Haier AU55NFIAIA Service Manual page 64

Commercial Air Conditioner
Model: AU55NFIAIA
We have changed the program of PCB. We call it as shut-off single fan motor control. In low
temperature cooling mode, we can realize low pressure of compressor in a high range by
start/stop fan motor, but the compressor pressure will change greatly in the two states of
start/stop fan motor, so we design the shut-off single fan motor function to reduce the pressure
difference.
The following is how to control single fan motor operation:
Control the neutral wire of FAN1 with a single probe relay, it is open when fan motor is on. In
below conditions it will shut off to realize single fan motor control.
P25 PMV2---B2 single fan motor control
In cooling mode: after compressor runs for 3 minutes, it will adjust, if Tc <25 degree, the relay
cuts off, if not,(Tc>27degree,there is 2 degree difference),fan motor works while relay is close.
In heating mode: after compressor runs for 3 minutes, it will adjust, if Tc >15 degree, the relay
cuts off, if not,(Tc<13degree,there is 2 degree difference),fan motor works while relay is close.
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