may be applied to other embodiments whether or not explicitly described unless clearly stated to the contrary. 
     The present disclosure is directed generally at building automation systems. Building automation systems are systems that control one or more operations of a building. Building automation systems can include HVAC systems, security systems, fire suppression systems, energy management systems and other systems. While HVAC systems with HVAC controllers are used as an example below, it should be recognized that the concepts disclosed herein can be applied to building automation systems more generally. 
       FIG. 1  is a schematic view of a building  2  having an illustrative heating, ventilation, and air conditioning (HVAC) system  4 . The illustrative HVAC system  4  of  FIG. 1  includes one or more HVAC components  6 , a system of ductwork and air vents including a supply air duct  10  and a return air duct  14 , and one or more HVAC controllers  18 . The one or more HVAC components  6  may include, but are not limited to, a furnace, a heat pump, an electric heat pump, a geothermal heat pump, an electric heating unit, an air conditioning unit, a humidifier, a dehumidifier, an air exchanger, an air cleaner, a damper, a valve, and/or the like. 
     It is contemplated that the HVAC controller(s)  18  may be configured to control the comfort level in the building or structure by activating and deactivating the HVAC component(s)  6  in a controlled manner. The HVAC controller(s)  18  may be configured to control the HVAC component(s)  6  via a wired or wireless communication link  20 . In some cases, the HVAC controller(s)  18  may be a thermostat, such as, for example, a wall mountable thermostat, but this is not required in all embodiments. Such a thermostat may include (e.g. within the thermostat housing) or have access to one or more temperature sensor(s) for sensing ambient temperature at or near the thermostat. In some instances, the HVAC controller(s)  18  may be a zone controller, or may include multiple zone controllers each monitoring and/or controlling the comfort level within a particular zone in the building or other structure. In some cases, the HVAC controller(s)  18  may communicate with one or more remote sensors, such as a remote sensor  21 , that may be disposed within the building  23 . In some cases, a remote sensor  21  may measure various environmental conditions such as but not limited to temperature. 
     In the illustrative HVAC system  4  shown in  FIG. 1 , the HVAC component(s)  6  may provide heated air (and/or cooled air) via the ductwork throughout the building  2 . As illustrated, the HVAC component(s)  6  may be in fluid communication with every room and/or zone in the building  2  via the ductwork  10  and  14 , but this is not required. In operation, when a heat call signal is provided by the HVAC controller(s)  18 , an HVAC component  6  (e.g. forced warm air furnace) may be activated to supply heated air to one or more rooms and/or zones within the building  2  via supply air ducts  10 . The heated air may be forced through supply air duct  10  by a blower or fan  22 . In this example, the cooler air from each zone may be returned to the HVAC component  6  (e.g. forced warm air furnace) for heating via return air ducts  14 . Similarly, when a cool call signal is provided by the HVAC controller(s)  18 , an HVAC component  6  (e.g. air conditioning unit) may be activated to supply cooled air to one or more rooms and/or zones within the building or other structure via supply air ducts  10 . The cooled air may be forced through supply air duct  10  by the blower or fan  22 . In this example, the warmer air from each zone may be returned to the HVAC component  6  (e.g. air conditioning unit) for cooling via return air ducts  14 . In some cases, the HVAC system  4  may include an internet gateway or other device  23  that may allow one or more of the HVAC components, as described herein, to communicate over a wide area network (WAN) such as, for example, the Internet. 
     In some cases, the system of vents or ductwork  10  and/or  14  can include one or more dampers  24  to regulate the flow of air, but this is not required. For example, one or more dampers  24  may be coupled to one or more HVAC controller(s)  18 , and can be coordinated with the operation of one or more HVAC components  6 . The one or more HVAC controller(s)  18  may actuate dampers  24  to an open position, a closed position, and/or a partially open position to modulate the flow of air from the one or more HVAC components to an appropriate room and/or zone in the building or other structure. The dampers  24  may be particularly useful in zoned HVAC systems, and may be used to control which zone(s) receives conditioned air and/or receives how much conditioned air from the HVAC component(s)  6 . In some cases, the one or more HVAC controller(s)  18  may use information from the one or more remote sensors  21 , which may be disposed within one or more zones, to adjust the position of one or more of the dampers  24  in order to cause a measured value to approach a setpoint in a particular zone or zones. 
     In many instances, one or more air filters  30  may be used to remove dust and other pollutants from the air inside the building  2 . In the illustrative example shown in  FIG. 1 , the air filter(s)  30  is installed in the return air duct  14 , and may filter the air prior to the air entering the HVAC component  6 , but it is contemplated that any other suitable location for the air filter(s)  30  may be used. The presence of the air filter(s)  30  may not only improve the indoor air quality, but may also protect the HVAC components  6  from dust and other particulate matter that would otherwise be permitted to enter the HVAC component. 
     In some cases, and as shown in  FIG. 1 , the illustrative HVAC system  4  may include an equipment interface module (EIM)  34 . When provided, the equipment interface module  34  may, in addition to controlling the HVAC under the direction of the thermostat, be configured to measure or detect a change in a given parameter between the return air side and the discharge air side of the HVAC system  4 . For example, the equipment interface module  34  may measure a difference (or absolute value) in temperature, flow rate, pressure, or a combination of any one of these parameters between the return air side and the discharge air side of the HVAC system  4 . In some instances, absolute value is useful in protecting equipment against an excessively high temperature or an excessively low temperature, for example. In some cases, the equipment interface module  34  may be adapted to measure the difference or change in temperature (delta T) between a return air side and discharge air side of the HVAC system  4  for the heating and/or cooling mode. The delta T for the heating and cooling modes may be calculated by subtracting the return air temperature from the discharge air temperature (e.g. delta T=discharge air temperature−return air temperature). 
     In some cases, the equipment interface module  34  may include a first temperature sensor  38   a  located in the return (incoming) air duct  14 , and a second temperature sensor  38   b  located in the discharge (outgoing or supply) air duct  10 . Alternatively, or in addition, the equipment interface module  34  may include a differential pressure sensor including a first pressure tap  39   a  located in the return (incoming) air duct  14 , and a second pressure tap  39   b  located downstream of the air filter  30  to measure a change in a parameter related to the amount of flow restriction through the air filter  30 . In some cases, it can be useful to measure pressure across the fan in order to determine if too much pressure is being applied as well as to measure pressure across the cooling A-coil in order to determine if the cooling A-coil may be plugged or partially plugged. In some cases, the equipment interface module  34 , when provided, may include at least one flow sensor that is capable of providing a measure that is related to the amount of air flow restriction through the air filter  30 . In some cases, the equipment interface module  34  may include an air filter monitor. These are just some examples. 
     When provided, the equipment interface module  34  may be configured to communicate with the HVAC controller  18  via, for example, a wired or wireless communication link  42 . In other cases, the equipment interface module  34  may be incorporated or combined with the HVAC controller  18 . In some instances, the equipment interface module  34  may communicate, relay or otherwise transmit data regarding the selected parameter (e.g. temperature, pressure, flow rate, etc.) to the HVAC controller  18 . In some cases, the HVAC controller  18  may use the data from the equipment interface module  34  to evaluate the system&#39;s operation and/or performance. For example, the HVAC controller  18  may compare data related to the difference in temperature (delta T) between the return air side and the discharge air side of the HVAC system  4  to a previously determined delta T limit stored in the HVAC controller  18  to determine a current operating performance of the HVAC system  4 . In other cases, the equipment interface module  34  may itself evaluate the system&#39;s operation and/or performance based on the collected data. 
       FIG. 2  is a schematic view of an illustrative HVAC control system  50  that facilitates remote access and/or control of the illustrative HVAC system  4  shown in  FIG. 1 . The HVAC control system  50  may be considered a building automation system or part of a building automation system. The illustrative HVAC control system  50  includes an HVAC controller, as for example, HVAC controller  18  (see  FIG. 1 ) that is configured to communicate with and control one or more HVAC components  6  of the HVAC system  4 . As discussed above, the HVAC controller  18  may communicate with the one or more HVAC components  6  of the HVAC system  4  via a wired or wireless communication link  20 . Additionally, the HVAC controller  18  may communicate over one or more wired or wireless networks that may accommodate remote access and/or control of the HVAC controller  18  via another device such as a smart phone, tablet, e-reader, laptop computer, personal computer, key fob, or the like. As shown in  FIG. 2 , the HVAC controller  18  may include a first communications port  52  for communicating over a first network  54 , and in some cases, a second communications port  56  for communicating over a second network  58 . In some cases, the first network  54  may be a wireless local area network (LAN), and the second network  58  (when provided) may be a wide area network or global network (WAN) including, for example, the Internet. In some cases, the wireless local area network  54  may provide a wireless access point and/or a network host device that is separate from the HVAC controller  18 . In other cases, the wireless local area network  54  may provide a wireless access point and/or a network host device that is part of the HVAC controller  18 . In some cases, the wireless local area network  54  may include a local domain name server (DNS), but this is not required for all embodiments. In some cases, the wireless local area network  54  may be an ad-hoc wireless network, but this is not required. 
     In some cases, the HVAC controller  18  may be programmed to communicate over the second network  58  with an external web service hosted by one or more external web server(s)  66 . A non-limiting example of such an external web service is Honeywell&#39;s TOTAL CONNECT™ web service. The HVAC controller  18  may be configured to upload selected data via the second network  58  to the external web service where it may be collected and stored on the external web server  66 . In some cases, the data may be indicative of the performance of the HVAC system  4 . Additionally, the HVAC controller  18  may be configured to receive and/or download selected data, settings and/or services sometimes including software updates from the external web service over the second network  58 . The data, settings and/or services may be received automatically from the web service, downloaded periodically in accordance with a control algorithm, and/or downloaded in response to a user request. In some cases, for example, the HVAC controller  18  may be configured to receive and/or download an HVAC operating schedule and operating parameter settings such as, for example, temperature set points, humidity set points, start times, end times, schedules, window frost protection settings, and/or the like from the web server  66  over the second network  58 . In some instances, the HVAC controller  18  may be configured to receive one or more user profiles having at least one operational parameter setting that is selected by and reflective of a user&#39;s preferences. In still other instances, the HVAC controller  18  may be configured to receive and/or download firmware and/or hardware updates such as, for example, device drivers from the web server  66  over the second network  58 . Additionally, the HVAC controller  18  may be configured to receive local weather data, weather alerts and/or warnings, major stock index ticker data, traffic data, and/or news headlines over the second network  58 . These are just some examples. 
     Depending upon the application and/or where the HVAC user is located, remote access and/or control of the HVAC controller  18  may be provided over the first network  54  and/or the second network  58 . A variety of remote wireless devices  62  may be used to access and/or control the HVAC controller  18  from a remote location (e.g. remote from the HVAC Controller  18 ) over the first network  54  and/or second network  58  including, but not limited to, mobile phones including smart phones, tablet computers, laptop or personal computers, wireless network-enabled key fobs, e-readers, and/or the like. In many cases, the remote wireless devices  62  are configured to communicate wirelessly over the first network  54  and/or second network  58  with the HVAC controller  18  via one or more wireless communication protocols including, but not limited to, cellular communication, ZigBee, REDLINK™, Bluetooth, WiFi, IrDA, dedicated short range communication (DSRC), EnOcean, and/or any other suitable common or proprietary wireless protocol, as desired. In some cases, the remote wireless devices  62  may communicate with the network  54  via the external server  66  for security purposes, for example. 
     In some cases, an application program code (i.e. app) stored in the memory of the remote wireless device  62  may be used to remotely access and/or control the HVAC controller  18 . The application program code (app) may be downloaded from an external web service, such as the web service hosted by the external web server  66  (e.g. Honeywell&#39;s TOTAL CONNECT™ web service) or another external web service (e.g. ITUNES® or Google Play). In some cases, the app may provide a remote user interface for interacting with the HVAC controller  18  at the user&#39;s remote wireless device  62 . For example, through the user interface provided by the app, a user may be able to change operating parameter settings such as, for example, temperature set points, humidity set points, start times, end times, schedules, window frost protection settings, accept software updates and/or the like. Communications may be routed from the user&#39;s remote wireless device  62  to the web server  66  and then, from the web server  66  to the HVAC controller  18 . In some cases, communications may flow in the opposite direction such as, for example, when a user interacts directly with the HVAC controller  18  to change an operating parameter setting such as, for example, a schedule change or a set point change. The change made at the HVAC controller  18  may be routed to the web server  66  and then from the web server  66  to the remote wireless device  62  where it may reflected by the application program executed by the remote wireless device  62 . 
     In some cases, a user may be able to interact with the HVAC controller  18  via a user interface provided by one or more web pages served up by the web server  66 . The user may interact with the one or more web pages using a variety of internet capable devices to effect a setting or other change at the HVAC controller  18 , and in some cases view usage data and energy consumption data related to the usage of the HVAC system  4 . In some cases, communication may occur between the user&#39;s remote wireless device  62  and the HVAC controller  18  without being relayed through a server such as external server  66 . These are just some examples. 
       FIG. 1  provides an example of the HVAC system  4  as it may exist within the building  2 . In some cases, there may be a desire to improve comfort control within the building  2 , such as by adding a zoning system, increasing the number of zones in an existing zoned system, and/or reconfiguring an existing zoned system. A properly configured zoning system enables more accurate control of various environmental conditions within the building  2 , such as but not limited to temperature, humidity and the like. While zoning systems can be built into an HVAC system such as the HVAC system  4  when the HVAC system  4  is initially installed within the building  2 , in some cases it can be more difficult and/or more expensive to add/retrofit zoning into an existing HVAC system in an existing building. Described herein is a system including a plurality of individually controllable dampers as well as control functionality that is configured to be easily retrofitted into an existing HVAC system such as but not limited to the HVAC system  4  shown in  FIG. 1 . The system described herein may also be incorporated into new construction. 
       FIG. 3  is a schematic illustration of an HVAC system  100  that includes a number of wireless dampers  102   a  through  102 G that are organized into a Zone A, labeled as  104 , and a Zone B, labeled as  106 . In particular, and as illustrated, the Zone A ( 104 ) includes a total of three wireless dampers  102   a ,  102   b  and  102   c , and the Zone B ( 106 ) includes a total of four wireless dampers  102   d ,  102   e ,  102   f  and  102   g . It will be appreciated that the Zone A, labeled as  104 , may include only one or two wireless dampers, or may include four or more wireless dampers. Similarly, the Zone B, labeled as  106 , may include only one or two or three wireless dampers, or may include five or more dampers. In some cases, Zone A ( 104 ) may be a first room in a building while Zone B ( 106 ) may be a second room in the same building. In some cases, Zone A ( 104 ) may be a first part of room in a building while Zone B ( 106 ) may be a second part of the same room in the same building. In some instances, Zone A ( 104 ) and Zone B ( 106 ) may represent different floors in the same building. In some instances, while a total of two zones are illustrated, it will be appreciated that a building may have a greater number of zones. 
     As illustrated, the Zone A ( 104 ) includes a wireless sensor  108   a  while the Zone B ( 106 ) includes a wireless sensor  108   b . While each Zone is illustrated as only having a single wireless sensor  108 , it will be appreciated that in some cases, a particular Zone may have two or more wireless sensors  108 . In some cases, the wireless sensor  108   a  may wirelessly communicate with one or more of the wireless dampers  102   a ,  102   b  and  102   c  that are within the Zone A ( 104 ) such that one or more of the wireless dampers  102   a ,  102   b  and  102   c  may open or close to either let additional conditioned air into the Zone A ( 104 ), or to reduce the inlet of conditioned air into the Zone A ( 104 ) in order to maintain a desired temperature, for example. In some cases, other air conditions that may be monitored and controlled include humidity, carbon dioxide, carbon monoxide, volatile organic compounds (VOCs), radon, particular matter, and others. In some cases, the wireless sensor  108  may additionally or alternatively communicate wirelessly with a thermostat  110  or other building controller (e.g. EIM) that may be considered as being an example of the HVAC controller  18  shown in  FIGS. 1 and 2 . In some cases, the thermostat  110  may directly control an HVAC system  112  that may be considered as being an example of the HVAC system  4  shown in  FIGS. 1 and 2 . In some instances, the thermostat  110  may instead communicate wirelessly or in a wired fashion with an equipment interface module (EIM)  114  that may be considered as an example of the EIM  34  shown in  FIGS. 1 and 2 . In some cases, one or more of the wireless sensors  108  may be a wired sensor that communicates with the an HVAC controller via a wired connection. 
     In some cases, each of the wireless dampers  102   a ,  102   b ,  102   c  within the Zone A ( 104 ) may open or close in unison, as directed by the thermostat  110 . In some instances, depending on a current need for conditioned air, the thermostat  110  may direct one or two of the wireless dampers  102   a ,  102   b ,  102   c  to open or close while the remaining wireless dampers  102   a ,  102   b ,  102   c  are left in their current position. Similarly, each of the wireless dampers  102   d ,  102   e ,  102   f ,  102   g  within the Zone B ( 106 ) may open or close in unison, as directed by the thermostat  110 . In some instances, depending on a current need for conditioned air, the thermostat  110  may direct one or two of the wireless dampers  102   d ,  102   e ,  102   f ,  102   g  to open or close while the remaining wireless dampers  102   d ,  102   e ,  102   f ,  102   g  are left in their current position. In some instances, as will be discussed, the selection of which wireless dampers to move may depend on relative battery levels of the wireless dampers (e.g. move those wireless dampers that have a higher remaining battery charge level). 
     In some cases, the wireless dampers  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f  and  102   g , and other wireless dampers if present, may be installed during a process of installing the HVAC system  100 . In some cases, however, the wireless dampers  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f  and  102   g , and other wireless dampers if present, may be installed into an existing HVAC system to retrofit zoning into the existing HVAC system. As noted above, a particular zone may correspond to a particular room in a building, or to a group of rooms within the building, or perhaps to a floor or level within the building. It will be appreciated that by making zones smaller, it can be easier to more accurately control environmental conditions within the building. Because the HVAC system  100  may in some cases represent a retrofit system that is installed into an existing HVAC system (such as the HVAC system  4 ), there are advantages in having each of the wireless dampers  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f  and  102   g  communicate wirelessly, to avoid having to run communication wires between each of the wireless dampers  102   a ,  102   b ,  102   c ,  102   d ,  102   e ,  102   f  and  102   g  and the thermostat  110 , for example. 
     As will be appreciated, each zone (such as the Zone  104  and the Zone  106  shown) may include one or more sensors  108  that may measure a variety of different environmental parameters such as but not limited to temperature, humidity, air quality and the like. Such sensors  108  may enable the thermostat  110  and/or the EIM  114  to operate the HVAC system  112  in a manner that enables the HVAC system  112  to maintain environmental parameters within desired ranges for each of the zones. In some cases, each zone may be controlled separately, and may for example have unique setpoints on a zone by zone basis. For example, a zone covering a portion of a building that is generally occupied during a particular time of day may have a first set of desired environmental parameter settings while another zone covering another portion of the building that is generally unoccupied during that same particular time of day may have a second set of desired environmental parameter settings that can be substantially different from the first set of desired environmental parameter settings. 
     In some cases, the HVAC system  112  may be operated in accordance with the zone of greatest demand (ZGD). The ZGD may be determined by which zone has the greatest differential between a current value for a particular environmental parameter (e.g. temperature) and a setpoint for that particular environmental parameter (e.g. temperature setpoint). In some cases, the thermostat  110  may also track historical data to help ascertain the ZGD. 
     As an example, a first zone may have a current temperature that is one degree above the current temperature setpoint. A second zone may have a current temperature that is at the current temperature setpoint. A third zone may have a current temperature that is five degrees below the current temperature setpoint. In this scenario, assuming the HVAC system  112  is in a heating mode, the third zone would be the ZGD, and the HVAC system  112  would begin providing heat. The damper(s) in the third zone would be fully open, while the damper(s) in the first zone and the second zone would likely be fully closed in this example. Over time, however, the control may be configured to converge on a set of damper positions that is largely steady state, and the control may makes only minor changes often to limited dampers to account for thermal load changes within the building that often have relatively long time constants (e.g. tens of minutes to hours). 
     In some cases, say if only one zone is demanding conditioned air (heated air, cooled air or ventilated air, for example), the dampers in the other zones may not be able to simply stay shut. It will be appreciated that in order to protect the HVAC equipment from excessive pressure and/or excessive temperature deltas, it may be necessary to provide a bypass for at least some of the conditioned air, or to open and close dampers in the other zones in accordance with a PI (proportional integral) or other control algorithm, thereby protecting the HVAC equipment while largely satisfying environmental parameter settings in each zone. This can also help with preventing high limit cycling and fan wear. 
     In some instances, the HVAC system  112  may be configured to support automatic change over (ACO), which means the system can automatically switch from heat mode to cool mode, or vice versa. This can be based on an aggregate thermal demand of the zones, or perhaps be based on the thermal demand of a majority of the zones. In some cases, ACO includes dynamic change with heat, purge, cool, purge, repeat. There are several ways of accomplishing this. One ACO example is to switch between heat and cool every twenty minutes with equipment protection. In some cases, the system can track one ZGD for heating and another ZGD for cooling. In some instances, occupancy-based priority may be given to provide comfort in occupied zones in favor of conditions within one or more unoccupied zones. 
     In some cases, the HVAC system  112  may be a forced air system (similar to  FIG. 1 ) that provides conditioned air, including heated air and/or cooled air, through a series of ducts that emanate through the building from a source of conditioned air, such as but not limited to a forced air furnace. The series of ducts provide conditioned air to a plurality of register vents that may be distributed throughout the building. In some cases, there may be a transition element known as a register boot that transitions between the duct run, which is frequently a round duct having a 6 inch or perhaps an 8 inch diameter, to the register vent, which is frequently (but not always) rectilinear in shape. In some instances, the register boot, in addition to providing a transition in shape between a round duct and a rectilinear register vent, may in some cases also provide a transition in direction. For example, a rectilinear register vent cut into a floor, with the register vent facing upwards, may be supplied with conditioned air via a round duct that runs parallel to (but underneath) the finished floor, and the corresponding register boot disposed therebetween may be configured to change the direction of the conditioned air flowing from the duct to and through the register vent. 
     One problem with retrofitting a damper system into the register vents of an existing HVAC system is the large number of damper configurations that must be produced in order to handle the wide array of register vent and register boot configurations that out on the market. Moreover, it will be appreciated that the geometry of the duct and the register boot may present difficulties in fitting a wireless damper  102   a ,  102   b ,  102   c ,  102   d ,  102   d ,  102   f ,  102   g  in position within the building&#39;s ductwork in retrofitting a zoning system into an existing HVAC system. 
       FIG. 4  provides an illustration of a portion of a duct and a register boot. The duct and the register boot are shown as being transparent, in order to illustrate particular features of a damper  102 . A portion of a duct  120  is illustrated, although it will be appreciated that in an HVAC system, the duct  120  would continue to the left, perhaps to a larger supply duct, that in turn is fed conditioned air via a forced air furnace or the like. The duct  120  may be considered as having a longitudinal axis L 1 . A register boot  122  is operably coupled to the duct  120 , and may be considered as having a longitudinal axis L 2  that is at least substantially orthogonal, or forming a 90 degree angle with, the longitudinal axis L 1  of the duct  120 . As can be seen, the register boot  122  changes the direction of the conditioned air flowing from the duct  120  into and through the register boot  122 . A register vent (not shown) is typically provided over the output  122   b  of the register boot  122 . 
     An illustrative damper  102  may be seen as being positioned within the duct  120  and the register boot  122 . The damper  102  includes a damper assembly  130  that is operably coupled to an elongated deployment member  132 . As will be discussed, the elongated deployment member  132  is flexible in at least one direction in order to use the elongated deployment member  132  to advance the damper assembly  130  through a throat of the register boot  122  and into position within the duct  120  from a position in or near the register boot  122 . 
     In some cases, the duct  120  has a circular cross-sectional profile while a register vent (not shown) has a non-circular profile. As shown in  FIG. 4 , the register boot  122  provides a transition from the circular profile to the non-circular profile. In some instances, the register boot  122  has an input  122   a  that is circular and an output  122   b  that is rectangular. In some cases, as shown, the input  122   a  faces a direction that is about 90 degrees offset from a direction that the output  122   b  faces. The elongated deployment member  132  may be bendable by an installer in at least one direction to accommodate this transition in direction. 
     In some cases, the elongated deployment member  132  may be considered as being flexible along its length in one lateral direction while being rigid (or more rigid) in an orthogonal lateral direction. In some cases, the elongated deployment member  132  has a cross-sectional profile that is much wider in one dimension and much thinner in a second direction that is orthogonal to the first dimension. For example, in some cases, the elongated deployment member  132  may have a cross-sectional profile that is at least five times wider than it is thick. In some cases, the elongated deployment member  132  may be considered as having a length sufficient to permit the damper assembly  130  to be disposed within the duct  120  upstream of the register boot  122  while a downstream end of the elongated deployment member  132  is securable to the register boot  122 . 
     In some cases, the elongated deployment member  132  may have a length that is in a range of about 1 foot to about 5 feet. In some instances, the elongated deployment member  132  may have a length that is in a range of about 2 feet to about 4 feet, or in some cases may have a length that is in a range of about 2.5 feet to about 3.5 feet. In some cases, any extra length of the elongated deployment member  132 , beyond what is needed to position the damper assembly  130  within the duct  120  and to secure a downstream end of the elongated deployment member  132  within the register boot  122  may simply be bent over into the register boot  122 , or may be cut off if desired. 
     The illustrative damper  102  also includes a control module  134  and a power module  136 . In some cases, the control module  134  and the power module  136 , each of which will be discussed in greater detail, may be configured to be secured in position in or near the register boot  122  so as to be easily reachable after removing the register vent. In some cases, the control module  134  may be operably coupled to the damper assembly  130  via two or more electrical wires (not shown). In some cases, the power module  136  may be operably coupled to the control module  134  via two or more electrical wires (not shown). 
     The control module  134  may be configured to control operation of the damper assembly  130 . In some instances, as shown, the control module  134  includes an antenna  306  (see also  FIGS. 11 and 12 ) for wireless communication (such as with the wireless sensor  108   a ,  108   b  and/or with the thermostat  110 ) that can be inserted through a hole formed in a side wall of the register boot  122  to avoid signal strength issues that could otherwise result from being inside a metal enclosure formed by the duct  120  and the register boot  122 . In some cases, the power module  136  may include replaceable batteries, so locating and reaching the power module  136  within the register boot  122  can be beneficial. 
     As illustrated, the damper assembly  130  is shown in an operational configuration in which the damper assembly  130  is secured in place within the duct  120  but is also in a configuration in which the damper assembly  130  is able to have an impact on the flow of conditioned air flowing through the duct  120  and past the damper assembly  130 . In the operational configuration, it can be seen that the damper assembly  130  is situated generally perpendicular to the elongated deployment member  132 . In the example shown, the damper assembly  130  includes a damper frame  140  and a damper blade  142  that is disposed relative to the damper frame  140 , and is configured to pivot relative to the damper frame  140  between a closed position (as illustrated) in which the damper blade  142  is at least substantially parallel (or coplanar) with the damper frame  140  (and parallel with the longitudinal axis L 1 ) and an open position in which the damper blade  142  has rotated to a position in which the damper blade  142  is at least substantially perpendicular to the damper frame  140  (and perpendicular to the longitudinal axis L 1 ). In some cases, the open position may refer to a position in which the damper blade  142  has rotated less than 90 degrees relative to the closed position shown. In some instances, the open position may refer to a position in which the damper blade  142  has rotated more than 90 degrees relative to the closed position shown. It will be appreciated that in some cases the damper blade  142  may be rotatable to a plurality of intermediate positions that are somewhere between a fully open and a fully closed position. 
     The illustrative damper assembly  130  includes a resilient seal  144  that extends radially outwardly from the damper frame  140 . When the duct  120  is round, the resilient seal  144  has an at least substantially round outer profile in order to sealingly engage an inner surface of the duct  120 . In some cases, the resilient seal  144  has a diameter that is greater than an anticipated inner diameter of the duct  120 , in order to better seal against the inner surface of the duct  120  and to accommodate any variations in the shape of the duct  120 , such as if the duct  120  is not perfectly round, or is dented. In some cases, the duct  120  may be formed of a flexible material, in which case the resilient seal  144  has to seal against a more dynamic surface than if the duct  120  is made of smooth metal. In some cases, the duct  120  may be constructed of a plastic covered spiral metal wire with an associated non-uniform inner surface. For example, for use in a duct  120  having a diameter of six inches, the resilient seal  144  may have an outer diameter of up to about six and a half or seven inches. In some cases, the resilient seal  144  may be configured to bend, fold or rollover on itself in order to consistently seal against the inner surface of the duct  120 , and to help the damper assembly  130  fit through the throat of the register boot  122  during deployment. In some cases, the resilient seal  144  may be referred to as a duct seal that is more flexible than the damper frame  140 . 
     In the example shown, the elongated deployment member  132  is coupled to a coupler  150 , which is itself rotatably engaged with an engagement feature  152  forming a portion of a damper insert arm  154 . In some cases, as will be discussed, the relative rotation between the coupler  150  and the engagement feature  152  may be limited, thereby allowing the elongated deployment member  132  to rotate relative to the damper assembly  130  during smaller rotational movement of the elongated deployment member  132  yet cause the damper assembly  130  to rotate with the elongated deployment member  132  during larger rotational movements of the elongated deployment member  132 . 
     The damper insert arm  154  is movable between the deployment configuration, in which the damper insert arm  154  is at least substantially parallel with the damper frame  140 , and the operational configuration (shown in  FIG. 4 ), in which the damper insert arm  154  is at least substantially perpendicular to the damper frame  140 . In some cases, the damper insert arm  154  is biased into the operational configuration by a biasing force, and is temporarily held against this biasing force when held in the deployment configuration. In some cases, the damper insert arm  154  may include a pair of biasing springs  156  that bias the damper insert arm  154  into the operational configuration. In some cases, as will be discussed, the damper insert arm  154  may be configured such that the damper insert arm  154  can be released from the deployment configuration, into the operational configuration, by an installer who is in an installation position that is either within or even downstream of the register boot  122 . 
     The damper assembly  130  may be considered as being configured for placement within a duct  120  of an existing ductwork system. The damper assembly (or damper)  130  may be configured to articulate from the deployment configuration, which facilitates advancing the damper  130  through the throat of the register boot  122  and into the duct  120 , to an operational configuration (as shown in  FIG. 4 ) in which the damper  130  is positioned within the duct  120  and is able to selectively control how much conditioned air supplied to the duct  120  is permitted to pass by the damper  130  and exit the register vent (not illustrated). In some cases, the damper frame  140  may be considered as having a frame periphery  160 , and the resilient seal  144  may extend radially outwardly from the frame periphery  160 . The resilient seal  144 , which may be considered to be flexible, engages the inner surface of the duct  120  when in the operational configuration. In some cases, a frictional engagement between the resilient seal  144  and an inner surface of the duct  120  helps secure the damper  130  within the duct  120 . 
     It will be appreciated that the elongated deployment member  132  facilitates advancement of the damper  130  through the register boot  122  and into the duct  120 , and moreover is configured to help retain the damper  130  in position within the duct  120  by anchoring at least a portion of the elongated deployment member  132  downstream of the damper  130 . In some cases, at least a portion of the elongated deployment member  132  may be bent into contact with a side wall of the register boot  122 , and may be secured to the side wall of the register boot  122 . This may be accessible to an installer through the output  122   b  of the register boot  122  after the register vent is removed. In some cases, the elongated deployment member  132  has an end portion  162  that is opposite where the elongated deployment member  132  is secured to the damper assembly  130 , and the end portion  162  may be configured to be secured to a wall of the register boot  122  to help hold the damper assembly  130  in the duct  120  when the damper assembly  130  is in the operational configuration. In some cases, it will be appreciated that the damper assembly  130  may be located and secured in position within the duct  120 , upstream of the register boot  122 , by an installer at an installation position within or downstream of the register boot  122 . 
     The illustrative damper assembly  130  includes a drive motor  164  that is configured to rotate the damper blade  142 , relative to the damper frame  140 , between a closed end position (illustrated in  FIG. 4 ) in which air moving through the duct  120  is restricted from flowing past the damper blade  142  and through a register vent downstream of the damper assembly  130 , and an open end position (see  FIG. 7 ) in which air moving through the duct  120  is less restricted from flowing past the damper blade  142  and through a register vent downstream of the damper assembly  130 . 
       FIGS. 5-7  show a damper assembly  131  that is similar to the damper assembly  130 , but includes a damper insert arm  155  that is different from the damper insert arm  154  of  FIG. 4 . Rather than including a pair of biasing springs  156  that secure the damper insert arm  154  to the damper frame  140 , the damper insert arm  155  in  FIGS. 5-7  is pivotably secured to the damper frame  140  via a pair of pivot points  170   a  and  170   b . A spring  172  (visible in  FIG. 7 ) is configured to bias the damper assembly  131  into the operational configuration shown in  FIGS. 6 and 7 . When the damper assembly  131  is in the deployment configuration shown in  FIG. 5 , the damper insert arm  155  is held in the deployment configuration, against the biasing force of the spring  172 , via a latch mechanism  180 . The latch mechanism  180  includes a pin  182  (visible in  FIG. 6 ) that releasably engages a corresponding cutout  184  that is formed as part of the damper insert arm  155 . In some cases, there are a pair of pins  182 , on either side of a locking structure  186 . In some cases, there are a pair of cutouts  184 , configured to releasably engage each of the pair of pins  182 . The damper assembly  131  may be moved into the deployment configuration shown in  FIG. 5  by pushing the damper insert arm  155  downward against the biasing force such that the pins  182  are able to engage the cutouts  184 . This may include temporarily moving the locking structure  186  out of the way, then releasing the locking structure  186  so that the pins  182  engage the cutouts  184 . 
     It will be appreciated that when the damper assembly  131  is in the deployment configuration, the damper assembly  131  may be more easily inserted into and through the throat of the register boot  122  and into position within the duct  120 . One feature that helps with insertion is the physical configuration of the damper frame  140  and the damper blade  142 . Looking at the damper frame  140 , as visible for example in  FIG. 6 , the damper frame  140  including the frame periphery  160  has an outer frame periphery  160   a  and an inner frame periphery  160   b . The resilient seal  144  extends radially outwardly from the outer frame periphery  160   a . As will be discussed, the inner frame periphery  160   b  provides a seal against the damper blade  142  when the damper blade is in the closed position, as shown for example in  FIGS. 5 and 6 . In some cases, as illustrated, the frame periphery  160  (which can include the outer frame periphery  160   a  and/or the inner frame periphery  160   b ) has an at least substantially obround shape. 
     An obround shape is a two-dimensional shape that includes a rectangle with semicircles at either end. This is also known as a stadium shape and/or a disco rectangle. A shape that is substantially obround in shape refers to a rectangle that has two curved ends spanning a pair of parallel straight or at least substantially straight sides, but with each curved end only representing a portion of a circle, rather than a full semicircle. This shape is illustrated for example in  FIG. 6 , where the damper frame  140  may be seen as having a first straight side  190 , a second straight side  192  that is at least substantially parallel to the first straight side  190 , a first curved side  194  spanning between the first straight side  190  and the second straight side  192 , and a second curved side  196  opposite the first curved side  194  and spanning between the first straight side  190  and the second straight side  192 . In some cases, as shown, the first straight side  190  and the second straight side  192  both have a length that is greater than a distance (measured orthogonally to the length) between the first straight side  190  and the second straight side  192 . The damper blade  142  may be seen as having a damper blade periphery  198  that is complementary to a shape of the inner frame periphery  160   b , and thus is also at least substantially obround in shape. In some cases, the damper blade  142  may be considered as having a first dimension across the damper blade  142  in a first direction, and a second dimension across the damper blade  142 , orthogonal to the first direction, that is less than the first dimension. The resilient seal  144 , however, may be seen as having a circular or at least substantially circular shape in order to seal against an inner surface of the duct  120 . 
     Looking for example at  FIG. 5 , it will be appreciated that the at least substantially obround shape of the damper frame  140  and the damper blade  142 , in combination with the orientation of the damper assembly  131  relative to the elongated deployment member  132  maximizes an overall area of the damper blade  142 , thus maximizing possible air flow through the damper assembly  131 , while minimizing the effective deployment configuration profile of the damper assembly  131  in order to facilitate advancement of the damper assembly  131  into and through the throat of the register boot  122  and into the duct  120 . As will be appreciated, the resilient seal  144  is sufficiently flexible to bend out of the way as the damper assembly  131  is advanced through the throat of the register boot  122  and into the duct  120 . In some cases, the duct  120  may include a balancing damper, and the effective deployment configuration profile may assist in being able to advance the damper assembly  131  through and past any such balancing damper. It will be appreciated that any balancing dampers may be manually moved to a fully open position before the damper assembly  131  is advanced through the balancing damper. 
     With reference to  FIGS. 6 and 7 , the inner frame periphery  160   b  defines an air flow aperture  200 . The damper blade  142  is pivotably secured to the damper frame  140  at a pivot point  202 , and is pivotable between a closed position (see  FIG. 6 ) in which the damper blade  142  seals against the damper frame  140  and the damper blade  142  substantially blocks air flow through the air flow aperture  200 , and an open position (see  FIG. 7 ) in which the damper blade  142  does not seal against the damper frame  140  and allows air flow through the air flow aperture  200 . In some cases, the seal between the damper blade  142  and the damper frame  140  may be considered to be an inner seal while a seal between the resilient seal  144  and an inner surface of the duct  120  may be considered as being an outer seal. 
       FIG. 8  is a perspective view of the damper assembly  131  with the resilient seal  144  removed to reveal that in some cases, the damper frame  140  includes an upstream damper frame member  140   a  and a downstream damper frame member  140   b  that are secured together. It will be appreciated that in some cases, the resilient seal  144  may include an inner portion that is secured (e.g. clamped) between the upstream damper frame member  140   a  and the downstream damper frame member  140   b . In some cases, for example, the upstream damper frame member  140   a  may be secured to the downstream damper frame member  140   b  via a plurality of screws  141 . In other cases, the upstream damper frame member  140   a  may engage the downstream damper frame member  140   b  in a snap-fit connection, or the upstream damper frame member  140   a  may be adhesively secured to the downstream damper frame member  140   b.    
     In some cases, when the damper blade  142  is in the closed position, at least part of the damper blade  142  seals against the downstream damper frame member  140   b . In some instances, the damper frame  140 , including the downstream damper frame member  140   b , may be considered as being rigid, and thus providing a consistent seal surface against which the damper blade  142  (or a damper blade periphery  198 ) may seal when in the closed position. In some cases, the outer frame periphery  160   a  may be considered as defining a first shape while an outer periphery  144   b  (shown in  FIG. 6 ) defines a second shape. In some cases, the first shape may be obround while the second shape may be round. Alternatively, the first shape may be obround while the second shape may be rectangular. In some cases, as shown for example in  FIG. 8A , the damper frame may instead be a single structure. 
       FIG. 8A  is a side perspective view of a damper assembly  133  that includes a unitary damper frame member  140   c  and a resilient seal  144   a  that is molded into the unitary damper frame member  140   c . In particular, and as shown in  FIG. 8B , the unitary damper frame member  140   c  includes a seal securement member  140   d  that extends radially from the unitary damper frame member  140   c  so that the resilient seal  144   a  may be molded around and into the seal securement member  140   d .  FIG. 8C  shows the resilient seal  144   a  absent the unitary damper frame member  140   c . As can be seen, the resilient seal  144   a  includes an engagement region  140   e . As can be seen, there is a complementary relationship between the seal securement member  140   d  of the unitary damper frame member  140   c  and the engagement region  140   e  of the resilient seal  144   a  that serves to lock the resilient seal  144   a  to the unitary damper frame member  140   c.    
       FIG. 8A  also illustrates an electrical control cable  188   a  that extends through the locking structure  186 . In some cases, the electrical control cable  188   a  may extend between the control module  134  and the damper assembly  133  in order to provide control commands and/or electrical power in an appropriate polarity to actuate the damper assembly  133  towards a more open position or a more closed position, depending on polarity. As will be discussed with respect to  FIG. 9 , when the damper assembly  133  is in the deployment configuration, in which the damper assembly  133  is rotated about 90 degrees relative to the operation configuration shown in  FIG. 8A , pulling on the electrical control cable  188   a  can provide a lateral force on the locking assembly  186 , thereby moving the locking assembly  186  sufficiently to release the damper assembly  133  from the deployment configuration such that the damper assembly  133  may regain the operation configuration. 
       FIG. 9  is a perspective view of the damper assembly  131  in the deployment configuration. As discussed, the illustrative damper assembly  131  includes a locking structure  186  bearing one or more pins  182  that releasably engage a corresponding one or more cutouts  184  formed in the damper insert arm  155 . It will be appreciated that once the damper assembly  131  has been inserted through the register boot  122  and into the duct  120 , the latch mechanism  180 , including the locking structure  186 , will be in the duct  120 , and thus not easily reached from an installer position within or outside of the register boot  122 . In some cases, the latch mechanism  180  may be remotely released from the deployment configuration to the operation configuration from an installer position within or outside of the register boot  122 . 
     In some cases, an elongate release mechanism  188  may extend from a position near a far end of the elongated deployment member  132 , for example, to a position where the elongate release mechanism  188  may engage the locking structure  186  and/or pass through the locking structure  186 . By pulling proximally on the elongate release mechanism  188 , because the elongate release mechanism  188  extends into the locking structure  186 , this exerts a force orthogonally to the latch mechanism  180  and in particular orthogonal to the locking structure  186 , thereby causing the locking structure  186  to pivot along a pivot point  186   a  in the direction indicated by an arrow  189 . This moves the pins  182  out of engagement with the cutouts  184 , and thus the damper insert arm  155  is free to move back into the operational configuration, driven by the biasing force applied by the spring  172 . In some cases, the elongate release mechanism  188  may be an elongate rod that engages the locking structure  186 . In some cases, the elongate release mechanism  188  may be an electrically conductive cable providing power and/or control commands to the damper assembly  131 . 
     As seen in  FIG. 9 , the damper blade  142  may be considered as having an axis of rotation L 3  that intersects the drive motor  164 . In some cases, the axis of rotation L 3  may be considered as being at least substantially parallel with the first straight side  190  and/or the second straight side  192 . In some cases, the drive motor  164  includes (see  FIG. 7 ) a drive motor body  210  having a first end  212  and an opposing second end  214 . The first end  212  may be secured to the damper frame  140  while the second end  214  may extend towards the damper blade  142 . In some cases, the damper blade  142  includes a cutout  216  that is configured to accommodate at least part of the drive motor body  210  when the damper blade  142  rotates relative to the drive motor  164  and relative to the damper frame  140 . In some cases, the second end  214  of the drive motor body  210  may include a drive shaft extending from the second end  214 . 
     As noted above, the elongated deployment member  132  may be coupled to the coupler  150 . As can be seen for example in  FIG. 10 , which is a perspective view of the damper assembly  131 , the coupler  150  may include a first portion  250  that is configured to engage an end of the elongated deployment member  132  and a second portion  252  that is configured to extend into the engagement feature  152  of the damper insert arm  155  and rotate relative to the engagement feature  152 . The first portion  250  includes a recess  270  that is configured to accommodate an end of the elongated deployment member  132  as well as a locking feature  272  that engages a corresponding aperture within the elongated deployment member  132  to lock the elongated deployment member  132  to the coupler  150 . In some cases, the locking feature  272  includes a living hinge that enables the locking feature  272  to flex when a first end of the elongated deployment member  132  is inserted into the recess  270 . 
     In some cases, there may be a desire to permit limited rotation of the elongated deployment member  132  relative to the damper assembly  131  while not permitting further relative rotation. This may be useful when deploying the damper assembly  131  through the register boot  122  and into the duct  120 . Because the elongated deployment member  132  is flexible in at least one lateral direction while being more rigid in an orthogonal lateral direction, permitting some rotation enables the installer to flex or bend the elongated deployment member  132  while inserting the damper assembly  131  into the duct  120 . Because the installer may also wish to be able to rotate the damper assembly  131  relative to the register boot  122  and/or duct  120 , the damper assembly  131  may be configured to limit such rotation. 
     In some cases, as shown, the second portion  252  may include a rotation limit feature  254  that extends outwardly from a surface  256  of the second portion  252 . In some cases, as shown, the engagement feature  152  includes a first axially aligned feature  260  and a second axially aligned feature  262  that is parallel with the first axially aligned feature  260 . The rotation limit feature  254  is configured to be able to rotate freely between the first axially aligned feature  260  and the second axially aligned feature  262 , but is configured to engage the first axially aligned feature  260  if rotated too far in a first direction and to engage the second axially aligned feature  262  if rotated too far in a second, opposing, direction. Accordingly, the elongated deployment member  132  is permitted to rotate a certain amount relative to the damper assembly  131 , while further rotation of the elongated deployment member  132  causes rotation of the damper assembly  131 . 
     As an example, the elongated deployment member  132  may be permitted to rotate up to 90 degrees relative to the damper assembly  131  before the damper assembly  131  rotates with the elongated deployment member  132 . In some cases, the rotation limit feature  254  may run into one of the first axially aligned feature  260  and the second axially aligned feature  262  when the coupler  150  is rotated counter clockwise to a 0 degree position and the rotation limit feature  254  may run into the other of the first axially aligned feature  260  and the second axially aligned feature  262  when the coupler  150  is rotated clockwise to a 90 degree position. This is just an example, as of course clockwise and counter-clockwise depend on a relative reference frame. 
       FIG. 11  is a perspective view of the illustrative control module  134  while  FIG. 12  is an exploded perspective view thereof. As seen in  FIG. 11 , the control module  134  may include a control module housing  300 . In some cases, the control module housing  300  may include a first housing portion  302  and a second housing portion  304 . The control module housing  300  may be configured to be secured to the register boot  122  and in some cases may include a curved portion in order to accommodate a corresponding curved region of the register boot  122 . An antenna  306  extends from the control module housing  300  and may be configured, for example, to extend through an opening drilled through a wall of the register boot  122  such that the antenna  306  is at least partially positioned exterior to the register boot  122 . 
     The illustrative control module  134  includes a control circuit board  308 . A power jack  310  that is configured to accommodate a power supply cable providing power to the control module  134  is operably coupled to the control circuit board  308 . A control jack  312  that is configured to accommodate a control cable that operably couples the control module  134  to the damper assembly  131  is operably coupled to the control circuit board  308 . In some cases, as illustrated, the control module  134  includes a CONNECT button  314  that engages a switch  316  disposed on the control circuit board  308 . In some cases, the CONNECT button  314  may be used in pairing the control module  134  with the thermostat  110  ( FIG. 3 ), an EIM  114  ( FIG. 3 ) or another control module via a wireless network connection (e.g. ZigBee, REDLINK™, Bluetooth, WiFi, IrDA, dedicated short range communication (DSRC), EnOcean, and/or any other suitable common or proprietary wireless protocol). In some cases, the CONNECT button  314  may include an LED or other light source that can be selectively illuminated when connecting the control module  134  to other devices. 
     As noted, the illustrative control module  134  is intended to be secured relative to the register boot  122 , such as along a wall of the register boot  122 , proximate a hole drilled or otherwise formed in the register boot  122  to permit the antenna  306  to extend therethrough. In some cases, the control module  134  may include one or more magnets to provide an easy way to secure the control module  134  relative to the register boot  122 . In some cases, as illustrated, the control module  134  includes a mechanical locking feature  320  having a series of angled fins  322  that permit the antenna  306  (and the mechanical locking feature  320 ) to be inserted through a hole drilled through a wall of the register boot  122  but that resist subsequent withdrawal of the control module  134 . The mechanical locking feature  320  may be formed of a resilient polymer, and may be configured to help seal the hole in the wall of the register boot  122  against air loss. In some cases, a magnet  324  may be arranged concentrically with the antenna  306 . In some cases, the antenna  306  may be flexible to bend or deflect when encountering an obstacle exterior to the register boot  122 . 
       FIG. 12A  is a perspective view of an illustrative control module  134   a  that is similar to the control module  134 , but varies in how the control module  134   a  is secured relative to the register boot  122 . A flexible grommet  320   a  may be inserted into the hole formed in the wall of the register boot  122 . The antenna  306  may be inserted through a lumen  321  extending through the flexible grommet  320   a . In some cases, as shown, the antenna  306  may include an anchoring plug  325  is secured relative to the antenna  306 , and includes an annular recess  327 . When the antenna  306  is inserted through the lumen  306 , the anchoring plug  325  extends into the lumen  321  such that the annular recess  327  engages one or more tabs  329  formed within a side wall of the lumen  321 . As a result, the anchoring plug  325 , and hence the control module  134   a , is secured in place. In some cases, the control module  134   a  may be removed from the flexible grommet  320   a  and reinstalled, if desired. 
       FIG. 13  is a schematic block diagram of the illustrative control module  134 . As can be seen, the control module  134  includes on the control circuit board  308  a transceiver  330  for sending and/or receiving commands and/or information. For example, the transceiver  330  may: (1) receive instructions communicated from a remote building controller (e.g. the thermostat  110  and/or the EIM  114  of  FIG. 3 ) such as an open command, a close command, a move to percent open command, an activate buzzer command, etc.; (2) receive sensor data from one or more remote sensors (e.g. remote temperature sensors  108  of  FIG. 3 ), such as temperature, humidity, etc.; and/or (3) transmit certain information to a remote building controller (e.g. the thermostat  110  and/or the EIM  114  of  FIG. 3 ) such as current damper position, battery level, signal strength, sensed noise level, sensed temperature, etc. These are just examples. The transceiver may be compatible with any suitable wireless protocol, such as ZigBee, REDLINK™, Bluetooth, WiFi, IrDA, dedicated short range communication (DSRC), EnOcean, and/or any other suitable common or proprietary wireless protocol. In some cases, the transceiver  330  has a lower power sleep mode and a higher power send/receive mode. To help reduce power consumption, the control module  134  may be configured to place the transceiver  330  in the lower power sleep mode, and only intermittently or periodically wake up the transceiver  330  to send and/or receive data before returning to the lower power sleep mode. 
     The illustrative control module  134  also includes on the control circuit board  308  a controller or processor for generating air damper movement commands in response to the received instructions. The air damper movement commands may be sent to the damper assembly  131  via a control cable that operably couples the control module  134  with the damper assembly  131 . The control cable may connect to control jack  312  of the control module  134 . The control cable may not only deliver the damper movement commands to the damper assembly  131 , but may also deliver power to the damper assembly  131 . In some instances, the control module  134  may not generate damper movement commands per se, but may instead simply provide power to the damper assembly  131 , in either a forward or reverse polarity, in order to actuate a damper drive motor. 
     The antenna  306  may be coupled to the control circuit board  308  in a variety of ways.  FIGS. 14 through 18  provide illustrative but non-limiting examples of ways in which the antenna  306  may be coupled to the control circuit board  308 , as well as providing examples of antenna configuration.  FIG. 14  is a schematic illustration of an assembly  350  that includes an antenna  306   a . It will be appreciated that this is shown schematically, without any housing about the circuitry shown. In some cases, as illustrated, the antenna  306   a  includes a flexible wire  352  that is operably coupled to a radio board  354 . In some cases, the radio board  354  may be considered as an example of the control circuit board  308  shown in  FIGS. 12 and 13 . The flexible wire  352  may be any length, although in some cases the antenna  306   a  may be a′/4 wavelength of the operable center frequency, and in particular cases the flexible wire may have a length of about 8.2 centimeters (cm). This is just an example and will depend on the frequency band that is intended to be used for communication. In some instances, the radio board  354  may be a separate board or component that is operably coupled to the control circuit board  308 . The flexible wire  352  may be soldered to the radio board  354 . In some cases, as illustrated, the flexible wire  352  may instead be secured relative to the radio board  354  via a pressure contact  356 , which in some cases may provide a faster, less expensive connection. In some cases, the radio board  354  may include a spring finger  362  that is made of an electrically conductive material such as a metal and that extends from the radio board  354  and is configured to ground the radio board  354  to the metal of the register boot  122  when the control module  134  is secured to the metal of the register boot  122 . 
     The illustrative antenna  306   a  includes a polymeric boot  358  that protects the flexible wire  352  as well as electrically insulates the flexible wire  352  from the register boot  122  and other objects. It will be appreciated that the antenna  306   a , by virtue of including the flexible wire  352  as well as the polymeric boot  358 , is itself flexible, and is able to bend or deflect if the antenna  306   a  runs into an object when inserted through an aperture  360  formed in the register boot  122 . In some cases, the housing (not shown) may include guides that help prevent the antenna  306   a  from bending far enough to interfere with the pressure contact  356 . 
       FIG. 15  is a schematic illustration of an assembly  370  that includes an antenna  306   b . It will be appreciated that this is shown schematically, without any housing about the circuitry shown. In some cases, as illustrated, the antenna  306   b  includes a flexible coil  372  that is operably coupled to the radio board  354 . In some cases, the radio board  354  may be considered as an example of the control circuit board  308  shown in  FIGS. 12 and 13 . The flexible coil  372  may be any suitable length. In some instances, the radio board  354  may be a separate board or component that is operably coupled to the control circuit board  308 . The flexible coil  372  may be soldered to the radio board  354 . In some cases, as illustrated, the flexible coil  372  may instead be secured relative to the radio board  354  via the pressure contact  356 , which in some cases may provide a faster, less expensive connection. The illustrative antenna  306   b  includes a polymeric boot  374  that helps protects the flexible coil  372  as well as electrically insulating the flexible coil  372  from the register boot  122  and/or other objects. It will be appreciated that the antenna  306   b , by virtue of including the flexible coil  372  as well as the polymeric boot  374 , is itself flexible, and is able to bend or deflect if the antenna  306   b  runs into an object when inserted through an aperture  360  formed in the register boot  122 . In some cases, the housing (not shown) may include guides that help prevent the antenna  306   b  from bending far enough to interfere with the pressure contact  356 . 
       FIG. 16  is a schematic illustration of an assembly  380  that includes an antenna  306   c . It will be appreciated that this is shown schematically, without any housing about the circuitry shown. In some cases, as illustrated, the antenna  306   c  is a PCB (printed circuit board) antenna, and may be considered as being implemented on a PCB  382 . The PCB  382  may be a rigid PCB or a flex circuit. In the example shown, a polymeric boot  384  covers and protects the PCB  382 . In some cases, the radio board  354  may be considered as an example of the control circuit board  308  shown in  FIGS. 12 and 13 , although in this case the radio board  354  has been rotated to be parallel with the antenna  306   c . Use of a PCB antenna may mean that a slot needs to be cut into the register boot  122 , rather than a round hole. In some cases, the slot may be about 1 cm in length, although this is just an example. 
       FIG. 17  is a schematic illustration of an assembly  390  that includes an antenna  306   d . It will be appreciated that this is shown schematically, without any housing about the circuitry shown. In some cases, as illustrated, the antenna  306   d  includes a flexible wire  392  that is operably coupled to the radio board  354 . In some cases, the radio board  354  may be considered as an example of the control circuit board  308  shown in  FIGS. 12 and 13 , and as seen includes the power jack  310  and the control jack  312 . In some instances, the radio board  354  may be a separate board or component that is operably coupled to the control circuit board  308 . The flexible wire  392  may be soldered to the radio board  354 . The illustrative antenna  306   d  includes an electrically insulating member  394  at a terminal end thereof, as well as an electrically insulating member  396  that also seals against air flow where the flexible wire  392  exits the register boot  122 . In some cases, the antenna  306   d  may include an electrically insulating layer or tube that is disposed along the length of the flexible wire  392  to electrically isolate the flexible wire  392  from the register boot  122  and/or other objects. 
     In some cases, as illustrated, the radio board  354  includes a ground plane  398 . The ground plane  398  may be electrically coupled. i.e., grounded, to the metal register boot  122  via a screw  400  that passes through the ground plane  398  and into a hole  360  that is formed in the metal register boot  122 . The screw  400  also serves to secure the control module  134  in position relative to the metal register boot  122 . In some cases, there is an enclosure standoff  402  that helps to support the screw  400 . It will be appreciated that the antenna  306   d  is flexible, and thus is able to bend or deflect if the antenna  306   d  runs into an object when inserted through the aperture  360  formed in the register boot  122 . 
       FIG. 18  is a schematic illustration of an assembly  410  that includes the control module  134  and the power module  136  disposed within the register boot  122 . As illustrated, a control cable  412  extends between the damper assembly  130  (or the damper assembly  131 ) and a control jack  312  of the control module  134 . Also, a power cable  414  extends between a power module  136  and a power jack  310  of the control module  134 . In some cases, as illustrated, the power module  136  may be held in place on a wall of the register boot  122  via a magnet  416 . Alternatively, a power cable  414   a  may extends between a plug-in transformer  136   a  and the power jack  310  of the control module  134 . The plug-in transformer  136   a  may be used, for example, if there is a conveniently located electrical receptacle sufficiently near the particular register vent. 
     The illustrative control module  134  includes a housing  418  that has a curved surface  420  for potential installation on a curved surface such as a curved register boot  122 . A hollow screw  422  may be used to electrically ground and physically secure the control module  134  to the metal register boot  122  while securing the control module  134  to the register boot  122 . When so provided, the hollow screw  422  may be configured to accommodate an antenna wire  424  extending outwardly from the control module  134  and through the hollow screw  422 . A sheath  426  may extend over the antenna wire  424  and serves to electrically insulate the antenna wire  424  from the register boot  122  and/or other objects. In some cases, the antenna wire  424  and the sheath  426  are sufficiently flexible to bend or deflect to accommodate obstacles, such as but not limited to a joist or board  428  that is adjacent the register boot  122 . 
       FIG. 19  is a schematic block diagram of a damper system  500  that may be configured for installation in an existing duct system of a building. The illustrative damper system  500  may be installed in a duct that is providing conditioned air through a register boot to a register vent. The illustrative damper system  500  includes a damper assembly  502  that is configured to be disposed within the duct (such as the duct  120 ). The damper assembly  502  includes a damper blade  504  that is movable between a closed end position and an open end position. In some cases, as illustrated, the damper blade  504  is actuated via a damper motor  506  turning a shaft  508  that also forms a part of the damper assembly  502 . A control module  510 , which may be considered as an example of the control module  134 , is configured to be operably coupled to the damper assembly  502 . The control module  510  includes a control module housing  512  and a controller  514  that is disposed within the control module housing  512  and that regulates operation of the damper assembly  502 . In some cases, the control module housing  512  may be configured to be secured remote from the damper assembly  502  at an accessible location such as behind the register vent and within the register boot  122 . 
     A power supply  516  may be operably coupled to the control module  510 . In some cases, the power supply  516  may be disposed within a power supply housing that is remote from the control module  510 , and is operably coupled to the control module  510  via a power cable. The power supply housing may, for example, be configured to be secured to the register boot  122  when the damper assembly  502  is deployed in the duct  120 . In some cases, the power supply  516  may include one or more non-rechargeable batteries. In some cases, the power supply  516  may be part of the control module  510  and may be contained within the control module housing  512 . 
     In some cases, the control module  510  includes a transceiver  518  that is disposed within the control module housing  512  and that is operably coupled with the controller  514 . The controller  514  may be configured to, for example, monitor a remaining energy level of the power supply  516 , and to transmit a first low battery message via the transceiver  518  when the remaining energy level drops to a first energy threshold. In some instances, the controller  514  may monitor voltage as an indication of remaining energy. In some cases, the controller  514  may transmit via the transceiver  518  a low battery message to a remote device such as the thermostat  110  ( FIG. 3 ). When the remaining energy level drops to a second energy threshold that is lower than the first energy threshold, the controller  514  may be configured to instruct the damper assembly  502  to move to a predetermined position and to transmit a second low battery message via the transceiver  518 . In some cases, if the remaining energy level drops to a third energy threshold that is lower than the second power threshold, the controller  514  may be further configured to conserve the remaining battery power by no longer transmitting a low battery message via the transceiver  518  and keep the damper assembly  502  at the predetermined position. In some cases, if the remaining energy level drops to a third energy threshold lower than the second energy threshold, the controller  514  may also stop listening for transmitted messages. In some cases, the third energy threshold may be set at or above an energy level at which point an alkaline battery may begin to offgas. This is just an example. 
     In some cases, the controller  514  may determine a default damper position that is a calculated value that is based at least in part upon a history of requested damper positions. For example, if a particular damper has been closed for thirty days, it is likely appropriate to leave it closed when the corresponding power supply becomes depleted. In some cases, the controller  514  may look at seasonal data, and/or may take the calendar into account. For example, in the summer, a damper system  500  that is located upstairs may default to an open position in the summer but may default to a closed position in the winter. This is merely illustrative, as a number of different possibilities are possible. In some cases, when the remaining energy level drops to the second energy threshold, the controller  514  determines the predetermined position in accordance with a history of damper positions over a period of time ending when the energy level dropped to or below the second energy threshold. In other words, the predetermined position may be based upon a most likely or most common previous damper position for the particular damper. 
     In some cases, the controller  514  may make these calculations and determinations. In some instances, these calculations may instead be made at the thermostat  110  ( FIG. 3 ), or even by a cloud-based server. When so provided, rather than defaulting to the open end position, the controller  514  may instruct the damper assembly  502  to move to the calculated default damper position when the remaining energy level of the power supply  516  drops to the second power threshold. In some cases, the controller  514  may also be configured to provide a beep or other noise to help an individual locate the particular damper system  500  having a low battery situation, using a noise enunciator or a speaker, for example. In some instances, the controller  514  may do so in response to a request from an application running on a mobile device such as but not limited to a smartphone, for example. 
     In some cases, the controller  514  may be configured to receive one or more control commands from a remote building controller via the transceiver  518 , and to regulate operation of the damper assembly  502  based at least in part on the one or more control commands. In some instances, the controller  514  may be configured to regulate operation of the damper assembly  502  by controlling a position of the damper blade  504  of the damper assembly  502 , and to change the position of the damper blade  504  of the damper assembly  502  less frequently when the remaining energy level is less than the first power threshold than when the remaining energy level is greater than the first power threshold in order to reduce power consumption by the damper assembly  502 . 
     In some cases, there may be a plurality of individual damper systems  500  installed in a single building, and in some cases the individual damper systems  500  may cooperate in trying to compensate for a particular damper system  500  having an extremely low power supply, for example, or may utilize a particular damper system  500  having a relatively higher remaining power supply to take over more of the responsibility for maintaining thermal control within a zone or within the building.  FIG. 20  shows a retrofit zoning system  520  configured for use in zoning an HVAC system of a building. The illustrative HVAC system includes a network of ducts providing conditioned air to each of a plurality of register vents. As can be seen, the retrofit zoning system  520  includes a plurality of damper systems  500   a ,  500   b ,  500   c ,  500   d . While a total of four damper systems are shown, it will be appreciated that this is merely illustrative, as any number of damper systems may be included. Each of the damper systems  500   a ,  500   b ,  500   c ,  500   d  may be considered as including the structure and functionality of the damper system  500  shown in  FIG. 19 . 
     When one of the controllers  514  detect a remaining energy level that has dropped to or below a first energy threshold, that controller  514  is configured to transmit a first low battery message via the transceiver  518  operably coupled to that controller  514 . In some cases, when one of the controllers  514  detect a remaining energy level that has dropped to or below a second energy threshold lower than the first energy threshold, that controller  514  may be configured to instruct the corresponding damper assembly  502  to move to the predetermined position and to transmit a second low battery message via the corresponding transceiver  518 . 
     When one of the controllers  514  detects a remaining energy level that has dropped to or below a third energy threshold lower than the second power threshold, that controller  514  may be configured to stop transmitting a low battery message via the corresponding transceiver  518  and to go into a low power state. It may be desirable to preserve the remaining battery level of the battery above a battery leakage threshold for an extended period of time. Once the battery level falls below the battery leakage level, the battery may begin to leak and possibly cause damage to the power supply  516 . For example, the third energy threshold may be set at an energy level that is still above the point at which an alkaline battery may start to offgas. 
     In some cases, when one of the controllers  514  detects a remaining energy level that has dropped to or below a first power threshold, that controller  514  may be configured to change the position of the damper blade  504  of the corresponding damper assembly  502  less frequently than when the remaining energy level is detected to be above the first energy threshold in order to reduce power consumption by the damper assembly  502 . In some cases, if one of the controllers  514  detects that the remaining energy level of the corresponding power supply  516  has dropped to or below a first energy threshold, that controller may transmit a first low battery message and the retrofit zoning system may be configured to make positional changes to one or more of the other damper blades  504  in order to reduce a need for at least some positional changes of the damper blade  504  corresponding to the damper assembly  502  having the low battery condition, thereby helping to conserve remaining power in that particular power supply  516 . 
     In some cases, when one of the controllers  514  that is assigned to a first HVAC zone detects a remaining energy level that has dropped to or below a first energy threshold, the retrofit zoning system may attempt to control the first HVAC zone by regulating the operation of one or more of the other damper assemblies  500   a ,  500   b ,  500   c ,  500   d  that have a remaining energy level that is above the first energy threshold in order to reduce power consumption by the particular damper assembly  500   a ,  500   b ,  500   c ,  500   d  with a low battery condition. In some case, the retrofit zoning system may attempt to control the first HVAC zone by more aggressively regulating the operation of one or more other of the plurality of damper systems  500   a ,  500   b ,  500   c ,  500   d  that are also assigned to the first HVAC zone and that have a remaining energy level that is above the first power threshold. Put another way, the retrofit zoning system may attempt to control the first HVAC zone by expending more energy adjusting the operation of one or more of the other of the plurality of damper systems  500   a ,  500   b ,  500   c ,  500   d  that are also assigned to the first HVAC zone. 
       FIG. 21  is a schematic block diagram of a damper assembly  530  that is configured for placement within a duct of an existing ductwork system, wherein the duct supplies conditioned air through a register boot to a register vent within a room. The illustrative damper assembly  530  includes a damper blade  532  that is movable between a closed end position in which air moving through the duct is restricted from flowing past the damper blade  532  and through the register vent, and an open end position in which air moving through the duct is less restricted from flowing past the damper blade  532  and through the register vent. A damper motor  534  is operably coupled to the damper blade  532  via a shaft  536 , and the damper motor  534  is configured to move the damper blade  532  between the closed end position and the open end position. 
     In some cases, the damper assembly  530  includes a damper frame  538 , where the damper blade  532  is rotatably secured relative to the damper frame  538 . When in the closed end position, the damper blade  532  may be considered as having a contact region (such as the damper blade periphery  198  referenced in  FIG. 6 ) that engages the damper frame  538 . When in the open end position, the contact region of the damper blade  532  is rotated away from the damper frame  538 . In some cases, the damper blade  532  and the damper frame  538  are both plastic, and while not illustrated in  FIG. 21 , the damper assembly  530  may further include a flexible member extending outward from the damper frame  538  to form a seal with at least part of an inside surface of the duct. The resilient seal  144  discussed above may be considered as being an example of such a flexible member. In some cases, the damper assembly  530  may include one or more bypass channels that permit a small amount of air to flow past the damper blade  532  even when the damper blade  532  is closed. When provided, the one or more bypass channels may be provided in the flexible member, the damper frame, the damper blade or some combination of these components. 
     In some cases, the damper assembly  530  may include a microphone  540  for providing an output signal that is representative of sounds sensed by the microphone  540 . A control module  542 , which may be considered as being an example of the control module  134 , is operably coupled to the damper motor  534  and to the microphone  540 . In some cases, the control module  542  may be configured to control operation of the damper motor  534  based at least in part on the output signal provided by the microphone  540 . In some cases, for example, the control module  542  may be configured to control operation of the damper motor  534  to move the damper blade  532  to a more open position when a whistle sound is sensed by the microphone  540 . In some cases, opening the damper blade  532  may reduce and/or eliminate noises otherwise made by air flowing past a partially closed damper blade  532 , for example. 
     In some instance, the control module  542  may be configured to control operation of the damper motor  534  to reduce a frequency of positional changes to the damper blade  532  when a sound indicating occupancy of the corresponding room/zone is sensed by the microphone  540 . Reducing a number of times the damper blade  532  is moved, particularly when the room is occupied, can translate into less noticeable noise for occupants in the room. In some instances, the control module  543  may be configured to store an occupancy schedule that includes periods of occupancy and periods of non-occupancy. The occupancy schedule may be built based at least in part on a history of sounds sensed by the microphone  540 . In some cases, the control module  542  may be configured to control operation of the damper motor  534  in a first mode that reduces noise caused by the damper assembly  530  during the periods of occupancy of the occupancy schedule, and to control operation of the damper motor  534  in a second mode during the periods of non-occupancy. In some cases, the control module  542  may be configured to store a sleep schedule that defines one or more sleep periods, and the control module  542  may be configured to control operation of the damper motor  534  to reduce noise caused at least in part by the damper assembly  530  during the one or more sleep periods, regardless of any sounds detected or not detected by the microphone  540 . 
     In some cases, the control module  542  may not include the microphone  540 , and the control module  542  may be configured to make less noise during periods of time in which occupants are expected to be asleep, and may be configured to make more noise during periods of time in which occupants are expected to be awake, or even expected to be out of the building. In some cases, when in the first mode, the control module  542  may operate the damper motor  534  to move the damper blade  532  at a slower speed in order to reduce noise generation caused by the damper motor  534 , and in the second mode, the control module  542  may operate the damper motor  534  to rotate the damper blade  532  at a faster speed in order to reduce drive time and possibly reduce power consumption. In some cases, when in the first mode, the control module  542  may operate the damper motor  534  less frequently, and in the second mode, the control module  542  may operate the damper motor  534  more frequently. 
     In some cases, the damper assembly  530  may also include a sound generator  544  that is operably coupled to the control module  542 . In some instances, the control module  542  may be configured to cause the sound generator  544  to provide active noise cancellation for at least some of the sounds sensed by the microphone  540 . The control module  542  may also be configured to provide white noise via the sound generator  544 . In some cases, the control module  542  may play music, or relaxing sounds, via the sound generator  544 . These are just examples. In some cases, the control module  542  may provide a beep or buzzer sound via the sound generator  544  to help a user locate the damper assembly  530  when the batteries need to be replaced. In some instances, the control module  542  may provide a beep or buzzer sound, or perhaps illuminate an LED in the CONNECT button  313  ( FIG. 11 ) in order to identify a location of the damper assembly  530  when pairing with remote sensors, in order to confirm that the damper assembly  530  is paired with the correct remote sensor, and that the one or more HVAC controller(s)  18  knows the particular location of the damper assembly  530 . In some cases, the sound generator  544  may be a speaker. In some instances, the sound generator  544  may instead be a piezoelectric device or other device configured to make audible sounds. 
       FIG. 22  is a schematic block diagram of an illustrative control module  550 . The control module  550  may be considered as being an example of the control module  134 , and may be configured to be operably coupled to a damper assembly  130 ,  131  that is placed within a duct  120  that supplies conditioned air through a register boot  122  to a register vent within a room. The illustrative control module  550  includes a control module housing  552  and a microphone  554  for providing an output signal that is representative of sounds sensed by the microphone  554 . A controller  556  is housed by the control module housing  552  and is operably coupled to the microphone  554 . In some cases, the controller  556  may be configured to control operation of the damper assembly. In some instances, the controller  556  may be configured to adjust operation of the damper assembly  130 ,  131  to reduce audible sounds sensed by the microphone  554  that are caused at least in part by the damper assembly  130 ,  131 . 
     In some instances, the control module  550  may include a memory  558  that is housed by the control module housing  552  and that is operably coupled to the controller  556 . The memory  558  may store a schedule indicating when the room is expected to be occupied, and wherein when the room is expected to be occupied, the controller  556  may be configured to control the damper assembly  130 ,  131  in a first mode that attempts to reduce audible sounds sensed by the microphone  554  caused at least in part by the damper assembly  130 ,  131 , and when the room is expected to be unoccupied, the controller  556  may be configured to control the damper assembly  130 ,  131  in a second mode that is different from the first mode. 
     The control module  550  may be configured to detect sounds that have an amplitude that is above an amplitude threshold and/or a frequency within a predetermined frequency range, and when detected, the controller  556  may be configured to make adjustments to the operation of the damper assembly  130 ,  131  to reduce the detected sounds. In some cases, the controller  556  may be further configured to operate the damper assembly  130 ,  131  in a first mode when the room is expected to be occupied and in a second mode when the room is expected to be unoccupied. 
       FIG. 23  is a schematic block diagram of a retrofit damper system  600  that is configured for installation in existing ductwork including a duct  120  supplying conditioned air through a register boot  122  to a register vent. The retrofit damper system includes a damper assembly  602  that is configured to be disposed within the duct  120 . The damper assembly  602  includes a damper blade  604  that is movable between a closed end position and an open end position. An electric damper motor  606  may be configured to drive the damper blade  604  to a desired position that is at or between the closed end position and the open end position. 
     A control module  608  is configured to be operably coupled to the damper assembly  602  and includes a control module housing  610  and a controller  612  that is disposed within the control module housing  610 . The control module housing  610  may be configured to be secured remote from the damper assembly  602  at a position within the register boot  122  and accessible with the register vent removed. The controller  612  may be configured to regulate operation of the electric damper motor  606 , and outputs a drive signal that causes the electric damper motor  606  to drive the damper blade  604  to a desired position. A power supply  614  including one or more batteries  616  is operably coupled to the controller  612 . In some cases, the power supply  614  includes a power supply housing  620  that is configured to be secured remote from the damper assembly  602  at a position within the register boot  122  and accessible with the register vent removed. 
     In some cases, in order to determine a relative position of the damper blade  604 , the controller  612  may be configured to create a plurality of interruptions in the drive signal while driving the damper blade  60  toward the desired position and to activate a sense circuit  618  (part of the control module  608 ) in order to sense a back EMF signal generated by the electric damper motor  606  during each of the plurality of interruptions in the drive signal. Each of the back EMF signals representative of the angular velocity of the electric damper motor  606  during the corresponding interruption. The controller  612  may be configured to estimate a current position of the damper blade  604  based at least in part on the back EMF signals sensed during the plurality of interruptions. In some cases, the estimate includes integrating the back EMF signals that are representative of velocity. By integrating velocity over time, an estimate of position can be obtained. The estimated position may be calibrated to a known position when the damper blade  604  is driven to an end stop position. In some cases, the controller  612  may periodically drive the damper blade  604  to an end stop position to re-calibrate the estimated damper position. 
     In some cases, the controller  612  may be configured to determine that the current position of the damper blade  604  corresponds to the closed end position (e.g. an end stop position) when the drive signal is driving the damper blade  604  toward the closed end position and one or more of the back EMF signals indicate that the angular velocity of the electric damper motor  606  is zero. When the controller  612  determines that the current position of the damper blade  604  corresponds to the closed end position, the controller  612  may reset the estimated current position to the closed end position. In some cases, the controller  612  may be configured to determine that the current position of the damper blade  604  corresponds to the open end position when the drive signal is driving the damper blade  604  toward the open end position and one or more of the back EMF signals indicate that the angular velocity of the electric damper motor  606  is zero. In some cases, when the controller  612  determines that the current position of the damper blade  604  corresponds to the open end position, the controller  612  may reset the estimated current position to the open end position. In some cases, the controller  612  may utilize an H-bridge switch in switching the drive signal between a first polarity for driving the electric damper motor  606  in a first rotational direction toward the closed end position, and a second opposing polarity for driving the electric damper motor  606  in a second opposite rotational direction toward the open end position. 
     In some cases, when the controller  612  determines that the current position of the damper blade corresponds to the closed end position, the controller  612  may reset the estimated current position to the closed end position. In some instances, the controller  612  is configured to determine that the current position of the damper blade corresponds to the open end position when the drive signal was driving the damper blade toward the open end position and the controller  612  determines that the damper has stopped moving based on at least one sensed back EMF signal. 
     In some instances, the controller  612  may be further configured to determine that the current position of the damper blade corresponds to the closed end position when the drive signal was driving the damper blade toward the closed end position and the controller  612  determines that the damper has stopped moving based on at least one sensed back EMF signal. When the controller  612  determines that the current position of the damper blade corresponds to the closed end position, the controller  612  may reset the estimated current position to the closed end position. In some cases, the controller  612  may be configured to determine that the current position of the damper blade corresponds to the open end position when the drive signal was driving the damper blade toward the open end position and the controller  612  determines that the damper has stopped moving based on at least one sensed back EMF signal. 
     The controller  612  may be configured to determine the estimated current position of the damper blade based at least in part on integrating a plurality of back EMF signals over time periods during which the damper blade is being driven towards desired positions and adding an integrated result multiplied by a velocity constant to the reset estimated position. In some cases, the controller  612  may be configured to receive a requested position and to drive the damper blade to the requested position by driving the damper blade towards the requested position while periodically estimating the position and stopping driving the damper blade when the absolute value of the estimated position minus the requested position is less than a limit. 
     In some cases, the controller  612  may be configured to take an estimated position reset action after a specified number of damper blade moves, and wherein the estimated position reset action includes moving to either the closed end position or the open end position, resetting the estimated position, zeroing a count of moves since a last estimated position reset action, then moving the damper blade to the requested position. The controller  612  may be configured to set a new value for the specified number of damper blade moves, where the new value is a count of moves that is present when the controller  612  determines it has reached a fully open or a fully closed position while attempting to move to a requested position. 
     The controller  612  may be configured to determine the velocity constant based on driving the damper blade over a full range of motion from a fully open position to fully closed position while integrating the back EMF signals over the driving time. In some cases, when the controller  612  determines that the current position of the damper blade corresponds to the open end position, the controller  612  may reset the estimated current position to the open end position. In some cases, the controller  612  may be configured to determine the estimated current position of the damper blade based at least in part on integrating a plurality of back EMF signals over time periods during which the damper blade is being driven towards desired positions and adding the integrated result multiplied by a velocity constant to the reset estimated position. In some cases, the controller  612  may be configured to receive a requested position and to drive the damper blade to the requested position by driving the damper blade towards the requested position while periodically estimating the position and stopping driving the damper blade when the absolute value of the estimated position minus the requested position is less than a limit. 
       FIG. 24  is a schematic block diagram of an illustrative damper system  640  that is configured for placement within an existing ductwork system that includes a duct that supplies conditioned air through a register boot to a register vent within a room of a building. The illustrative damper system  640  includes a damper  642  that is configured to be secured within the duct  120  of the existing ductwork system upstream of the register boot  122 . The damper  642  is rotatable between a closed end position in which air moving through the duct  120  is restricted from flowing past the damper  642  and through the register vent, and an open end position in which air moving through the duct  120  is less restricted from flowing past the damper  642  and through the register vent. The illustrative damper system  640  includes one or more sensors  644  as well as a control module  646  that is operably coupled to the damper  642  and to the one or more sensors  644 . While only a single sensor  644  is illustrated, it will be appreciated that two, three or more sensors  644  may be provided. The one or more sensors  644  may include, but are not limited to, one or more of an air quality sensor, a temperature sensor, a humidity sensor and/or an occupancy sensor. 
     The control module  646  may be configured to be secured within the register boot  122  downstream of the damper  642  and may include a controller  648  that is configured to control operation of the damper  642  and to report one or more sensed conditions to a building controller  650  that is located outside of the existing ductwork system when the one or more sensors  644  sense one or more conditions. In some cases, the control module  646  may also include a wireless transceiver  652  for reporting the one or more sensed conditions to the building controller  650 , and in some cases for receiving instructions from the building controller  650 . In some cases, at least some of the one or more sensors  644  are located within the control module  646 . In some instances, at least some of the one or more sensors  644  are remote from the damper system  640  (e.g. in the living space), and wirelessly communicate with the controller  648  via the wireless transceiver  652 . In some cases, the damper system  640  may include an air filter  654  that may be disposed downstream of the damper  642 . 
     In some instances, the building controller  650  may be an HVAC controller for controlling an HVAC system of the building, and may control operation of the HVAC system of the building. In some cases, the controller  648  of the control module  646  may be configured to transmit to the HVAC controller a request for a change in operation of the HVAC system based at least in part upon information received by the controller  648  from the one or more sensors  644 . A change in operation of the HVAC system may, for example, include one or more of a request to activate one or more of a heater, an air conditioner, a fan, a humidifier, and a ventilator of the HVAC system. 
     In some cases, if the one or more sensors  644  includes an air quality sensor, the controller  648  may be configured to report an air quality problem to the building controller  650  when the air quality sensor senses that the sensed air quality has crossed an air quality threshold. In some instances, the one or more sensors  644  may instead be in communication directly with the building controller  650 , and the building controller  650  may determine that the sensed air quality has crossed an air quality threshold. If the one or more sensors  644  includes a humidity sensor, the controller  648  may be configured to report a humidity condition to the building controller  650  when the humidity sensor senses that the sensed humidity has crossed a humidity threshold. In some instances, the one or more sensors  644  may instead be in communication directly with the building controller  650 , and the building controller  650  may determine that the humidity has crossed a humidity threshold. 
     If the one or more sensors  644  includes an occupancy sensor, the controller  648  may be configured to report an occupied condition to the building controller  650  when the occupancy sensor senses occupancy. If the one or more sensors  644  includes an air flow sensor, the controller  648  may be configured to report an air flow condition to the building controller  650  when the air flow sensor senses that the sensed air flow has crossed an air flow threshold. If the one or more sensors  644  includes a temperature sensor, the controller  648  may be configured to report a temperature condition to the building controller  650  when the temperature sensor senses that the sensed temperature has crossed a temperature threshold. In some cases, the building controller  650  may activate the appropriate building system to address the condition(s) indicated by the controller  648 . In some cases, as noted, the one or more sensors  644  may instead report directly to the building controller  650 , which may then decide to take appropriate action. 
     When the one or more sensors  644  includes an occupancy sensor, the controller  648  of the control module  646  may be configured to operate the damper  642  in accordance with a first control algorithm when the room is indicated to be occupied and may operate the damper  642  in accordance with a second control algorithm when the room is not indicated as being occupied. For example, when the room is occupied, the damper  642  may be controlled such that the controlled parameter(s) (e.g. temperature) are controlled within a tighter range (e.g. smaller dead band) than when the room is un-occupied. The dead band refers to an allowable temperature swing between an actual temperature and a temperature setpoint. When the room is occupied, the temperature is not allowed to vary as much, for example. 
     In some cases, the damper  642  includes a damper frame  660  and a damper blade  662  that is rotatably securable relative to the damper frame  660  and is rotatable between a closed end position in which air moving through the existing ductwork is restricted from flowing past the damper blade  662  and through the register vent, and an open end position in which air moving through the existing ductwork is less restricted from flowing past the damper blade  662  and through the register vent. A damper motor  664  is operably coupled to the damper frame  660  and the damper blade  662 , and is configured to rotate the damper blade  662  relative to the damper frame  660  between the closed end position and the open end position. 
       FIG. 25  is a schematic block diagram illustrating a room comfort assembly  668  that is configured for placement within an existing ductwork system that includes a duct that supplies conditioned air through a register boot to a register vent within a room. The room comfort assembly  668  includes a damper  670  that is configured to be positioned upstream of the register vent and that is rotatable between a closed end position in which air moving through a duct  120  is restricted from flowing past the damper  670  and through the register vent, and an open end position in which air moving through the duct  120  is less restricted from flowing past the damper  670  and through the register vent. A replaceable fragrance cartridge  672  is configured to be positioned upstream of the register vent for selectively releasing a fragrance. A controller  674  is configured to be positioned upstream of the register vent and operatively coupled to the damper  670  and the fragrance cartridge  672 . The controller  674  may be configured to control operation of the damper  670  and to selectively activate the release of fragrance from the fragrance cartridge  672 . 
       FIG. 26  is a perspective view of the power module  136 . The illustrative power module  136  has a housing  680  and a hinged top  682 .  FIG. 27  shows the power module  136  with the hinged top  682  removed, and  FIG. 28  shows the hinged top  682 . The hinged top  682  may include first hinge sections  684  that hingedly interact with second hinge sections  686  that are disposed on the housing  680 . Together, the first hinge sections  684  and the second hinge sections  686  cooperate to hingedly couple the hinged top  682  to the housing  680 . The hinged top  682  also includes a latch  688  that releasably secures the hinged top  682  to the housing  680 . With the hinged top  682  removed, as shown in  FIG. 27 , it can be seen that the illustrative power module  136  accommodates one or more batteries  690  (two are shown) within the housing  680 , as well as the necessary electrical couplings  692 . By mounting the power module  136  at a location accessible by a homeowner, such as within the register boot  122 , it will be appreciated that a homeowner will be able to easily access the power module  136  in order to change batteries when necessary. In some cases, the power module  136  may be magnetically coupled to the register boot  122 . Alternatively, the power module  136  may be screwed or otherwise secured to the register boot  122 . 
       FIG. 29  is a side view of another illustrative damper assembly  700  shown deployed within a clear duct  120   a , and  FIG. 30  is a perspective view of the illustrative damper assembly  700 . In  FIG. 30 , the flexible polymeric portion of the single blade has been removed to better illustrate other features and elements of the damper assembly  700 . The illustrative damper assembly  700  includes a damper  702  that is coupled with an elongated deployment member  704  that may, for example, be similar to the elongated deployment member  132  shown in previous Figures. In some cases, the elongated deployment member  704  is configured to facilitate placement of the damper body  706  in a duct of an existing ductwork system of a building from an installation location outside of the duct, such as within or even exterior to a register boot. In some cases, the elongated deployment member  704  may be configured to be secured to the register boot, and to extend upstream therefrom in order to help hold the damper assembly  702  in position within the duct  120   a.    
     The damper assembly  702  includes a damper body  706  and a damper blade  708  that is pivotably secured relative to the damper body  706 . The damper blade  708  includes a resilient seal  710  that extends radially outwardly from the damper blade  708 . The damper blade  708  is pivotably movable between a first position in which air flow is restricted from flowing past the damper blade  708  (as shown in  FIG. 29 ) and a second position in which air flow is less restricted from flowing past the damper blade  708 . 
     A drive motor  712  is secured relative to the damper body  706 , and in some cases may be disposed within the damper body  706 . The drive motor  712  may be configured to move the damper blade  708  between the first position and the second position. In some cases, the drive motor  712  has a drive motor axis of rotation L 4 , and the damper blade  708  has a pivot axis L 5  along which the damper blade  708  pivots, and the pivot axis L 5  is parallel to the drive motor axis of rotation L 4 . In some cases, the pivot axis L 5  is collinear with the drive motor axis of rotation L 4 , but this is not required in all cases. 
     In some cases, the damper assembly  702  includes a first pair of spring-loaded standoffs  720  that extend radially outwardly from the damper body  706 . Each of the first pair of spring-loaded standoffs  720  extend orthogonally to the elongated deployment member  704 . In some instances, the damper assembly  702  includes a second pair of spring-loaded standoffs  722  that extend radially outwardly from the damper body  706 . Each of the second pair of spring-loaded standoffs  722  may extend orthogonally to the elongated deployment member  704  as well as being orthogonal to the first pair of spring-loaded standoffs  720 . It will be appreciated that each of the spring-loaded standoffs  720  and  722  may be biased into a position (shown in  FIG. 30 ) in which they extend straight out from the damper body  706 , and may deflect (shown in  FIG. 29 ) as they interact with an inner surface of the duct  120   a . The spring-loaded standoffs  720 ,  722  may deflect further while the damper assembly  702  is being advanced through the duct work, and may attempt to regain their straight configuration once the damper assembly  702  is in position, thereby anchoring the damper assembly  702  in place, roughly centered within the duct  120   a.    
       FIG. 31  a side view of another illustrative damper assembly  750  shown deployed within a clear duct  120   a .  FIG. 32  is a perspective view of the damper assembly  750  in which the flexible polymeric portions of damper blades have been removed to better illustrate other features and elements of the damper assembly  750 .  FIG. 33  is a perspective view of a portion of the damper assembly  750 . The illustrative damper assembly  750  includes a damper assembly  752  that is coupled to an elongated deployment member  754 . The damper assembly  750  is configured for placement within an existing ductwork system that includes a duct that supplies conditioned air through a register boot to a register vent within a room of a building. The damper assembly  752  includes a damper body  756  and a threaded rod  758  that extends in an upstream direction from the damper body  756 . The threaded rod  758  is operably coupled to a drive motor  760  that is secured to the damper body  756 . In some cases, the drive motor  760  is disposed within the damper body  756 . The threaded rod  758  is configured to rotate in response to the drive motor  760  being actuated. A nut  762  is threadedly engaged with the threaded rod  758 . 
     The damper assembly  752  includes a first damper blade segment  764  that is pivotably secured to the damper body  756  and extends upstream from the damper body  756 . The first damper blade segment  764  includes a first linking segment  766  that extends between the first damper blade segment  764  and the nut  762 . The damper assembly  752  includes a second damper blade segment  768  that is pivotably secured to the damper body  756  and extends upstream from the damper body  756 . The second damper blade segment  768  includes a second linking segment  770  that extends between the second damper blade segment  768  and the nut  762 . It will be appreciated that the first linking segment  766  and the second linking segment  770  constrain the nut  762  against rotation such that rotation of the threaded rod  758  causes the nut  762  to translate along the threaded rod  758 , and translation of the nut  762  in a first direction indicated by an arrow  780  causes the first damper blade segment  764  and the second damper blade segment  768  to pivot closer together while translation of the nut  762  in a second direction indicated by an arrow  782  causes the first damper blade segment  764  and the second damper blade segment  768  to pivot farther apart. It will be appreciated that the first damper blade segment  764  and the second damper blade segment  768  move in unison, either both moving away from each other or both moving towards each other. A resilient seal  790  extends radially outwardly from the first damper blade segment  764  and the second damper blade segment  768 . The resilient seal  790  has a shape that facilitates the resilient seal  790  sealing against an interior of the duct  120   a  when the first damper blade segment  764  and the second damper blade segment  768  move away from each other sufficiently far to engage the inner surface of the duct. 
     In some cases, and as best shown in  FIG. 32 , the first damper blade segment  764  includes a first side  800  and a second side  802  that is parallel to the first side  800 . A curved side  804  extends between the first side  800  and the second side  802 . The first damper blade segment  764  may include a first cutout portion  806  that is configured to enable the first linking segment  766  to move at least partially into the first cutout portion  806  when the first damper blade segment  764  moves towards the threaded rod  758  and the nut  762 . The first linking segment  766  may be considered as being complementary to the first cutout portion  806 . 
     In some cases, the second damper blade segment  768  includes a first side  808  and a second side  810  that is parallel to the first side  808 . A curved side  812  extends between the first side  808  and the second side  810 . The second damper blade segment  768  may include a second cutout portion  814  that is configured to enable the second linking segment  770  to move at least partially into the second cutout portion  814  when the second damper blade segment  768  moves towards the threaded rod  758  and the nut  762 . The second linking segment  770  may be considered as being complementary to the second cutout portion  814 . 
     In some cases, and as best shown in  FIG. 33 , the drive motor  760  has a drive motor axis of rotation L 6  and the damper blade (collectively the first damper blade segment  764  and the second damper blade segment  768 ) has a pivot axis L 7  along which the damper blade pivots, and the pivot axis L 7  is perpendicular to the drive motor axis of rotation L 6 . Put another way, the first damper blade segment  764  and the second damper blade segment  768  are each pivotally secured at one end thereof to the damper body  756  and pivot relative to a plane extending through the damper body  756  and passing between the first damper blade segment  764  and the second damper blade segment  768 . 
     Those skilled in the art will recognize that the present disclosure may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present disclosure as described in the appended claims.