Fedders R407C Service Manual page 65

7. Outdoor Coil De-icing in Heat Mode (applicable on Heat Pump Unit only)
The air-con controller heats up the outdoor coil to melt the ice formed at outdoor coil. To
achieve this, the compressor must be turned on, while the 4-way valve must be turned off.
During this period, the indoor fan must be switched off with exception condition as stated in
Note 1. otherwise it will fill the room with cool air and cause discomfort to the users.
Defrost thermistor below 40 C
Below –4 C
Compressor ON
4-way valve ON
Outdoor fan ON
Defrost counter
Indoor fan
OFF
OFF
60 sec.
OFF
ON
*Low
OFF
30 sec.
Max 8 min
Defrost Time Chart
60 sec.
60 sec.
Hot start
F18