Defrost Control - Gree GWC09KF-D3DNA5A Service Manual

During cooling operation, the signals being sent from the indoor unit allow the operating frequency limitation and then prevent freezing
of the indoor heat exchanger. (The signal from the indoor unit must be divided into the zones as the followings.)
Detail
Conditions for Start Controlling
Judge the controlling start with the indoor heat exchanger temperature after 2 sec from operation start.
Control in Each Zone
Heating Peak-cut Control
Outline
Heat Pump Only
During heating operation, the signals being sent from the indoor unit allow the operating frequency limitation and prevent abnormal
high pressure. (The signal from the indoor unit must be divided as follows.)
Detail
Conditions for Start Controlling
Judge the controlling start with the indoor heat exchanger temperature after 2 sec. from operation start.
Control in Each Zone
The heat exchange intermediate temperature of indoor unit controls the following.

Defrost Control

Outline
Heat Pump Only
Defrosting is carried out by the cooling cycle (reverse cycle). The defrosting time or outdoor heat exchanger temperature must be more
than its fixed value when finishing.
Detail
Conditions for Starting Defrost
The starting conditions must be made with the outdoor air temperature and heat exchanger temperature. Under the conditions that the
system is in heating operation, 6 minutes after the compressor is started and more than 44 minutes of accumulated time pass since
the start of the operation or ending the defrosting.
Conditions for Canceling Defrost
The judgment must be made with heat exchanger temperature. (39°F~72°F)
34
Heat exchanger
thermistor temperature
A
B
C
D
E
Heat exchanger
thermistor temperature
Return/Reset zone
Up zone
Keep zone
Drooping zone
Stop zone
Stop zone
Drooping zone
Keep zone
Up zone
Reset zone
Function and Control