Carrier 40MPHA Service Manual page 29

DIAGNOSIS AND SOLUTION (CONT)
P1 (Over voltage or too low voltage protection diagnosis and solution)
Description: Abnormal increases or decreases in voltage are detected by checking the specified voltage detection circuit.
Recommended parts to prepare:
S
Power supply issues
S
System leakage or blockage
S
Faulty PCB
Troubleshooting and Repair:
Check the power supply
Check the connections and wires
Are they in working order ?
Power on and measure the
voltage between P and N
Wh ile the unit is i n standby,
is the voltage between P and N around
DC 310 V, 340 V or 380 V? On unit start up
is the unit in the 220 V ~
Is it in working order ?
YES
YES
400 V range?
YES
Check the reactor
Is it in working order ?
YES
Replace the reactor
NO
Turn off the unit.
Ensure proper connections or
NO
replace the wires
NO Replace the IPM board
NO Replace outdoor PCB
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