Temperature control system of gas-fired water heater

Abstract

A temperature control system of a gas-fired water heater includes a cold water pipe connected to one side of a heat exchanger and a hot water pipe connected to another side of the heat exchanger. A circulation pump is mounted to a water return pipe, which has two ends respectively connected to the hot water pipe and the heat exchanger to direct and return hot water from the hot water pipe back to the heat exchanger. When a hot water faucet is opened to activate a combustion operation of the gas-fired water heater, the circulation pump is set in continuous operation to pump water from the water return pipe for returning back to the heat exchanger, so that the returned hot water can be mixed, in the heat exchanger, with cold water supplied through the cold water pipe in order to achieve a set temperature.

I claim: 
     
         1 . A temperature control system of a gas-fired water heater, comprising:
 a heat exchanger, which heats and converts cold water into hot water;   a cold water pipe, which is connected to one side of the heat exchanger to supply cold water to the heat exchanger;   a hot water pipe, which is connected to another side of the heat exchange to output hot water generated by the heat exchanger;   a circulation pump, which is mounted to a water return pipe, the water return pipe having two ends respectively connected to the hot water pipe and the heat exchanger to direct and return hot water contained in the hot water pipe back to the heat exchanger.   
     
     
         2 . The temperature control system of the gas-fired water heater according to  claim 1 , wherein the heat exchanger comprises a water tank, which has a capacity that is less than or equal to 10 gallons. 
     
     
         3 . The temperature control system of the gas-fired water heater according to  claim 1 , wherein the water return pipe is connected to the hot water pipe and the heat exchanger to form an internal circulation such that the connection between the water return pipe and the heat exchanger forms an inlet port of the returned water, which is not at the same location as an inlet port of cold water formed as the connection between the cold water pipe and the heat exchanger. 
     
     
         4 . The temperature control system of the gas-fired water heater according to  claim 1 , wherein the heat exchanger is coupled to a combustion blower, wherein the combustion blower is connected to a fuel gas pipe and the fuel gas pipe comprises a fuel gas valve for supplying fuel gas to the heat exchanger to serve as a combustion heat source to serve as a combustion heat source.