Friedrich FPHMR18A3A Service Manual page 48

Control Mode
Fan Only Mode
(1) Outdoor fan and compressor stop.
(2) Temperature setting function is disabled, and no setting temperature is displayed.
(3) Indoor fan can be set to high/medium/low, but can not be set to auto.
Cooling Mode
Indoor fan logic:
Runs all the time and the speed can be selected as
high, (medium), low and auto.
The auto fan:
T1 is indoor room temperature. Ts is setting temperature.
Compressor:
Once the compressor starts up, it will follow the below rules:
When indoor room temp.T1 is lower than Ts, the compressor and outdoor fan will
shut off. When T1 is higher than Ts+1, the compressor and outdoor fan will start up.
Outdoor fan:
Once the outdoor fan starts up, it will operate as follows:
Single outdoor fan: The fan will start with irregular speeds for about 10 seconds, then will
be throttled depending on outdoor coil and ambient air temperature.
Double outdoor fan: The upper and lower fan start with irregular speeds for about 10
seconds, then will throttled depending on outdoor coil and ambient air temperature.
The lower fan will be 30rpm-60rpm less than the upper fan.
48
OPERATION
High
Medium
Low
0
-1
2
4
T 1- Ts