Carrier 40GRQB18H-3 - Diagnosis for Failure Start up Malfunction

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5. Diagnosis for failure start up malfunction (AP1 below is control board of outdoor unit)
Main detection points:
S Is the compressor wiring correct?
S Is the compressor stop time long enough?
S Is the compressor damaged?
S Is the refrigerant charged correctly?
Malfunction diagnosis process:
Energize the unit
and start it
If the compressor wire COMP(UVW) is
well connected and connection sequence
is correct
Replace control board AP1
Replace the
compressor
Is the malfunction
removed?
If the stop time of compressor
is more than 3min?
No
If the stop time is not enough and the
high and low pressure of system is not
balance , please start it after 3min
Improve the connection situation
of control board AP1 and
compressor COMP, connect it
with wiring diagram
No
Yes
N
Is the unit overcharged?
Yes
Does the unit start
up normally?
N
Charge the
refrigerant according
to service manual
Yes
Does the unit start
up normally?
No
Yes
End
No
No
Fig. 41 – Troubleshooting