DEFROSTING CONTROL METHOD FOR AIR-COOLED HEAT PUMP TYPE HOT WATER FEEDER

摘要

PURPOSE:To prevent wasteful defrosting operation by completing the defrosting operation on condition that temperature on the surface of a pipe of an air side heat exchanger has rise up to the level of a predetermined temperature, without waiting for the increase of a high-pressure side pressure and the lapse of a predetermined period, in the case where the high-pressure side pressure does not increase even if frost formed on the air side heat exchanger is thawed. CONSTITUTION:When a contact 15a2 is closed, a coil 13 of a timer for counting a defrosting operation time is excited, and the timer counts the defrosting operation time. During the period of this operation time, if a temperature on the surface of a pipe for an air side heat exchanger rises to close the contact point 11 of a thermostat or if a high-pressure side pressure increases to close the contact 12 of a high-pressure switch, a coil 18 of an auxiliary relay for defrosting completion is excited to open its contact 18b, and then a defrosting instruction is cancelled. Further, even if a temperature on the surface of the pipe and a high-pressure side pressure do not increase, a contact 13a is closed when the defrosting operation time reaches a predetermined period of time set to the timer 13, whereby the defrosting instruction is cancelled in a similar manner to return to a hot water feed operation.