| 摘要 |
PROBLEM TO BE SOLVED: To provide a water heater capable of effectively suppressing no-water burning of a heat exchanger when it is frozen. SOLUTION: A controller 9 of the water heater 1 stores two operation water amounts in advance, that is, a first operation water amount as a minimum operation water amount, and a second operation water amount set to be larger than the first operation water amount and set to be larger than the amount of water flowing through a bypass passage when the amount of water flowing through the heat exchanger being zero and the opening of a water amount adjustment valve being the minimum opening, and the first operation water amount is used as the minimum operation water amount (STEP 2) when the prescribed condition that there is the risk of freezing of the heat exchanger is not satisfied (STEP 7), and the opening of the water amount adjustment valve is made to be the minimum opening (STEP 4) and the second operation water amount is used as the minimum operation water amount (STEP 5) when the prescribed condition is satisfied (STEP 3). COPYRIGHT: (C)2011,JPO&INPIT
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