Hot-water supply apparatus, anti-freezing method thereof, and anti-freezing program thereof

Abstract

A hot-water supply apparatus is an apparatus which has a primary heat exchanger absorbing sensible heat of combustion exhaust and a secondary heat exchanger absorbing latent heat of the combustion exhaust, and improves a freezing prevention function of the hot-water supply apparatus at a cold period. Further, this apparatus has a temperature detection means (temperature sensors) which detects a freezing prevention temperature, a combustion means (a burner group) which supplies combustion exhaust generated by combustion to the primary and secondary heat exchangers, an air supply means which supplies air to the combustion means, and a control means (a control unit) which makes the combustion means burn and drives the air supply means based on a detected temperature of the temperature detection means. When the temperature detection means detects the freezing prevention temperature, the combustion means is burned for a settled time to heat the primary heat exchanger, and the air supply means is driven to stream air from a side of the primary heat exchanger to the secondary heat exchanger for a given time after a combustion stop of the combustion means. By this, a side of the secondary heat exchanger is heated by remaining heat of the side of the primary heat exchanger.