Troubleshooting - Mitsubishi Electric MSZ-AY25VG-ET1 Service Manual

10

TROUBLESHOOTING

MSZ-AY25VG MSZ-AY35VG
MSZ-AY25VGK MSZ-AY35VGK MSZ-AY42VGK MSZ-AY50VGK
MSZ-AY25VGKP MSZ-AY35VGKP MSZ-AY42VGKP MSZ-AY50VGKP
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 miswiring.
2. Take care of the following during servicing
1) Before servicing the air conditioner, be sure to turn OFF the main unit first with the remote controller, and after confirm-
ing 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 P.C. board.
3) When removing the P.C. board, hold the edge of the board with care NOT to apply stress on the components.
4) When connecting or disconnecting the connectors, hold the connector housing. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) Check if the OPERATION INDICATOR lamp on the indoor unit is blinking ON and OFF to indicate an abnormality.
To make sure, check how many times the OPERATION INDICATOR lamp is blinking ON and OFF before starting ser-
vice work.
2) Before servicing, verify that all connectors and terminals are connected properly.
3) When the electronic control P.C. board seems to be defective, check for disconnection of the copper foil pattern and
burnt or discolored components.
4) When troubleshooting, refer to 10-2, 10-3 and 10-4.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, replace the batteries to operate the remote controller normally.
Remove the front lid and insert batteries.
Then reattach the front lid.
NOTE: 1. If RESET button is not pressed, the remote controller may not operate correctly.
2. This remote controller has a circuit to automatically reset the microcomputer when batteries are replaced.
This function is equipped to prevent the microcomputer from malfunctioning due to the voltage drop caused by the
battery replacement.
3. Do not use the leaking batteries.
OBH932
MSZ-AY42VG
<Incorrect>
Lead wiring
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
MSZ-AY50VG
<Correct>
Connector housing
Press RESET button with a fine-tipped object, and
then use the remote controller.
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