| 摘要 |
PURPOSE:To prevent sticking of a hot water circulating pump for heater which tends to occur when not in use for a long time by a method wherein the pump is forcibly operated for a predetermined time at predetermined intervals of time while it is not used for heating or each time hot water supply is made. CONSTITUTION:In a gas-fired tap controlled hot water supply heater of two- heater and two-passage type comprising a built-in pump for circulating hot water for heating and a bypass circuit located in the heater, there is provided a power supply synchronous motor 4 adapted to cyclically drive the pump 8 when a microswitch 5 connected in series with the pump 8 is switched ON and OFF. In case the built-in pump 8 is forcibly operated, for example, twice a day and the power supply synchronous motor 4 is arranged to rotate one revolution in 24 hrs, a disk 4a with projection 4c formed at two places along the circumference thereof is used. By this arrangement, the disk 4a is rotated by the motor 4, and the pump 8 is forcibly rotated only when either of the projections 4c of the disk 4a is urged against a projection 5a of the microswitch 5. |
