Friedrich FPHFC36A3B Wi-Fi Service & Parts Manual page 66

Control Logic Description
Heating Mode
Indoor fan running rules:
The indoor unit fan will not run until the indoor unit heat heat exchanger reches a high enough temperature.
This is because the cold air prevention system is operating. After several minutes, the speed can be
selected to high, medium, low, or auto.
The auto fan:
T1 is indoor room temperature. Ts is setting temperature.
DC-Inverter outdoor unit ：
Outdoor fan running rules:
Once the outdoor fan start up, it will follow the below rules:
Single outdoor fan: First, it will run in an invariable speed f or a short time; Then it will regulate
the speed by the indoor-coil temperature.
Double outdoor fan: If it has two outdoor fans, the upper fan regulates the speed by the rul es,
and the downer fan speed lower than the upper fan speed for 30 r pm~60rpm.
66
OPERATION
High
Medium
Low
0
2
Ts-T1
4