PURPOSE: A defrosting control circuit wherein the defrosting is started after a predetermined lapse of time through the function of a defrosting thermostat and a defrosting time-limit relay, comprising a high-pressure pressure switch which finish the defrosting when the pressure rises during the limit time and a time-limit relay which finish the defrosting when the pressure does not rise during the limit time.
CONSTITUTION: With a predetermined lapse of time after heating is started, a decider DS detects the frosting based on the temperature drop in an air flow-side heat exchanger, a contact is opened, a blower switch 2 is cut off, and a blower is stopped. A four-way selector valve 5 is changed over, defrosting is started, and a time-limit relay 4 is fed with power for continuing the defrosting. When the decier DS has returned and the water temperature is high, the pressure rises, a high- pressure pressure switch HP2 operates, power is fed to the switch 2 to drive the blower, the valve 5 is changed over, defrosting is finished, and heating is started. When the water temperature is low and a predetermined time has passed without rise in the pressure, the relay 4 operates, the switch 2 is fed with power to drive the blower, the valve 5 is changed over, defrosting is finished, and heating is started.
HORIUCHI ISAMU
TERADA HIROHARU
KITANI FUMIHIKO
YOSHIOKA KAZUO
KOJIMA TERUAKI
KAWAKAMI TAKASHI
| JP49150953B | ||||
| JP50049756B |