| 摘要 |
PROBLEM TO BE SOLVED: To prevent a lot of unexpected hot water from being supplied from a tap for hot water, when water in a water passage pipe 2 is heated for a long time by an antifreeze electric heater due to ON-failure where the electric heater 3 operates even though it should not operate, by detecting the ON-failure as well as disconnection or short-circult failure of the electric heater 3.SOLUTION: An ON-failure sensing means for sensing ON failure is installed. When the ON-failure sensing means senses the ON failure, a water amount servo 4 that is an inflow water amount variable device is actuated to reduce water amount in a water passage pipe 2. |
