Carrier 38MGR Series - DIAGNOSIS AND SOLUTION: COMPRESSOR PROTECTION; Compressor Top Temperature Error (PO)

52 Specifications subject to change without notice. 38MGR-04SM
DIAGNOSIS AND SOLUTION (CONT)
Temperature protection of compressor top) error (PO)
Troubleshooting
ERROR CODE PO
MALFUNCTION DECISION
CONDITIONS
If the sampling voltage is not 5V, the LED displays the failure.
SUPPOSED CAUSES
• Wiring mistake
• Over load protector faulty
• System block
• Outdoor PCB faulty
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Temperature protection of the
compressor top.
Check the air ow system of the
indoor and outdoor units.
Clear up the air inlet and outlet or the indoor
and outdoor heat exchanger.
Power OFF, then restart
the unit minutes later.
Check whether the
compressor top temperature
is higher than 212 °F (100° C).
Check the refrigerant
volume charge.
Refrigerant system is blocked, for
ex. capillary or welded point of pipes.
Check the overload protector
of the wiring connection.
Correct the connection.
Measure the resistance
between the two OLP ports.
It is zero (0)?
Replace the OLP.
Replace the outdoor main PCB.
Recharge the correct
refrigerant volume.