Service manual

11-7
TROUBLESHOOTING
SM SX DCI 1-A.3 GB
11.5.4 Checking the Compressor.
The compressor is brushless permanence magnetic DC motor. Three coil resistance is same.
Check the resistance between three poles. The normal value should be below 0.5 ohm
(TBD).
11.5.5 Checking the Reverse Valve (RV).
Running in heating mode, check the voltage between two pins of reverse valve connector,
normal voltage is 220VAC.
11.5.6 Checking the electrical expansion valve (EEV).
The EEV has two parts, drive part and valve. The drive part is a step motor; it is ringed on the
valve. Check the drive voltage (12VDC). When Outdoor unit is power on, EEV shall run and
have click and vibration.
11.6 Precaution, Advise and Notice Items
11.6.1 High voltage in Outdoor unit controller.
Whole controller, including the wires that are connected to the Outdoor unit controller may
have the potential hazard voltage when power is on. Touching the Outdoor unit controller may
cause an electrical shock.
Advise: Don’t touch the naked lead wire and don’t insert finger, conductor or anything else into
the controller when power is on.
11.6.2 Charged Capacitors
Three large-capacity electrolytic capacitors are used in the Outdoor unit controller. Therefore,
charging voltage (380VDC) remains after power down. Discharging takes about four minutes
after power is off. Touching the Outdoor unit controller before discharging may cause an
electrical shock.
11.6.3 Additional advises
• When disassemble the controller or the front panel, turn off the power supply.
• When connecting or disconnecting the connectors on the PCB, hold the whole housing,
don’t pull the wire.
• There are sharp fringes and sting on shell. Use gloves when disassemble the A/C units.
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CONTENT