| 摘要 |
PROBLEM TO BE SOLVED: To prevent gas from being supplied more than necessary to a burner by fixing a gas supply pipe between a proportional control valve and the burner with a flow sensor for detecting the flow rate of gas being supplied to the burner and feedback controlling the opening of the proportional control valve depending on the detection signal of the flow sensor. SOLUTION: The combustion drum 1 of a hot water supply apparatus comprises a gas burner 2 coupled with a gas supply pipe 3. The gas supply pipe 3 is provided with a safety valve 31 coupled with a proportional control valve 32. The proportional control valve 32 controls the opening variably with a control signal to regulate the quantity of gas being supplied to the gas burner 2 continuously. A controller 7 sets the opening of a water supply valve 52 to supply a heat exchanger 10 with water when the quantity and temperature of hot water supply are set. A signal corresponding to the set opening is delivered to the water supply valve 52 and, at the same time, actual water supply is detected by a flowmeter 51 in order to regulate the opening of the water supply valve 52 finely through feedback control thus regulating the quantity of gas being supplied to the gas burner accurately.
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