MITSUBISHI ELECTRIC MUZ-GB50VA - Manual (Page 15)

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10 TROUBLESHOOTING
3. Troubleshooting procedure
1) First, check if the OPERATION INDICATOR lamp on the indoor unit is flashing on and off to indicate an abnormality.
To make sure, check how many times the abnormality indication is flashing on and off before starting service work.
2) Before servicing check that the connector and terminal are connected properly.
3) If the electronic control P.C. board is supposed to be defective, check the copper foil pattern for disconnection and
the components for bursting and discoloration.
4) When troubleshooting, refer to 10-2., 10-3. and 10-4.
10-1. Cautions on troubleshooting
1. Before troubleshooting, check the following:
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the following during servicing.
1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and then after
confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
2) Be sure to turn OFF the power supply before removing the front panel, the cabinet, the top panel, and the electronic
control P.C. board.
3) When removing the electrical parts, be careful to the residual voltage of smoothing capacitor.
4) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
5) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
Housing point Lead wiring
MUZ-GB50VA
9-3. Relation between main sensor and actuator
<MUZ-GB50>
Discharge temperature thermistor
Indoor pipe temperature thermistor
Defrost thermistor
Fin temperature thermistor
Outdoor heat exchanger temperature
Ambient temperature thermistor
Purpose
Protection
Defrosting Protection
Defrosting
Protection
Protection
Protection
Compressor LEV
Outdoor
fan motor R.V. coil
Sensor
Actuator
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