
5 Control system
Standard control functions
SMGB0091 rev.2 - 11/2015
89
5
5.4 Standard control functions
5.4.1 Freezing protection during cooling process or dry operation
Anti-freeze control depends on 2 conditions:
CONDITION 1:
CONDITION 2:
No
Power supply
Compressor and indoor
unit fans OFF
Is compressor
operated for more
than *30 min.?
Cooling or dry
operation
Gas or liquid pipe
surface temperature of
indoor heat exchanger
Is it continuous for
more than 3 min.?
Yes
*) The check interval differs
depending on the conditions
Higher than 0 ºC
No
Lower than 0 ºC
Yes
Gas or liquid pipe
surface temperature of
indoor heat exchanger
Lower than
11ºC
Higher than 11 ºC
Lower than
2 ºC
Higher than 2 ºC
Liquid pipe
temperature of indoor
heat exchanger
Power supply
Compressor and indoor
unit fans OFF
Outdoor ambient
temperature
Cooling or dry
operation
Gas or liquid pipe
surface temperature of
indoor heat exchanger
Is it continuous for
more than 60 min.?
Higher than 2 ºC
Higher than 25 ºC
Lower than 25 ºC
No
Lower than 2 ºC
Yes
Gas or liquid pipe
surface temperature of
indoor heat exchanger
Lower than
11ºC
Higher than 11 ºC
Lower than
2 ºC
Higher than 2 ºC
Liquid pipe
temperature of indoor
heat exchanger