Carrier 38QUS012D8S Service Manual page 138

2.4.4.17. J5 Malfunction
Malfunction conditions
Possible causes
J5 displayed
J5 displayed
High pressure protection
High pressure protection
Are the high pressure
Are the high pressure
switch and main control
switch and main control
boar wired correctly?
boar wired correctly?
Yes
Is the high
Is the high
pressure protector
pressure protector
broken?
broken?
Method:
Disconnect the plug.
Method:
Disconnect the plug.
Measure the resistance of
Measure the resistance of
high pressure protector, if
high pressure protector, if
the protector is normal the
the protector is normal the
value is o, Does a problem
value is o, Does a problem
still exist?
still exist?
Yes
Is the outdoor ambient
Is the outdoor ambient
temperature is higher than
temperature is higher than
50℃?
50℃?
No
Check if the outdoor unit
Check if the outdoor unit
ventilation is good
ventilation is good
Yes
Is the outdoor fan running
Is the outdoor fan running
properly?
properly?
Yes
Is the heat exchanger dirty?
Is the heat exchanger dirty?
No
Replace outdoor main
Replace outdoor main
board. Is the problem
board. Is the problem
resolved?
resolved?
No
Check whether the refrigerant
Check whether the refrigerant
system is functioning properly
system is functioning properly
Electrical Control System
If the sampling voltage is not 5V, the LED displays a failure
code.
● Wiring mistakes
Faulty overload protector
●
● System blockages
●
Faulty outdoor PCB
Connect high pressure
Connect high pressure
No switch and mian control
switch and mian control
board
board
the
the
No
Replace high pressure protector
Replace high pressure protector
Yes Stop the unit
Stop the unit
Ensure that the outdoor unit
Ensure that the outdoor unit
NO
ventilation is functioning properly
ventilation is functioning properly
please refer to the solution of fan
please refer to the solution of fan
speed has been out of control
speed has been out of control
No
malfunction . Find out the cause and
malfunction . Find out the cause and
have it solved.
have it solved.
Yes
Clean the heat exchanger
Clean the heat exchanger
Troubleshooting
136