Compressor Fault Isolation; Indoor Fault Codes - Friedrich FPHMR18A3A Service Manual

TROUBLESHOOTING

Compressor Fault Isolation

Judging the connecting terminals of inverter compressor:
It is impossible to identify terminals U, V and W of inverter compressor with multi-meter. Just connect the terminals in the
same way as the original unit when replacing the compressor. A wrong connection will lead to reverse and loud noise of the
compressor.
Resistance of compressor coil:
Measure the resistance between any two terminals, which are about a few Ohms, three phases having the same resistance
Electric FIlter Board Fault Isolation
Visual examination: as the circuit is simple, the connection may be checked visually to see whether any loose or poor
connection.
Voltage test: the voltage at the input end shall be the same as the voltage at the output end.
Electrical Communication Fault ISOLATION
Step one: to determine whether the connecting cables and tether cables of indoor/outdoor units are correctly wired. If not,
change wiring order and test connection.
Step two: to determine whether there is loose connection.
Fasten the connection in the case of loose connection and then conduct verification.
Step three: measure the voltage between SI and N with multi-meter and see whether the voltage fluctuates between 0V and
24V. Please directly replace indoor and outdoor control boards if there are not voltage fluctuations

Indoor Fault Codes

76