Westinghouse WHZ09WMA21S Service Manual page 31

Trouble Diagnosis of Compressor
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.
Trouble Diagnosis of Electric Filter Board
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.
Trouble Diagnosis of Electric Communication
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.
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