To prevent wasteful use of city water by a method wherein an amount of city water mixed in drain is kept at a proper value regardless of a fluctuation of a supply water pressure of city water supplied to a water flow passage 11, in a latent heat recovery type hot water supply apparatus comprising a discharge passage 18 to discharge drain generated at a heat-exchanger 12 inserted in the water flow passage 11; a branch passage 15 branched from the portion, situated upper stream from the heat-exchanger 12, of the water flow passage 11, linked to the discharge passage 18, and provided with an on-off value 16; and a value control device to open the on-off value 16 when a gas burner 21 to heat the heat-exchanger 12 effects combustion.
A constant flow regulating valve 31 to keep a flow rate at a constant value regardless of a water pressure change is inserted in a branch passage 15.
MORI KINJI
OKADA SADAO
TAJIMA NAOKI
Next Patent: WATER LEVEL DETECTING DEVICE FOR ELECTRIC WATER HEATER