50
Installation and Maintenance
Service Manual
5. IPM protection(H5), desynchronizing malfunction(H7), overcurrent of compressor phase current (P5) (AP1 below
means control board of outdoor unit)
Main detection points:
● Is voltage input within the normal range
● If the control board AP1 is well connected with compressor COMP? If they are loosened? If the connection sequence is
correct?
● Heat exchange of unit is not good (heat exchanger is dirty and unit radiating environment is bad);
● If the system pressure is too high?
● If the refrigerant charging amount is appropriate?
● If coil resistance of compressor is normal? Is compressor coil insulating to copper pipe well?
● If the work load of unit is heavy? If radiating of unit is good?
Malfunction diagnosis process:
N
N
Y
N
Y
Y
Y
N
N
N
N
N
Y
Y
Y
Y
Y
H5, H7 or P5 is
displayed after
turning on the unit
Measure if the voltage
input is within 180~265V
with AC voltmeter
(see fig 30)
The compressor
is well connected
with mainboard
AP1?
Heat exchanger is
blocked with dirt?
Clean the heat exchanger
to improve its performance
Restart the unit
Restart the unit
Restart the unit
Restart the unit
The unit starts
operation again
The unit starts
operation again
The unit starts
operation again
The unit starts
operation again
Repair power supply to make
the power voltage normal
Check if system pressure
is too high?
Adjust refrigerant
charging amount
Replace outdoor
mainboard AP1
Replace compressor
Does the unit
work normally
End
Adjust it properly
according to wiring
diagram 5.1
