PURPOSE: To eliminate special operation of switch for freeze preventing operation and consequently improve the operability of the water heater by a method wherein a circulating pump is controlled in response to the detected output of a detector detecting the ambient temperature in case that an operating switch is OFF.
CONSTITUTION: The gas hot water supply and heating equipment heats respective rooms 3W3" by sending hot water heated in the heat exchanger 5 of a heat source unit 1 at the heating operation to heat exchangers 7W9 equipped within the rooms 3W3" respectively by means of the circulating pump 6. At this time, a controlling circuit 17 controls a shut-off valve 14, which is concerned with said heating operation, a controlling valve 15, the circulating pump 6 and an igniter by means of the input signal of a heating operation switch 18. Accordingly, when the combustion is stopped or the shut-off valve is shut-off, the output of the ambient temperature detector 19 is brought into the controlling circuit 17. After that, when the ambient temperature is lower than the predetermined value, the circulating pump 6 is put into operation for preventing freezing of the water within the piping by circulating said water.
MURAKAMI HIROKUNI
FUJIEDA HIROSHI
