Safety system for a gas fueled water heater

Abstract

A system for monitoring temperature in the combustion chamber of a gas fueled water heater using a thermoelectric device placed near the gas burner. Based on the measured temperature, the water heater can determine whether abnormal operation is occurring that would require closing the flow of gaseous fuel to e.g., the main burner, pilot burner, or both.

1 . A gas fueled water heater, comprising:
 a tank for storage of water for heating;   a combustion chamber;   a gas burner positioned adjacent to the tank and within the combustion chamber, the gas burner configured for heating the water in the tank;   a valve controlling a flow of gaseous fuel to the gas burner;   a thermopile positioned within the combustion chamber near the gas burner; the thermopile configured to provide a signal representing temperature, TP, as measured in the combustion chamber;   a controller configured for
 receiving the signal from the thermopile, and 
 terminating a flow of gaseous fuel to the gas burner if the temperature TIP is the same or greater than a predetermined maximum temperature, TP MAX . 
   
     
     
         2 . The gas fueled water heater of  claim 1 , wherein the predetermined maximum temperature, TP MAX , is 1200° F. 
     
     
         3 . The gas fueled water heater of  claim 1 , wherein the predetermined maximum temperature, TP MAX , is 1300° F. 
     
     
         4 . The gas fueled water heater of  claim 1 , further comprising:
 a pilot burner for providing a pilot light to ignite the gas burner;   wherein the controller is further configured for terminating a flow of gaseous fuel to the pilot burner if the temperature TP is less than a predetermined temperature, TP PILOT .   
     
     
         5 . The gas fueled water heater of  claim 4 , wherein TP PILOT  is 500° F. 
     
     
         6 . The gas fueled water heater of  claim 4 , wherein TP PILOT  is 510° F. 
     
     
         7 . The gas fueled water heater of  claim 1 , wherein the thermopile provides energy to power the controller. 
     
     
         8 . The gas fueled water heater of  claim 1 , wherein the controller provides a signal to close the valve if the temperature TP is greater than the predetermined maximum temperature, TP MAX . 
     
     
         9 . The gas fueled water heater of  claim 1 , herein the controller provides a signal to close the valve if the temperature TP is greater than the predetermined maximum temperature, TP MAX  for at least a predetermined period of time Δt MAX . 
     
     
         10 . A method of operating a gas fueled water heater, the water heater having a combustion chamber and a thermopile for measuring temperature in the combustion chamber, the method comprising:
 generating a signal representing the temperature, TP, in the combustion chamber as measured by the thermopile; and   determining whether the temperature TP is the same or greater than a predetermined temperature TP MAX  and, if so, then
 terminating a flow gaseous fuel to a gas burner located in the combustion chamber. 
   
     
     
         11 . The method of operating a gas fueled water heater as in  claim 10 , further comprising terminating a flow of gaseous fuel to the gas burner in the combustion chamber if the temperature TP is the same or greater than TP MAX  for a predetermined period of time Δt MAX . 
     
     
         12 . The method of operating a gas fueled water heater as in  claim 10 , wherein the terminating a flow of gaseous fuel comprises closing a valve. 
     
     
         13 . The method of operating a gas fueled water heater as in  claim 10 , wherein TP MAX , is 1200° F. 
     
     
         14 . The method of operating a gas fueled water heater as in  claim 10 , wherein TP MAX , is 1300° F. 
     
     
         15 . The method of operating a gas fueled water heater as in  claim 10 , further comprising
 ascertaining whether temperature TP is less than a predetermined temperature T PPILOT  and, if so, then
 terminating a flow gaseous fuel to a pilot burner located in the combustion chamber. 
   
     
     
         16 . The method of operating a gas fueled water heater as in  claim 15 , wherein TP PILOT  is 500° F. 
     
     
         17 . The method of operating a gas fueled water heater as in  claim 15 , wherein TP PILOT  is 505° F.