Gas-fired heating device having a thermopile

Abstract

A gas-fired heating device having a burner, a pilot to provide a pilot flame, a thermopile thermally coupled to the pilot flame and configured to generate a power in response to the pilot flame, an electrically controlled gas valve to control the flow of gas to at least one of the pilot and the burner, and a controller electrically coupled to the thermopile and the gas valve. The controller receives and is powered by the power from the thermopile. The controller initiates closing of the gas valve after a monitored component of the power, such as a voltage, traverses a threshold.

1 . A gas water heater comprising:
 a burner;   a pilot to provide a pilot flame;   a thermopile thermally coupled to the pilot flame and configured to generate a power in response to the pilot flame;   an electrically controlled gas valve to control the flow of gas to at least one of the pilot and the burner;   a controller electrically coupled to the thermopile and the gas valve, the controller to receive and be powered by the power from the thermopile, and to initiate closing of the gas valve after a monitored component of the power traverses a threshold.   
     
     
         2 . The gas water heater of  claim 1  wherein the threshold indicates an abnormal flame state for the pilot flame. 
     
     
         3 . The gas water heater of  claim 1  wherein the threshold indicates the detection of a possible flammable vapor event. 
     
     
         4 . The gas water heater of  claim 1  wherein the threshold indicates the detection of a possible lint, dust, and oil (LDO) filter blockage event. 
     
     
         5 . The gas water heater of  claim 1  wherein the threshold indicates the gas water heater has a possible improper ventilation event. 
     
     
         6 . The gas water heater of  claim 1  wherein the threshold indicates the gas water heater has a possible overheating event. 
     
     
         7 . The gas water heater of  claim 1  wherein the controller includes a processor and memory. 
     
     
         8 . The gas water heater of  claim 1  wherein the power from the thermopile includes a voltage, and wherein the monitored component includes the voltage. 
     
     
         9 . The gas water heater of  claim 8  wherein the threshold for the monitored component is between about 275 and 450 millivolts. 
     
     
         10 . The gas water heater of  claim 1  wherein the controller includes an electronic device and the gas valve includes an electronically controlled gas valve. 
     
     
         11 . The gas water heater of  claim 10  wherein the power for opening the electronically controlled gas valve originates from the power from the thermopile. 
     
     
         12 . A safety system for use in a gas water heater including a burner, a pilot, and a gas valve, the safety circuit comprising:
 a thermopile to be thermally coupled to a pilot flame of the pilot and configured to generate a power having a voltage in response to the pilot flame thermally interacting with the thermopile;   a controller electrically coupled to the thermopile and for connecting to the electronically controlled gas valve, the controller to be powered by the power from the thermopile, to monitor the voltage to determine a pilot flame status, and to control the gas valve based on the pilot flame status.   
     
     
         13 . The safety system of  claim 12  wherein the pilot flame status includes a status indicating a normal flame burn. 
     
     
         14 . The safety system of  claim 12  wherein the pilot flame status includes a status indicating a possible abnormal flame burn. 
     
     
         15 . The safety system of  claim 14  wherein the controller initiates the closing of the gas valve after the pilot flame indicates the possible abnormal flame burn. 
     
     
         16 . The safety system of  claim 14  wherein the controller determines a possible abnormal pilot flame burn when the voltage is between about 275 and 450 millivolts. 
     
     
         17 . The safety system of  claim 12  wherein the controller includes a processor and memory and wherein the memory includes diagnostic thresholds for indicating the possible abnormal flame burn. 
     
     
         18 . The safety system of  claim 12  wherein the safety circuit further includes the gas valve, and wherein the gas valve includes an electronically controlled gas valve. 
     
     
         19 . The safety system of  claim 18  wherein the power for opening the electronically controlled gas valve originates from the power from the thermopile. 
     
     
         20 . A method for controlling a gas water heater including a burner, a pilot, a thermopile, a controller, and an electronically controlled gas valve, the method comprising:
 establishing a pilot flame with the pilot;   powering the controller with a power generated by the thermopile thermally interacting with the pilot flame, the power having a voltage;   monitoring the voltage with the controller;   
       detecting a possible LDO filter blockage event or a possible flammable vapor event with the monitored voltage;
 generating a shutdown signal with the controller in response to detecting the possible LDO filter blockage event or the possible flammable vapor event; and 
 closing the electronically controlled gas valve in response to the shutdown signal. 
 
     
     
         21 . The method of  claim 20  and further comprising opening the electronically controlled gas valve with power originating from the thermopile.