Carrier 42QHP09E8S Service Manual page 75

5.10 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:
• Power supply issues
• System leakage or blockage
• Faulty PCB
Troubleshooting and repair:
Check the connections and wires.
is the voltage between P and N is around
DC 310V, 340V or 380V? When start up
the unit, is it in 220V~400V?
Check the power supply.
Is it in working order?
YES
Are they in working order?
YES
Power on and measure the
voltage between P and N.
While the unit is in standby,
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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