| 摘要 |
PROBLEM TO BE SOLVED: To prevent vapor condensation of a reheating heat exchanger due to a decrease in combustion heat quantity of a bath burner caused by simultaneous combustion of a hot water supply burner and the bath burner in a composition water heater having a common proportional valve for both the supply burner and the bath burner. SOLUTION: A pump intermittent operation controller 50 is provided in a control apparatus 56. A data storage unit 52 stores a pump-off temperature TOFF of an output side of a reheating heat exchanger corresponding to a temperature immediately before generation of vapor condensation of the exchanger and a higher pump-on temperature TON than the temperature TOFF. The controller 50 turns off a circulation pump 23 while keeping a bath burner burning when it is judged that the detected hot water temperature of an output side temperature sensor 44 of the exchanger is the TOFF or less, at the time when the pump 23 is turned on in simultaneous combustion, and turns on the pump 23 when it is judged that the detected hot water temperature is the TON or more for its pump-off period. It prevents the temperature drop of the exchanger to avoid the occurrence of vapor condensation of the exchanger. |
