Start-Up Failure (Lc) (Ap1 Below Means Control Board Of Outdoor Unit) - Carrier 38GRQB12-3 Service Manual

4. Start- up failure (LC) (AP1 below means control board of the outdoor unit.
Main detection points:
S Is the compressor wiring correct?
S Is the compressor stop time sufficient?
S Is the compressor damaged?
S Is the unit overcharged?
Turn on the unit
Does the unit turn on
within 3min?
Yes
Is the compressor
wired correctly?
Yes
Is the unit over charged?
Yes
Charge the refrigerant
according to unit
nameplate
Does the unit
start up normally?
No
Replace outdoor
mainboard AP1
Is the malfunction
eliminated?
No
Replace the
compressor
End
Fig. 33 – Troubleshooting
Is the charge in the system correct and
have you opened both liquid and
No
suction valves? Does the unit start?
Check the connection
of outdoor mainboard AP1 and
compressor, and then
No
connect it according to wiring
diagram
Does the unit
start up normally?
No
Yes
Yes
30