Carrier 619FB Service Manual page 28

2. IPM protection (H5), de- -synchronizing malfunction (H7), over- -current of compressor phase current (P5) (AP1 below means 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?
Malfunction diagnosis process:
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)
Yes
The compressor
is connected
with mainboard
AP1?
Yes
Heat exchanger is
blocked with dirt?
No
Check if system pressure
is too high?
No
Replace outdoor
mainboard AP1
Repair power supply
No
No
Adjust it properly
according to wiring
No
diagram 5.1
No
Clean the heat exchanger
Yes
to improve its performance
No
Adjust refrigerant
Yes
charging amount
Does the unit
work normally
N
Replace compressor
Fig. 31 – Troubleshooting
S Heat exchange of unit is blocked (heat exchanger is dirty).
S Is the system pressure too high?
Is the refrigerant charging amount correct?
S
Is the coil resistance of compressor normal?
S
Restart the unit
Restart the unit
Restart the unit
Restart the unit
Yes
28
The unit starts
Yes
operation again
The unit starts
Yes
operation again
The unit starts
Yes
operation again
The unit starts
Yes
operation again
End