| 摘要 |
PROBLEM TO BE SOLVED: To provide a water heater which can suppress generation of hunting even when a gap occurs between an output which can be dealt with at one combustion stage and an output which can be dealt with at the other combustion stage.SOLUTION: In the case where an unadjustable range, which is a numerical range surpassing an upper limit value and below a lower limit value, has occurred between an upper limit value of a combustion output in an i-th combustion stage and a lower limit value of the combustion output in an i+1-th combustion stage, a controller which a water heater has determines that such an unadjustable range has occurred (S310, S340). In the case where a necessary combustion output is in the unadjustable range, a switching valve, a proportional control valve and a blower are controlled so that an actual combustion output is fixed at one of the upper limit value of the combustion output in the i-th combustion stage, and the lower limit value of the combustion output in the i+1-th combustion stage (S340: YES).SELECTED DRAWING: Figure 7 |
