28
2. IPM prot ec t ion (H5), de- synchroniz i ng mal function (H 7) , over-cur rent of compressor phase current (P5) (AP1 below mea ns control board of
the outdoor unit).
Main detection points:
S Is voltage input within the normal range?
S Is the control board AP1 connected with the compressor
comp?
S Are the connections tight?
S Is the connection sequence correct?
S Heat exchange of unit is blocked (heat exchanger is dirty).
S Is the system pressure too high?
S Is the refrigerant charging amount correct?
S Is the coil resistance of compressor normal?
Malfunction diagnosis process:
 
N
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 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 
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
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
Fig. 31 – Troubleshooting