Carrier 38MGRBQ18B-3 - DIAGNOSIS AND SOLUTION (CONT); Current Overload and Compressor Speed Malfunctions

38MGRBQ: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
64
DIAGNOSIS AND SOLUTION (CONT)
P3/PC 08 (Current overload protection)/ PC 44(Outdoor unit zero speed protection)/PC 46(Compressor speed is out
of control)/PC 49 (Compressor overcurrent failure) diagnosis and solution
Troubleshooting
ERROR CODE
P3/PC 08/PC 44/PC 46/PC 49
MALFUNCTION DECISION
CONDITIONS
If the outdoor current exceeds the current limit value, the LED displays the failure.
SUPPOSED CAUSES
Wiring mistake
Faulty overload protector
System block
Faulty Outdoor PCB
Current protection of compressor
Yes
Replace the electric control box
Check whether the
refrigerant system
is ok
Judge 2: Check whether the
outdoor ambient temperature
is higher than 50ć
No
Stop the unit
Yes
Judge 3: Check whether the
outdoor unit has poor ventilation
No
Ensure the outdoor unit ventilates wellYes
Judge 5: The refrigerant pipe is
blocked
No
Yes
Judge 4: Check whether the
heat exchanger is dirty
No
Clean the heat exchangerYes
Yes
Replace outdoor main
board, and check whether the
system can run normally
No
Yes
Problem solved
Replace outdoor main boardNo
Judge 1: Check if the input current
of the power supply wire is greater
than 15A (18K). For 27K and High Heat
18K, it is 18.5A. For 36K and High Heat
27K, it is 22.5A. For 48K and
High Heat 36K, it is 28A.
Evacuate the refrigerant, then use the high
pressure nitrogen or refrigerant to blow pipe,
vacuumize and charge the refrigerant again