| 摘要 |
PROBLEM TO BE SOLVED: To prevent heating of a hot water of a bathtub by a heat preservation combustion without expecting by controlling an execution of the heat preservation combustion and to improve an antifreezing effect by executably setting the heat preservation combustion when an antifreezing mode is made. SOLUTION: When a hot water of a bathtub Y is circulated to a heat exchanger P for the bathtub by a circulating pump 11 during a hot water output heat preservation mode, a heat of a heat exchanger Q for hot water output is derived to the exchanger P by a circulating flow of the hot water so that a sensed temperature of the exchanger Q become lower than a heat preservation starting temperature. During operating of the pump 11, a heat preservation combustion is stopped to prevent temperature rising of the hot water of the bathtub Y. When the pump 11 is stopped, the stop of the heat preservation combustion is released. However, during executing of an antifreezing mode, the combustion is set executable even during operating of the pump 11, and an antifreezing effect is improved.
|
