Patent Publication Number: US-11656000-B2

Title: Burner control system

Description:
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/886,773 (filed Aug. 14, 2019), which is entitled, “BURNER CONTROL SYSTEM” and incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The disclosure relates to water heating systems. 
     BACKGROUND 
     Tank-type water heating systems which incorporate gas combustion as a heat source typically utilize a pilot flame issuing from a pilot burner to initiate combustion of a main gas flow. Combustion of the main gas flow initiates a flame at a main burner. The main burner flame typically heats a volume of water. A temperature sensing device in thermal communication with the volume of water may provide a temperature to a control system to serve as an indication of when pilot flame and main burner flame may be desired. The control system may initiate operations within the water heater system to initiate the pilot flame and the main burner flame by, for example, energizing valve actuators in order to establish the necessary gas flows to one or more dormant burners. 
     SUMMARY 
     In general, the water heater control system disclosed provides for energy usage of components in a water heater system. For example, the water heater system includes a rechargeable and non-rechargeable power source. In one or more examples, a controller such as a microcontroller of the water heater system is configured to receive power from the non-rechargeable power source and does not receive power from the rechargeable power source. Various other components of the water heater system are configured to receive power from the rechargeable power source. 
     By separating out the power sources for the microcontroller and the other components, the microcontroller may be guaranteed to receive power on demand with a non-rechargeable power source that provides power for the lifetime of the water heater system. With the non-rechargeable power source, the other components of the water heater system have a reliable power source that can be recharged as needed. Since the other components (e.g., other than microprocessor) do not receive power from the non-rechargeable power source, there is sufficient power for the microcontroller, allowing for uninterrupted operation of the microcontroller, while not draining the non-rechargeable power source. The rechargeable power source can provide power to the other components as needed, and can be recharged. In this way, the disclosure describes for a water heater system with robust power delivery mechanism to ensure that power is available as needed. 
     In an example, the disclosure provides a water heater comprising a power source that is non-rechargeable, a controller configured to receive power from the power source, an energy storage system comprising a rechargeable power supply and configured to provide power to one or more components of the water heater, wherein the water heater is configured to prevent the controller from receiving power from the rechargeable power supply, and a thermoelectric device configured to provide power to recharge the rechargeable power supply, wherein the thermoelectric device is configured to generate power in response to a pilot flame in proximity to the thermoelectric device. 
     In an example, the disclosure provides a water heater system comprising a first valve operator, wherein the first valve operator initiates a first gas flow when energized, an energy storage system coupled to energize the first valve operator, a power source coupled to recharge the energy storage system, a pilot ignition circuit configured to cause a pilot spark ignitor to generate a pilot flame using the first gas flow, a second valve operator, wherein the second valve operator initiates a second gas flow when energized, wherein the second gas flow is greater than the first gas flow, and wherein the second valve operator cannot be energized from the energy storage system, and a thermoelectric device that converts thermal energy from the pilot flame into electrical energy, the thermoelectric device coupled to provide a first portion of the electrical energy to energize the second valve operator and the thermoelectric device coupled to provide a second portion of the electrical energy to the energy storage system. 
     In an example, the disclosure provides a method of generating a main burner flame comprising initiating a first gas flow using a first valve operator configured to initiate the first gas flow when energized by energizing the first valve operator using an energy storage system coupled to the first valve operator, thereby initiating the first gas flow, prompting a pilot ignition circuit to cause a pilot spark ignitor in thermal communication with the first gas flow to generate ignition energy, thereby generating a pilot flame, allowing a thermoelectric device in thermal communication with the pilot flame to convert thermal energy from the pilot flame to electrical energy, initiating a second gas flow using a second valve operator configured to initiate the second gas flow when energized by energizing the second valve operator using a first portion of the electrical energy, thereby initiating the second gas flow, providing a second portion of the electrical energy to the energy storage system, and porting the second gas flow to a burner configured to establish thermal communication between the second gas flow and the pilot flame, thereby generating the main burner flame. 
     The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a diagram of a pilot light and appliance burner integration in a water heater system. 
         FIG.  2 A  is an example pilot valve and main valve apparatus with a pilot servo valve and main servo valve in a closed position. 
         FIG.  2 B  is the example pilot valve and main valve apparatus with the pilot servo valve in an open position and the main servo valve in a closed position. 
         FIG.  2 C  is an example pilot valve and main valve apparatus with the pilot servo valve and the main servo valve in the open position. 
         FIG.  3    is an example of a control system for an intermittent pilot water heater. 
         FIG.  4    is a second example of a control system for an intermittent pilot water heater. 
         FIG.  5    is a flowchart illustrating an example method for establishing a main burner flame. 
     
    
    
     DETAILED DESCRIPTION 
     The water heater control system includes an energy storage system and may operate in the absence of an external power supply, such as a line voltage provided by existing energy infrastructure to a residence or some other structure. The energy storage system may be electrically connected to a pilot valve operator which controls whether there is a pilot gas flow to a pilot gas burner. The energy storage system may comprise rechargeable energy storage system, non-rechargeable energy storage system, or both. For example, energization of the pilot valve operator may cause operation of a servo valve which initiates the pilot gas flow. The energy storage system may additionally be electrically connected to an ignition circuit causing a pilot spark ignitor to generate thermal energy. The pilot spark ignitor may be in close proximity to and/or in thermal communication with the pilot gas flow, initiating a pilot flame at the pilot burner. 
     A thermoelectric device is in thermal communication with the pilot flame. The thermoelectric device (e.g., a thermopile) converts some portion of the thermal energy received from the pilot flame into electrical energy. In accordance with one or more examples described in this disclosure, the thermoelectric device is electrically connected to a main valve operator, which controls whether there is a main gas flow to a main burner. For example, energization of the main valve operator may cause operation of a servo valve which initiates the main gas flow. The thermoelectric device may also provide power to the energy storage system and the pilot valve operator when the thermoelectric device is generating electrical power. 
     The main valve operator may be electrically isolated from the energy storage system by, for example, a unidirectional power convertor or some other component. In some examples, the main valve operator has a high electrical resistance such that electrical energy provided by the energy storage system is insufficient to operate the main valve operator. This prevents the energy storage system from providing sufficient power to operate the main valve operator. The main valve operator which initiates main gas flow may only be sufficiently energized by the thermoelectric device, which only generates sufficient electrical energy once the pilot flame has been established. This safeguards against initiation of a main gas flow prior to establishment of an active pilot flame and avoids discharges of uncombusted fuel into enclosed spaces or other environments. 
     The water heater control system may include a power source, such as one or more batteries and/or capacitors. The power source may be electrically connected to the energy storage system, in order to recharge the energy storage system when necessary. In general, the thermoelectric device generates the power that recharges the energy storage system, but in some instances, power from the power source may be needed to recharge the energy storage system to cause the pilot flame to ignite. The power source may be pre-charged and intended to last all or some significant portion of the life of the associated water heater. The power source may be replaceable and may be rechargeable. 
     The water heater control system may include a controller such as a microcontroller configured to establish electrical communication between the thermoelectric device and the energy storage system, the pilot valve operator, and the main valve operator. The microcontroller may be configured to create and/or initiate a call for main burner operation, and in response, establish the electrical communication. The microcontroller may also be configured to check an available voltage of the energy storage system against a setpoint. Based on the available voltage, the microcontroller may establish electrical connection between the power source and the energy storage system, in order to maintain the stored energy system in a condition necessary to initiate the pilot gas flow when called for. The microcontroller may be powered by the thermoelectric device when the thermoelectric device is generating electrical power. The microcontroller may also be powered by the power source. In some examples, the microcontroller being powered by the power source allows the microcontroller to periodically conduct checks throughout the system. This may be particularly advantageous when the water heater control system operates in the absence of an external power supply such as a line voltage provided by a separate infrastructure. 
       FIG.  1    provides an example water heating system comprising pilot burner  41  and main burner  42  integrated in a water heater system  70 . Fuel line  46  is in fluid communication with a main valve  44 , which controls fuel flow to a main burner  42 . A flue  50  may be an exhaust for main burner  42  in system  70 . A pilot valve (not shown) may control fuel flow to a pilot burner  41  through fuel line  58 . The pilot valve may be substantially in series or in some other arrangement with main valve  44 , and fuel to pilot burner  41  may come from fuel line  46  or some other source. There may be a pilot spark ignitor  56 , for igniting a pilot gas flow discharging from pilot burner  54 . 
     There may be a thermoelectric device  66  such as a thermopile connected by an electrical line  52  to control system  71 . There may be a pilot spark ignitor  56  for igniting a pilot gas flow discharging from pilot burner  41 . Pilot spark ignitor  56  may be connected via electrical line  60  to control system  71 . Thermoelectric device  66  may be in thermal communication with pilot flame generated at pilot burner  41 , and may convert some portion of a heat flux emitted by the pilot flame into electrical energy. A temperature sensing device  62  may be connected to control system  71  and situated in a water tank  64 , or otherwise be configured to be in thermal communication with a volume of water in water tank  64 . Control system  71  may incorporate a controller such as a microcontroller configured to establish electrical or data communication with one or more of main valve  44 , the pilot valve, and other components. 
     Control system  71  may include a pilot valve operator configured to actuate the pilot valve of system  70 , and may include a main valve operator configured to actuate main valve  44 . Control system  71  may also establish an electrical connection between thermoelectric device  66  and the main valve operator, such that the main valve operator can be powered by thermoelectric device  66 . Control system  71  may also include an energy storage system in electrical connection with the pilot valve operator. 
     In an intermittent pilot light system, when main burner  48  operation is called for, an operating sequence in system  70  might initially actuate the pilot valve and establish a pilot flame at pilot burner  41  prior to commencing main valve  44  operations. For example, control system  71  might initially actuate the pilot valve and pilot spark ignitor  56  using an energy storage system in order to establish the pilot flame at pilot burner  41 . Subsequently, once the pilot flame is established, the operating sequence might actuate main valve  44  using power delivered by thermoelectric device  66 . In this manner, main fuel flow to main burner  48  may be established and the pilot flame may generate combustion of the main fuel flow. A sequence ensuring that the pilot flame is established prior to initiating main fuel flow to the burner avoids situations leading to discharges of uncombusted main fuel into surrounding environments. 
       FIGS.  2 A- 2 C  illustrates an example pilot valve and main valve configuration. At  FIG.  2 A , diaphragm  124  is illustrated in a closed position isolating an inlet  122 , an intermediate pressure chamber  130 , and a pilot outlet  132 . Inlet  122  may be in fluid communication with a fuel supply and pilot outlet  132  may be in fluid communication with a pilot burner. Diaphragm  124  in the position illustrated is isolating the fuel supply and the pilot burner, at least at location  158 . Diaphragm  124  is acted on by spring member  126 , and fluid pressures in inlet  122  and chamber  128  are substantially equal, so that diaphragm  124  is maintained in the closed position. Servo valve  134  is maintaining disc  136  in a position isolating conduit  138  and intermediate pressure chamber  130  (intermediate pressure chamber  130  comprises and extends across  130   a ,  130   b , and  130   c ), maintaining the fluid pressures in inlet  122  and chamber  128  substantially equal. Additionally, fluid pressures in inlet  122  and chamber  128  are greater than a pressure at intermediate pressure chamber  130  and pilot outlet  132 . 
     Valve body  120  also has diaphragm  142 , and servo valve  152  having disc  154 . Diaphragm  142  is in a closed position isolating intermediate pressure chamber  130  (comprising  130   a ,  130   b , and  130   c ) and outlet  148  at least at position  160  (outlet  148  comprises and extends across  148   a ,  148   b , and  148   c ). Outlet  148  may be in fluid communication with a main burner. Diaphragm  142  is acted on by spring member  144 , and diaphragm  124  is maintained in the closed position at least by spring member  144 . The pressure of chamber  146  is equalized with outlet  148  through conduit  162 . 
     A pilot valve operator may be configured to cause servo valve  134  to reposition disc  136 . In an example, control system  71  may be configured to energize the pilot valve operator using a stored energy system. For example,  FIG.  2 B  illustrates valve body  120  with servo valve  134  having positioned disc  136  to allow fluid communication between chamber  128  and intermediate pressure chamber  130 . This provides at least some venting of the pressure in chamber  128  through first supply orifice  140  and reduces the pressure of chamber  128 . This allows the pressure of inlet  122  to position diaphragm  124  into the position shown, where fluid communication between inlet  122  and pilot outlet  132  may occur at least at location  158 . This allows fluid communication between inlet  122  and pilot outlet  132 , and may allow a fuel supply to proceed from inlet  122  to the pilot burner. Additionally, with  152  closed, the pressure of chamber  146  is substantially equalized with intermediate pressure chamber  130  through conduit  162 , and diaphragm  142  remains in the closed position. 
     With fuel supplied to the pilot burner, such as pilot burner  41 , an ignitor such as ignitor  56  may establish a pilot flame at pilot burner  41  ( FIG.  1   ). Thermoelectric device  66  in thermal communication with the pilot flame may convert some portion of the heat flux emitted by the pilot flame into electrical energy. 
     A main valve operator may be configured to cause servo valve  152  to reposition disc  154 . In an example, control system  71  may be configured to energize the main valve operator using electrical power from a thermoelectric device such as thermoelectric device  66 . For example,  FIG.  2 C  illustrates valve body  120  with servo valve  152  having positioned disc  154  to allow fluid communication between chamber  146  and outlet  148  though conduit  150 . This allows at least some venting of the pressure in chamber  146  through second supply orifice  157  and reduces the pressure of chamber  146 . The venting of chamber  146  through conduit  150  allows the pressure of intermediate pressure chamber  130  to position diaphragm  142  into the position shown, where fluid communication between intermediate pressure chamber  130  and outlet  148  (comprising  148   a ,  148   b , and  148   c ) may occur at least at location  160 . With servo valve  134  and servo valve  152  both positioned as shown at  FIG.  2 C , this allows fluid communication between inlet  122  and outlet  148 , and may allow a fuel supply to proceed from inlet  122  to a main burner, such as main burner  42  ( FIG.  1   ). 
     With fuel supplied to the main burner and the pilot flame established, a main flame may be generated at the main burner. In examples where control system  71  uses a stored energy system to energize the pilot valve, and utilizes electrical energy generated through thermal communication with an established pilot flame to energize a main valve, control system  71  provides a safeguard against discharges of uncombusted fuel into enclosed spaces or other environments. This may be particularly advantageous in water heater systems such as water heater system  70 , where a main gas flow to main burner  41  is intended to be significantly greater than the pilot gas flow provided to pilot burner  41 . 
       FIG.  3    illustrates an example water heater control system  10  which may be configured to provide for generation of a main burner flame in a manner that guards against initiation of a main gas flow prior to establishment of an active pilot flame. System  10  may provide advantage in water heater systems such as that depicted at  FIG.  1   , where main gas flows intended to sustain main burner operations are typically much greater than the smaller pilot gas flows which generate the pilot flame. System  10  may be utilized to guard against potentially large discharges of uncombusted fuel into enclosed spaces or other environments. 
     System  10  is an electric circuit configured to receive power from a thermoelectric device  16 . Thermoelectric device  16  is a component configured to convert thermal energy into electrical power, such as a thermopile. System  10  additionally comprises pilot valve operator  12  and main valve operator  14 , as well as convertor  18 . As illustrated, thermoelectric device  16  may provide power to main valve operator  14  through electrical line  34 , and to convertor  18  through electrical connection  36 . Convertor  18  may forward the generated power through electrical line  39  to energy storage system  20  through electrical connection  40 , and to pilot valve operator  12  through electrical connection  38 . Energy storage system  20  may also provide power to pilot valve operator  12  through electrical connection  40  and electrical connection  38 . Energy storage system  20  may thus provide the capability to store some portion of the electrical power generated by thermoelectric device  16 , and also provides for powering of pilot valve operator  12  when thermoelectric device  16  is not generating. For example, thermoelectric device  16  may be configured to be in thermal communication with a heat source intended to operate intermittently, such as an intermittent pilot flame in a water heater, and power from thermoelectric device  16  to pilot valve operator  12  may not always be available. In such cases, energy storage system  20  may provide power to pilot valve operator  12 , among other components. Energy storage system  20  may power pilot valve operator  12  using rechargeable and/or non-rechargeable storage components. Energy storage system  20  may also power an ignition circuit  24  using a rechargeable and/or non-rechargeable storage components via electrical connection  40 , electrical line  39 , and electrical connection  51 . 
     System  10  further comprises a power source  31 , such as a battery or capacitor. The power source may be a non-rechargeable battery or pre-charged capacitor intended to last all or some significant portion of the life of the associated water heater. Power source  31  may be replaceable and may be rechargeable. Power source  31  is configured to provide recharging power to energy storage system  20  through electrical connection  33 . System  10  may further comprise a controller such as microcontroller  22  configured to receive electrical power from power source  31 , or thermoelectric device  16  via converter  45 . System  10  may further comprise one or more electronic devices, such as first electronic device  26  between electrical line  39  and pilot valve operator  12 , second electronic device  28  between electrical line  34  and main valve operator  14 , third electronic device  30  between power source  31  and energy storage system  20 , fourth electronic device  47  between power source  31  and energy storage system  20 , and fifth electronic device  49  between electrical line  39  and ignition circuit  24 . Microcontroller  22  be configured to control first electronic device  26 , second electronic device  28 , third electronic device  30 , fourth electronic device  49 , and fifth electronic device  49  to carry out various operations of system  10 , as will be discussed. System  10  may be contained either wholly or in part within a control module casing  11 . Although not illustrated in  FIG.  1   , microcontroller  22  may be electrically connected to the various electronic devices to control the flow of current through first electronic device  26 , second electronic device  28 , third electronic device  30 , fourth electronic device  49 , and fifth electronic device  49 . 
     System  10  is configured to limit power flow from node  35  to energy storage system  20  to a single direction, so that while energy storage system  20  may receive power from thermoelectric device  16  via node  35  and converter  18 , power flow cannot occur from energy storage system  20  to any components where node  35  is in the electrical path, such as main valve operator  14 . In some examples, convertor  18  is a unidirectional device such as a unidirectional DC-DC-convertor which limits power flow from node  35  through electrical line  39  to the single direction. The unidirectional flow of power from node  35  results in an arrangement whereby, when thermoelectric device  16  is receiving thermal energy and generating power, thermoelectric device  16  may deliver power to main valve operator  14  and converter  18 , and converter  18  may deliver power to pilot valve operator  12  and energy storage system  20 . However, when thermoelectric device  16  is not generating electrical power, energy storage system  20  may deliver power to pilot valve operator  12 , but not to main valve operator  14 . System  10  is thereby configured such that main valve operator  14  can only receive power when thermoelectric device  16  is generating power, whereas pilot valve operator  12  may receive power from thermoelectric device  16  (when thermoelectric device  16  is generating) or energy storage system  20  (when thermoelectric device  16  is not generating). System  10  is additionally configured so that energy storage system  20  may not provide power to microcontroller  22 . 
     Using a unidirectional DC-DC convertor for convertor  18  is one example way to ensure that energy storage system  20  does not deliver power to activate main valve operator  14 . However, the example techniques are not so limited and other techniques to ensure that energy storage system  20  does not deliver sufficient power may be possible. For example, components such as diodes, switches, etc. At  36  or  39  may be used to ensure that energy storage system  20  does not provide sufficient power to activate main valve operator  14 . Also, the above approaches provide example manners in which to ensure that main valve operator  14  receives sufficient power only from thermoelectric device  16 . However, these examples are not intended to be exhaustive, and system  10  may utilize any configuration which allows thermoelectric device  16  to provide sufficient activation power to main valve operator  14  while preventing energy storage system  20  from providing the sufficient activation power. 
     In some examples, during an initial startup, energy storage system  20  may not store any power. In this case, power source  31  may output power to energy storage system  20  to charge energy storage system  20  to such a level that energy storage system  20  can deliver sufficient power to ignition circuit  24  to cause ignition circuitry  24  to deliver power to ignitor  32  to start the pilot flame. In response to the pilot flame, thermoelectric device  16  may generate power that recharges energy storage system  20 . 
       FIG.  4    illustrates another example water heater control system  400  which may be configured to provide for generation of a main burner flame in a manner that guards against initiation of a main gas flow prior to establishment of an active pilot flame. System  400  may provide advantage in water heater systems such as that depicted at FIG.  1  and may be utilized to guard against potentially large discharges of uncombusted fuel into enclosed spaces or other environments. 
     System  400  is configured to receive power from thermoelectric device  16 , and comprises pilot valve operator  12  and main valve operator  414 . System  400  also comprises convertor  418 . Thermoelectric device  16  may provide power to electrical line  436  and energy storage system  20  through electrical connection  40  and pilot valve operator  12  through electrical connection  38 . Thermoelectric device  16  may provide power to convertor  418  through electrical line  436  and electrical connection  439 . Convertor  418  may forward the generated power through electrical line  434  to main valve operator  414 . Energy storage system  20  may also provide power to pilot valve operator  12  through electrical connection  40  and electrical connection  38 . Energy storage system  20  may also power an ignition circuit  24 . System  400  further comprises power source  31  configured to provide recharging power to energy storage system  20  through electrical connection  33 . System  400  may further comprise a controller such as microcontroller  22  configured to receive electrical power from power source  31  via electrical line  37  and from thermoelectric device  16  via converter  445 . Microcontroller  22  may be configured to control first electronic device  26 , second electronic device  28 , third electronic device  30 , fourth electronic device  47 , and fifth electronic device  49  to carry out various operations of system  400 , as will be discussed. System  400  may be contained either wholly or in part within control module casing  411 . 
     In system  400 , main valve operator  414  is configured to have a high electrical resistance such that main valve operator  414  cannot actuate a valve (such as servo valve  152 ) when supplied with a voltage typical of the output voltage produced by thermoelectric device  16 . The electrical resistance of main valve  414  is such that main valve  414  may only be sufficiently energized to actuate the necessary valve when thermoelectric device  16  is generating a voltage (i.e., the pilot flame is lit) and converter  418  is stepping up the voltage from the generated level to a level sufficient to cause main valve operator  44  to actuate. This provides an arrangement whereby, when thermoelectric device  16  is receiving thermal energy and generating power, thermoelectric device  16  may deliver power to energy storage system  20 , pilot valve operator  12 , and converter  418 , and converter  418  may deliver a stepped up voltage to main valve operator  414 . However, when thermoelectric device  16  is not generating electrical power, energy storage system  20  may deliver power and cause operation of pilot valve operator  12 , but cannot provide sufficient power to cause converter  418  to deliver power sufficient to operate main valve operator  14 . System  400  is thereby configured such that main valve operator  414  can only operate when thermoelectric device  16  is generating power, whereas pilot valve operator  12  may receive power from thermoelectric device  16  (when thermoelectric device  16  is generating) or energy storage system  20  (when thermoelectric device  16  is not generating). System  400  may be additionally configured such that, when thermoelectric device  16  is not generating electrical power, energy storage system  20  cannot provide sufficient power to cause converter  445  to deliver power to microcontroller  22 . 
     In an example, thermoelectric device  16  generates a first amount of electrical energy and operation of main valve operator  414  requires a second amount of electrical energy, and the second amount of energy is greater than the first amount of energy. Thermoelectric device  16  may generate the first amount of electrical energy when thermoelectric device  16  is in thermal communication with a pilot flame from a pilot burner, such as pilot burner  41  ( FIG.  1   ). Thermoelectric device  16  may provide the first amount of electrical energy to a converter, and the converter may receive the first amount of electrical energy and provide the second amount of electrical energy to main valve operator  414 . Main valve operator  414  may comprise an element or coil configured to provide a resistance such that the first amount of electrical energy is insufficient to cause operation of main valve operator  414 . 
     System  10  and system  400  may provide advantage in an apparatus where a first gas flow sustains a first flame generating a heat flux, and some portion of the heat flux impinges on some portion of a second gas flow in order to generate a second flame. In such devices, it may be advantageous to ensure the first flame is operating before commencing the second gas flow, in order to avoid discharges of uncombusted fuel into enclosed spaces or other environments, or for other reasons. This may be particularly advantageous when the second gas flow is significantly larger than the first gas flow (e.g., the second gas flow has a greater mass flow rate than the first gas flow). For example, it may be advantageous in water heater systems where a smaller pilot gas flow sustains a pilot flame at a pilot burner, and the pilot flame is in thermal communication with a larger main gas flow to generate a flame at a main burner. In  FIGS.  3  and  4   , main valve operator  14  only opens to allow gas flow to the main burner when electrical power (e.g., voltage and current) are generated from thermoelectric device  16 . Thermoelectric device  16  may only generate the electrical power in response to the pilot flame. Hence, main valve operator  14  may not open unless the pilot flame is available. For example, when the pilot flame is dormant, thermoelectric device  16  is does not generate sufficient (or any) electrical power. Since there is little to no electric power from thermoelectric device  16 , main valve operator  14  remains in a closed state and gas flow cannot be provided to the main burner. 
     Control system  10  and control system  400  may be utilized in an intermittent pilot light system to effectively ensure that a pilot flame is established prior to initiating main fuel flow to a main burner. Pilot valve operator  12  may be configured to actuate a pilot valve such as the pilot valve of system  70  ( FIG.  1   ), and main valve operator  14  may be configured to actuate a main valve such as main valve  44  ( FIG.  1   ). Thermoelectric device  66  may be configured to be in thermal communication with a pilot flame sustained by a pilot burner  41 , such that at least some portion of a heat flux generated by the pilot flame of pilot burner  41  impinges on thermoelectric device  66  ( FIG.  1   ). In other words, thermoelectric device  66  of  FIG.  1    is an example thermoelectric device  16  of  FIG.  3   . 
     When main burner operation is called for in the intermittent pilot light system, pilot valve operator  12  is in a state such as de-energized where fuel flow through the pilot valve is secured (e.g., blocked), and the pilot flame is dormant. With the pilot flame dormant, thermoelectric device  16  is generating insufficient electrical power to cause valve operation through main valve operator  14 . As previously discussed, systems  10  and  400  are configured so that energy storage system  20  may deliver power sufficient to operate pilot valve operator  12 , but not sufficient to operate main valve operator  14 . Main valve operator  14  can only receive sufficient power for operation from thermoelectric device  16 . 
     System  10  and system  400  may initiate establishment of the dormant pilot flame by energizing pilot valve operator  12  using stored energy system  20 , and thereby initiating a pilot gas flow to a pilot burner such as pilot burner  41  ( FIG.  1   ). Energy storage system  20  may energize pilot valve operator  12  using rechargeable energy storage components, non-rechargeable energy storage components, or both. Similarly, system  10  and system  400  may energize ignition circuit  24  to cause pilot spark ignitor  32  to generate thermal energy. Similar to pilot burner  41  and pilot spark ignitor  56  of  FIG.  1   , pilot spark ignitor  32  may be in thermal communication with the pilot gas flow such that the pilot flame generates. With thermoelectric device  16  in thermal communication with the established pilot flame, thermoelectric device  16  generates electrical energy from the thermal energy of the pilot flame and provides this electrical energy to main valve operator  14 . Main valve operator  14  actuates a main valve such as main valve  44  (FIG.  1 ), providing a main fuel flow to a main burner such as main burner  48  ( FIG.  1   ). The established pilot flame is in thermal communication with the main fuel flow and generates combustion of the main fuel flow. 
     Acting in this manner, system  10  and system  400  may ensure that a pilot flame is established prior to initiating main fuel flow to a main burner. Ensuring that the pilot flame is established prior to initiating main fuel flow to the burner avoids situations leading to discharges of uncombusted main fuel into surrounding environments. 
     Further, while main burner operation is required and the pilot flame remains established, system  10  may be configured to allow thermoelectric device  16  to provide power to pilot valve operator  12  through convertor  18 , electrical line  39 , and electrical connection  38 . System  10  may also be configured to allow thermoelectric device  16  to provide power to stored energy system  20  through converter  18 , electrical line  39 , and electrical connection  40 , replenishing the stored energy utilized to initially open the pilot valve. In examples, system  10  may be configured to allow thermoelectric device  16  to provide power to one or more of ignition circuit  24 , pilot spark ignitor  32 , and microcontroller  22 . Additionally, while main burner operation is required and the pilot flame remains established, system  400  ( FIG.  4   ) may be configured to allow thermoelectric device  16  to provide power to pilot valve operator  12  through electrical line  436  and electrical connection  38 . System  400  may also be configured to allow thermoelectric device  16  to provide power to stored energy system  20  through electrical line  436  and electrical connection  40 , replenishing the stored energy utilized to initially open the pilot valve. In examples, system  400  may be configured to allow thermoelectric device  16  to provide power to one or more of ignition circuit  24 , pilot spark ignitor  32 , and microcontroller  22 . 
     Additionally, system  10  and system  400  may be configured such that thermoelectric device  16  and power source  31  are the sole sources of power input for one or more of convertor  18  or converter  418 , microcontroller  22 , energy storage system  20 , pilot valve operator  12 , main valve operator  14  or  414 , ignition circuit  24 , or pilot spark ignitor  32 . This configuration may be advantageous in a water heater system where an additional source of power is unavailable due to, for example, a water heater location removed from a line power source, or some other reason. 
     In examples, pilot valve operator  12  may operate a pilot servo valve. The pilot servo valve may be configured to control a pressure of a fluid acting on a fluid actuated valve operator, with the fluid valve operator isolating a fuel supply from the pilot burner. When the pilot servo valve acts to increase or decrease a pressure of the fluid, the fluid actuated valve operator may establish fluid communication between the fuel supply and the pilot burner, establishing the pilot gas flow. Similarly, in examples main valve operator  14  ( FIG.  3   ) or  414  ( FIG.  4   ) may operate a main servo valve. The main servo valve may be configured to control a pressure of a fluid acting on a second fluid actuated valve operator, with the second fluid valve operator isolating a fuel supply from the main burner. When the main servo valve acts to increase or decrease a pressure of the fluid, the fluid actuated valve operator may establish fluid communication between the fuel supply and the main burner, establishing a main gas flow. 
     For example, Pilot valve operator  12  may be configured to cause operation of servo valve  134  ( FIGS.  2 A- 2 C ). In examples, pilot valve operator  12  is a component of servo valve  134 , such as a solenoid configured to influence the position of a valve stem of servo valve  134 , or some other component. Main valve operator  14  ( FIG.  3   ) or  414  ( FIG.  4   ) may be configured to cause operation of servo valve  152  ( FIGS.  2 A- 2 C ). In examples, main valve operator  14  ( FIG.  3   ) or  414  ( FIG.  4   ) is a component of servo valve  152 , such as a solenoid configured to influence the position of a valve stem of servo valve  152 , or some other component. Pilot valve operator  12  may cause servo valve  134  to reposition and main valve operator  14  ( FIG.  3   ) or  414  ( FIG.  4   ) may cause servo valve  152  to reposition, initiating the operations within valve body  120  discussed earlier. 
     In examples, when a flame such as the pilot flame is in thermal communication with a gas flow, or a gas flow is in thermal communication with a flame, this means the flame generates a heat flux and the heat flux impinges on some portion of the gas flow. In examples, the heat flux of the flame is sufficient to generate combustion within the portion of the gas flow. In examples, when the pilot spark ignitor is in thermal communication with a gas flow, this means that when the pilot spark ignitor generates an igniting energy such as a heat flux or electrical discharge, and some portion of the igniting energy impinges on some portion of the gas flow. In examples, the igniting energy of the pilot spark ignitor is sufficient to generate combustion within the portion of the gas flow. In examples, when thermoelectric device  16  is in thermal communication with a flame, the flame generates a heat flux and some portion of the heat flux impinges on some part of thermoelectric device  16 . In examples, the heat flux of the flame is sufficient to cause thermoelectric device  16  to convert some portion of the heat flux into electrical energy. In examples, when a temperature sensing device is in thermal communication with a body of water, this means a change in the temperature of the body of water affects the operating behavior of the temperature sensing device. 
     As discussed, system  10  and system  400  may comprise microcontroller  22 . Microcontroller  22  may comprise a processor, memory and input/output (I/O) peripherals. In examples, microcontroller  22  is configured to establish electrical contact between energy storage system  20  and pilot valve operator  12 . In an example, the first electronic device  26  is configured to establish electrical contact between energy storage system  20  and pilot valve operator  12 , and microcontroller  22  is configured to utilize first electronic device  26  to establish the electrical contact. In some examples, microcontroller  22  is configured to terminate electrical contact between energy storage system  20  and pilot valve operator  12 . In an example, first electronic device  26  may be likewise configured to terminate electrical contact between energy storage system  20  and pilot valve operator  12 , and microcontroller  22  may be configured to utilize first electronic device  26  to terminate the electrical contact. First electronic device  26  may be similarly configured to maintain or terminate electrical contact between thermoelectric device  16  and pilot valve operator  12 , and microcontroller  22  may be configured to utilize first electronic device  26  to maintain or terminate the electrical contact. 
     Microcontroller  22  may be is configured to establish electrical contact between thermoelectric device  16  and main valve operator  14  ( FIG.  3   ) or main valve operator  414  ( FIG.  4   ). In an example, the second electronic device  28  is configured to establish electrical contact between thermoelectric device  16  and main valve operator  14  or main valve operator  414 , and microcontroller  22  is configured to utilize second electronic device  28  to establish the electrical contact. In some examples, microcontroller  22  is configured to terminate electrical contact between thermoelectric device  16  and main valve operator  14  or main valve operator  414 . In an example, second electronic device  28  is likewise configured to terminate electrical contact between thermoelectric device  16  and main valve operator  14  or main valve operator  414 , and microcontroller  22  is configured to utilize second electronic device  28  to terminate the electrical contact. 
     In some examples, microcontroller  22  is configured to establish electrical contact between power source  31  and energy storage system  20 . In an example, the third electronic device  30  is configured to establish electrical contact between power source  31  and energy storage system  20 , and microcontroller  22  is configured to utilize third electronic device  30  to establish the electrical contact. Microcontroller  22  may be configured to terminate electrical contact between power source  31  and energy storage system  20 . In an example, third electronic device  30  is likewise configured to terminate electrical contact between power source  31  and energy storage system  20 , and microcontroller  22  is configured to utilize third electronic device  30  to terminate the electrical contact. 
     In some examples, microcontroller  22  is configured to establish electrical contact between power source  31  and microcontroller  22 . In an example, the fourth electronic device  47  is configured to establish electrical contact between power source  31  and microcontroller  22 , and microcontroller  22  is configured to utilize fourth electronic device  47  to establish the electrical contact. Microcontroller  22  may be configured to terminate electrical contact between power source  31  and microcontroller  22 . In an example, fourth electronic device  47  is likewise configured to terminate electrical contact between power source  31  and microcontroller  22 , and microcontroller  22  is configured to utilize fourth electronic device  47  to terminate the electrical contact. 
     In some examples, microcontroller  22  is configured to establish electrical contact between ignition circuit  24  and energy storage system  20 . In an example, a fifth electronic device  49  is configured to establish electrical contact between ignition circuit  24  and energy storage system  20 , and microcontroller  22  is configured to utilize fifth electronic device  49  to establish the electrical contact. Microcontroller  22  may be configured to terminate electrical contact between ignition circuit  24  and energy storage system  20 . In an example, fifth electronic device  49  is likewise configured to terminate electrical contact between ignition circuit  24  and energy storage system  20 , and microcontroller  22  is configured to utilize fifth electronic device  49  to terminate the electrical contact. First electronic device  26  may be similarly configured to maintain or terminate electrical contact between thermoelectric device  16  and ignition circuit  24 , and microcontroller  22  may be configured to utilize first electronic device  26  to maintain or terminate the electrical contact. 
     First electronic device  26 , second electronic device  28 , third electronic device  30 , fourth electronic device  47 , and fifth electronic device  49  may each be an apparatus sufficient to establish, maintain, and terminate electrical contact between two portions of an electrical system in response to a signal from microcontroller  22 . For example, first electronic device  26 , second electronic device  28 , and/or third electronic device  30  may comprise a field effect transistor (FET), a relay, a separate switching circuit, or any other device capable of establishing and terminating electrical contact in response to a signal. 
     In an example, microcontroller  22  is configured to recognize a requirement for main burner operation and in response, establish electrical contact between energy storage system  20  and pilot valve operator  12 , and establish electrical contact between thermoelectric device  16  and main valve operator  14  ( FIG.  3   ), or between converter  418  and main valve operator  414  ( FIG.  4   ). In some examples, microcontroller  22  responds by utilizing first electronic device  26  to establish the electrical contact between energy storage system  20  and pilot valve operator  12 . Microcontroller  22  may respond by utilizing second electronic device  28  to establish the electrical contact between thermoelectric device  16  and main valve operator  14  ( FIG.  3   ), or between converter  418  and main valve operator  414  ( FIG.  4   ). Microcontroller  22  may be configured establish electrical connection between ignition circuit  24  and energy storage system  20 , to prompt ignition circuit  24  to cause pilot spark ignitor  32  to generate an igniting energy such as an electrical discharge. Microcontroller  22  may be configured to utilize fifth electronic device  49  to establish the electrical connection between ignition circuit  24  and energy storage system  20  for the igniting energy. In some examples, microcontroller  22  may receive a signal indicative of a temperature from a temperature sensor such as temperature sensing device  62  ( FIG.  1   ), and microcontroller  22  may recognize the requirement for main burner operation based on the indicative signal. In examples, temperature sensing device  62  may be configured to provide an analog signal indicative of a temperature to an analog-to-digital (A/D) converter, and the A/D converter may provide a digital signal to microcontroller  22 . 
     When microcontroller  22  recognizes the requirement for main burner operation, microcontroller  22  may be configured to initially utilize electrical power from power source  31  to establish the electrical connections necessary to establish a pilot flame. As thermoelectric device  16  begins generating electrical energy in response to the pilot flame, microcontroller  22  may be configured to shift its power supply from power source  31  to electrical energy provided by thermoelectric device  16  and delivered via, for example, converter  45 . Microcontroller  22  may be configured to terminate an electrical connection between microcontroller  22  and power source  31  using fourth electronic device  47  while thermoelectric device  16  generates and provides electrical energy through converter  45 . 
     While the main burner requirement is ongoing, microcontroller  22  may be configured to maintain the electrical connection between thermoelectric device  16  and pilot valve operator  12  using first electronic device  26 , in order that thermoelectric device  16  may provide the electrical power necessary to maintain pilot valve operator  12  energized. Similarly, while the main burner requirement is ongoing, microcontroller  22  may be configured to maintain the electrical connection between thermoelectric device  16  and ignition circuit  24  using fifth electronic device  49 , in order that thermoelectric device  16  may provide the igniting energy to ignition circuit  24 . 
     In an example, microcontroller  22  is similarly programmed to recognize a requirement to secure the main burner, and in response, terminate electrical contact between thermoelectric device  16  (and energy storage system  20 ) and pilot valve operator  12 , and terminate electrical contact between thermoelectric device  16  and main valve operator  14  ( FIG.  3   .), or between converter  418  and main valve operator  414  ( FIG.  4   ). Microcontroller  22  may be configured to terminate electrical contact between ignition circuit  24  and thermoelectric device  16  (and energy storage system  20 ), to cease causing pilot spark ignitor  32  to generate igniting energy. As discussed, microcontroller  22  may utilize first electronic device  26  to terminate electrical contact between pilot valve operator  12  and thermoelectric device  16  (and energy storage system  20 ). Microcontroller  22  may utilize second electronic device  28  to terminate electrical contact between thermoelectric device  16  and main valve operator  14  ( FIG.  3   .) or main valve operator  414  ( FIG.  4   ). Microcontroller  22  may utilize fifth electronic device  49  to terminate electrical contact between ignition circuit  24  and thermoelectric device  16  (and energy storage system  20 ). 
     In some examples, microcontroller  22  is configured to periodically wake and monitor a status of system  10  ( FIG.  3   ) or system  400  ( FIG.  4   ). In some examples, microcontroller  22  is configured to selectively actuate components within system  10  or system  400  in response to a status of energy storage system  20 , or another component. For example, microcontroller  22  may be configured to periodically wake and determine an available voltage level in energy storage system  20 . Microcontroller  22  may determine if the available voltage is sufficient for the operations leading to establishment of a pilot flame as discussed, or if energy storage system  20  would benefit from reception of additional stored energy from power source  31 . For example, microcontroller  22  might compare the available voltage to a setpoint, and determine additional energy to energy stored system should or should not occur based on a comparison of the available voltage and the setpoint. If microcontroller  22  determines additional energy to energy storage system is needed, microcontroller  22  may establish electrical contact between power source  31  and energy storage system  20  to allow power source  31  to provide recharging power to energy storage system  20 . As discussed, when thermoelectric device  16  is generating electrical energy, thermoelectric device  16  may also provide a portion of the electrical energy to stored energy system  20  in order to replenish the stored energy system. 
     In examples, one or more of pilot valve operator  12 , main valve operator  14 , or main valve operator  414  are millivoltage automatic valve operators. In examples, one or more of pilot valve operator  12  or main valve operator  14  are configured to alter the position of a valve when thermoelectric device  16  generates electrical power at a voltage of 800 mV or less (e.g., a voltage in a range of 800 mV to 400 mV). In examples, one or more of pilot valve operator  12  or main valve operator  14  are configured to alter the position of a valve when pilot valve operator  12  or main valve operator  14  receives a current of 50 mA or less (e.g., a current in a range of 25 mA to 50 mA). The electrical resistance of main valve operator  414  is such that main valve operator  414  may only be sufficiently energized to actuate the necessary valve when thermoelectric device  16  is generating a voltage (i.e., the pilot flame is lit) and converter  418  is stepping up the voltage from the generated level to a level sufficient to cause main valve operator  414  to actuate. In examples, one or more of pilot valve operator  12 , main valve operator  14 , or main valve operator  414  cause the opening of a valve when in the energized state. In some examples, one or more of pilot valve operator  12 , main valve operator  14 , or main valve operator  414  cause the closing of a valve when in the de-energized state. In some examples, one or more of pilot valve operator  12 , main valve operator  14 , or main valve operator  414  control the energizing of an electromechanical device such as a solenoid valve. 
     Power source  31  may be one or more devices capable of storing electrical energy, such as a battery, a capacitor, one or more series connected batteries and/or another device capable of storing electrical energy. Power source  31  may comprise a lithium battery Power source  31  may comprise a supercapacitor. Power source  31  may comprise an electrochemical double-layer capacitor (EDLC) Power source  31  may comprise one or more of a double-layer capacitor, a pseudocapacitor, or a hybrid capacitor. In examples, power source  31  may comprise an initial energy storing component which may be removed from a water heater control system and replaced in the water heater control system with a subsequent energy storing component. The energy storing component may be rechargeable. Power source  31  may be charged to a specified voltage prior to installation of the associated water heater. 
     In examples, convertor  18  and convertor  418  may be a power convertor which receives electrical power is a first form and converts the electrical power to another form. Converter  18  and convertor  418  may be an electronic circuit, electronic device, or electromechanical device. In examples, converter  18  receives a first voltage received from thermoelectric device  16  and provides a second voltage to electrical line  39 . In examples, converter  418  receives a first voltage received from thermoelectric device  16  and provides a second voltage to electrical line  434 . In examples, the second voltage is greater than the first voltage. Converter  418  may be configured to generate a voltage greater than that generated by thermoelectric device  16 . In examples, converter  418  may be configured to generate a voltage in a range of 3 VDC-6 VDC, or some other voltage greater than that produced by thermoelectric device  16 . For example, convertor  18  or convertor  418  might receive a first voltage of about 0.7 VDC (700 mV) from thermoelectric device  16  and provide a voltage of about 3.3 VDC to electrical line  39  or electrical line  434  respectively. In examples, convertor  18  or convertor  418  is a DC step-up convertor. 
     In examples, thermoelectric device  16  comprises one or more components which generate an output voltage proportional to a local temperature difference or temperature gradient, such as a thermopile, thermocouple, or other thermoelectric generator. Thermoelectric device  16  may comprise a thermoelectric material. Thermoelectric device  16  may comprise a plurality of thermocouples connected in series or in parallel. Thermoelectric device  16  may comprise one or more thermocouple pairs. In examples, a heat flux from a pilot flame generates a temperature gradient, and thermoelectric device  16  generates a DC voltage in response to the temperature gradient. 
     In examples, energy storage system  20  comprises one or more of a capacitor, a battery, or a capacitor and a battery. Energy storage system  20  may comprise a supercapacitor. Energy storage system  20  may comprise an electrochemical double-layer capacitor (EDLC). Energy storage system  20  may comprise one or more of a double-layer capacitor, a pseudocapacitor, or a hybrid capacitor. Energy storage system  20  may comprise a lithium battery. In examples, the energy storage system  20  may comprise an energy storage component which may be removed from water heater control system  10  and replaced in water heater control system  10  with a subsequent energy storage component. The energy storage component may be rechargeable such that the energy storage component is configured to have its stored electrical energy restored through a permanent or temporary connection to a power supply, for example thermoelectric device  16  or some other power supply. The energy storage component may be non-rechargeable. 
     In examples, microcontroller  22  may include any one or more of a microcontroller (MCU), e.g. a computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals, a microcontroller (μP), e.g. a central processing unit (CPU) on a single integrated circuit (IC), a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a system on chip (SoC) or equivalent discrete or integrated logic circuitry. A processor may be integrated circuitry, i.e., integrated processing circuitry, and that the integrated processing circuitry may be realized as fixed hardware processing circuitry, programmable processing circuitry and/or a combination of both fixed and programmable processing circuitry. 
     Example techniques of generating a main burner flame is illustrated at  FIG.  5   . The technique may include initiating a first gas flow by energizing a first valve operator using an energy storage system ( 170 ). In examples, the technique initiates a pilot gas flow by energizing pilot valve operator  12  using energy storage system  20 . The technique may include prompting a pilot ignition circuit to generate a pilot flame using the first gas flow ( 172 ). In examples, the technique prompts pilot ignition circuit  24  to cause pilot spark ignitor  32  in thermal communication with the first gas flow to generate a pilot flame. 
     The technique may include allowing a device to convert thermal energy from the pilot flame into electrical energy ( 174 ). In examples, the technique allows thermoelectric device  16  in thermal communication with the pilot flame to generate electrical energy from some portion of the thermal energy received from the pilot flame. The technique may include initiating a second gas flow using a first portion of the electrical energy ( 176 ). In examples, the technique initiates a main gas flow by energizing main valve operator  14  using a first portion of the electrical energy. The technique may include storing a second portion of the electrical energy. In examples, the technique provides a second portion of the electrical energy to energy storage system  20 . 
     The technique may include porting the second gas flow to a burner in thermal communication with the pilot flame ( 168 ). In examples, the technique ports the main gas flow to main burner  48 , which is configured to establish thermal communication between the main gas flow and the pilot flame, thereby generating the main burner flame. 
     In examples, the technique may include recognizing a temperature signal using a microcontroller, and responding to the temperature signal by utilizing the microcontroller to establish electrical communication between the energy storage system and the first valve operator. The technique may include reacting to the temperature signal by utilizing the microcontroller to prompt the pilot ignition circuit to cause the pilot spark ignitor to generate the pilot flame. In examples, the technique may include acknowledging the temperature signal by utilizing the microcontroller to establish electrical contact between the device and the second valve operator. 
     In one or more examples, functions described herein may be implemented in hardware, software, firmware, or any combination thereof. For example, the various components and functions of  FIGS.  1 - 5    may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a tangible computer-readable storage medium and executed by a processor or hardware-based processing unit. 
     Instructions may be executed by one or more processors, such as one or more DSPs, general purpose microcontrollers, ASICs, FPGAs, or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor,” as used herein, such as may refer to any of the foregoing structure or any other structure suitable for implementation of the techniques described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements. 
     The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC) or a set of ICs (e.g., a chip set). Various components, modules, or units are described in this disclosure to emphasize functional aspects of devices configured to perform the disclosed techniques, but do not necessarily require realization by different hardware units. Rather, as described above, various units may be combined in a hardware unit or provided by a collection of interoperative hardware units, including one or more processors as described. 
     The present disclosure includes the following examples: 
     Example 1 
     A water heater comprising: a power source that is non-rechargeable; a controller configured to receive power from the power source; an energy storage system comprising a rechargeable power supply and configured to provide power to one or more components of the water heater, wherein the water heater is configured to prevent the controller from receiving power from the rechargeable power supply; and a thermoelectric device configured to provide power to recharge the rechargeable power supply, wherein the thermoelectric device is configured to generate power in response to a pilot flame in proximity to the thermoelectric device. 
     Example 2 
     The water heater of example 1, wherein the rechargeable power supply is configured to receive power for recharging from the power supply in instances when there is no pilot flame and a power level of the rechargeable power supply is less than a threshold. 
     Example 3 
     The water heater of example 1 or 2, wherein the controller is configured to selectively receive power from at least one of the power source or the thermoelectric device. 
     Example 4 
     The water heater of any of examples 1-3, further comprising: a first valve operator configured to cause a first gas flow, wherein the first valve operator is coupled to receive power from the energy storage system, the power source, or both the energy storage system and the power source when the thermoelectric device is not generating power and coupled to receive power generated by the thermoelectric device when the thermoelectric device is generating power; an ignition circuit is configured to cause the pilot flame using the first gas flow; a second valve operator coupled to receive power generated by the thermoelectric device, wherein the second valve operator is configured to cause a second gas flow; and a burner configured to generate a main burner flame using the pilot flame and the second amount of gas flow. 
     Example 5 
     The water heater of example 4, wherein the ignition circuit is coupled to receive power from the energy storage system, the power source, or both the energy storage system and the power source when the thermoelectric device is not generating power and coupled to receive power generated by the thermoelectric device when the thermoelectric device is generating power. 
     Example 6 
     The water heater of examples 4 or 5, wherein the water heater is configured to prevent the second valve operator from receiving power from the energy storage system. 
     Example 7 
     The water heater of any of examples 4-6, wherein: the first valve operator requires a first voltage to cause the first gas flow, the second valve operator requires a second voltage to cause the second gas flow, the first voltage is less than the second voltage, and the thermoelectric device is configured to provide power at a voltage greater than or equal to the first voltage and less than the second voltage. 
     Example 8 
     The water heater of any of examples 1-7, wherein the controller is configured to establish electrical contact between the power source and the energy storage system to provide a recharging power from the power source to the energy storage system. 
     Example 9 
     The water heater of any of examples 1-8, wherein the controller is configured to receive power from the thermoelectric device when the thermoelectric device is generating power. 
     Example 10 
     The water heater of any of examples 1-9, wherein the controller is configured to: receive a signal indicative of a temperature; establish, in response to the signal indicative of the temperature, electrical contact between the energy storage system and a first valve operator, wherein the first valve operator is configured to cause a first gas flow control; and initiate, in response to the signal indicative of the temperature, electrical contact between the thermoelectric device and a second valve operator, wherein the second valve operator is configured to cause a second gas flow, wherein a mass flow rate of the second gas flow is greater than a mass flow rate of the first gas flow. 
     Example 11 
     The water heater of example 10, further comprising: a first electronic device configured to establish electrical contact between the energy storage system and the first valve operator; and a second electronic device configured to establish electrical contact between the thermoelectric device and the second valve operator, wherein the microcontroller is configured to utilize the first electronic device to establish electrical contact between the energy storage system and the first valve operator in response to the signal indicative of the temperature, and wherein the microcontroller is configured to utilize the second electronic device to initiate electrical contact between the thermoelectric device and the second valve operator in response to the signal indicative of the temperature. 
     Example 12 
     The water heater of any of examples 1-11, wherein the controller is configured to: determine an available voltage level in the energy storage system; determine whether the energy storage system requires additional charge based on the available voltage level; and establish, based on the energy system requiring additional charge, electrical contact between the power source and the energy storage system to provide the recharging power. 
     Example 13 
     The water heater of example 12, further comprising an electronic device configured to establish electrical contact between the power source and the energy storage system, wherein the microcontroller is configured to utilize the electronic device to establish electrical contact between the power source and the energy storage system to provide the recharging power. 
     Example 14 
     The water heater of any of examples 1-13, wherein the water heater controller is configured to prevent the controller from receiving power from the energy storage system. 
     Example 15 
     A water heater system comprising: a first valve operator, wherein the first valve operator initiates a first gas flow when energized; an energy storage system coupled to energize the first valve operator; a power source coupled to recharge the energy storage system; a pilot ignition circuit configured to cause a pilot spark ignitor to generate a pilot flame using the first gas flow; a second valve operator, wherein the second valve operator initiates a second gas flow when energized, wherein the second gas flow is greater than the first gas flow, and wherein the second valve operator cannot be energized from the energy storage system; and a thermoelectric device that converts thermal energy from the pilot flame into electrical energy, the thermoelectric device coupled to provide a first portion of the electrical energy to energize the second valve operator and the thermoelectric device coupled to provide a second portion of the electrical energy to the energy storage system. 
     Example 16 
     The water heater of example 15, further comprising a controller, wherein the water heater system is configured to provide electrical power from the power source to the controller when the thermoelectric device is not generating the electrical energy, and wherein the water heater system is configured to provide electrical power from the thermoelectric device to the microcontroller when the thermoelectric device is generating the electrical energy. 
     Example 17 
     The water heater of example 15 or 16, wherein the controller is configured to: receive a signal indicative of a temperature; establish, in response to the signal indicative of the temperature, electrical contact between the energy storage system and the first valve operator; prompt, in response to the signal indicative of the temperature, the pilot ignition circuit to cause the pilot spark ignitor to generate the pilot flame using the first gas flow; and initiate, in response to the signal indicative of the temperature, electrical contact between the thermoelectric device and the second valve operator. 
     Example 18 
     The water heater of any of examples 15-17, further comprising a controller configured to: determine an available voltage level in the energy storage system; determine if the energy storage system requires additional charge based on the available voltage; and establish, based on the energy system requiring additional charge, electrical contact between the energy storage system and the power source. 
     Example 19 
     A method comprising: providing power to one or more components of the water heater using an energy storage system comprising a rechargeable power supply; recharging the rechargeable power supply using a thermoelectric device configured to generate power from a pilot flame; preventing a controller from receiving power from the energy storage system; and providing power to the controller using a non-rechargeable power source. 
     Example 20 
     The method of example 19, further comprising: determining, using the controller, a voltage level of the energy storage system while the thermoelectric device is not generating power from the pilot flame; and recharging, based on the determined voltage level, the energy storage system by establishing an electrical connection between the energy storage system and the non-rechargeable power source. 
     Various examples have been described. These and other examples are within the scope of the following claims.