Carrier 38MBRQ48A-3 - Low Pressure Protection (J6;P6) Malfunction; Troubleshooting J6;P6 Malfunction

38MBR: Service Manual
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J6 Malfunction
Troubleshooting
Error Code J6/P6
Malfunction decision conditions If the sampling voltage is not 5V, the LED displays a failure code.
Supposed Causes
• Faulty wiring
• Faulty overload protector
• System blockage
• Faulty outdoor PCB
J6 displayed
Low pressure protecƟon
Are the low pressure
switch and main control
board wired correctly?
Yes
Connect the low pressure
protector and main control
board.
No
Is the low pressure
protector broken?
Yes
Method: Disconnect the plug.
Measure the low pressure
protector resistance. If the
protector is normal, the value is
0. Does the problem sƟůů exist?
Replace the high pressure
protector.
No
Is the outdoor ambient
temperature too low?
Stop the unit.
Yes
Is the core value of the
high pressure valve
opened fully?
No
Open the valve core of the
high pressure valve.
No
Is the indoor fan
running properly in the
COOLING mode?
Yes
Refer to the Fan Speed Out of
Control MalfuncƟon soluƟon.
IdenƟfy the cause and resolve.
No
Yes
No
Check whether the refrigerant
system is funcƟoning properly.
Replace the
outdoor main
board.
Is the problem
resolved?
When the refrigerant level is not
suĸcient, does the system
funcƟon properly aŌer more
refrigerant is added?
No