PROBLEM TO BE SOLVED: To provide a sterilization method in a hot water supply device that performs a sterilization operation for sterilizing hot water by a sterilizer while circulating the hot water in a reheating circuit after a lapse of a predetermined bathing period, using the hot water supply device equipped with the sterilizer interposed in the reheating circuit for circulating the hot water in a bathtub in a heat exchanger for reheating, and an automated drain plug for performing draining from the bathtub, capable of reducing an operation time of the sterilization operation and saving energy.SOLUTION: At the time when a bathing period has passed, hot water in a bathtub is drained by an automated drain plug in a predetermined amount. Then, non-heated water in a predetermined amount equal to the drainage amount is supplied to the bathtub and a sterilization operation is performed for a predetermined time.SELECTED DRAWING: Figure 2COPYRIGHT: (C)2017,JPO&INPIT【課題】浴槽内の湯を追い焚き用熱交換器との間に循環させる追い焚き回路に介設される殺菌装置と、浴槽からの排水を行う自動排水栓とを備える給湯装置を用い、所定の入浴期間経過後に追い焚き回路に湯を循環させつつ殺菌装置で湯を殺菌する殺菌運転を行う給湯装置における殺菌方法において、殺菌運転の運転時間を短縮して省エネルギー化を図ることができるようにする。【解決手段】入浴期間が経過したところで浴槽内の湯を自動排水栓により所定量排水し、その後、排水量に等しい所定量の非加熱の水を浴槽に注水してから殺菌運転を所定時間行う。【選択図】図2
