Low Pressure Protection Error (P2) - Carrier 38MGR Series Service Manual

DIAGNOSIS AND SOLUTION (CONT)

Low pressure protection error (P2)

ERROR CODE
MALFUNCTION DECISION
CONDITIONS
SUPPOSED CAUSES
Troubleshooting
56
P2
If the sampling voltage is not 5V, the LED displays the failure.
• Wiring mistake
• Over load protector faulty
• System block
• Outdoor PCB faulty
Low Pressure Protection
Is the wiring between the low
pressure protector and main
control board well connected?
Yes
Is the low pressure
protector broken?
Method: Disconnect the plug.
Measure the resistance of the
low pressure protector.
If the protector is normal,
the value is 0.
Yes
Check if the outdoor ambient
temperature is too low.
No
Check if the high pressure
valve core is opened.
Yes
Check if the outdoor
fan runs properly in the
cooling mode.
Yes
Replace the outdoor
main board.
No
Refrigerant is low.
Add more refrigerant.
No
Check if the
refrigerant system
is operating as designed.
Specifications subject to change without notice.
No
Connect the main board correctly.
No
Replace the low pressure protector.
Yes
Stop the unit.
Fully open the
No
high pressure valve.
Please refer to the Out of Control
Fan Speed solution.
No
Identify the cause and
.
resolve the issue.
38MGR-04SM