Carrier 38QUS012D8S Service Manual page 129

2.4.4.7. F4 Malfunction
Malfunction conditions
Possible causes
F4- Display
F4- Display
Outdoor EEPROM malfunction
Outdoor EEPROM malfunction
Power off, then restart the
Power off, then restart the
unit 2 minutes later. Does a
unit 2 minutes later. Does a
problem still exist?
problem still exist?
Yes
Replace the outdoor main PCB
Replace the outdoor main PCB
EEPROM: An electrically erasable programmable read-only memory whose contents can be erased and
reprogrammed using a pulsed voltage.
2.4.4.8. F5 Malfunction
The same as E3 in indoor unit.
Electrical Control System
Main PCB chip does not receive feedback from EEPROM chip
● Installation mistakes
● Faulty PCB
Troubleshooting
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