Carrier 42QHC009DS Service Manual page 39

9.2.7 Over voltage or too low voltage protection diagnosis and solution(P1)
Error Code
Malfunction decision
conditions
Supposed causes
Trouble shooting:
Check the power supply
Yes
Check the connections and
wires
Yes
Check the voltage between P
and N
Yes
Check the reactor
Yes
Replace the reactor
P1
An abnormal voltage rise or drop is detected by checking the
specified voltage detection circuit.
Power supply problems.
●
System leakage or block
●
PCB faulty
●
No
No
No
No
Stop the unit
Correct the connections or
replace the wires.
Replace the IPM board
Replace outdoor main PCB
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