MITSUBISHI ELECTRIC MSZ-FD25VAS - Manual (Page 20)

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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) When the P.C. board seems 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.
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.
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.
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 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 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 housing of the connector. DO NOT pull the lead wires.
Housing point Lead wiring
MSZ-FD25VA MSZ-FD25VAS MSZ-FD35VA MSZ-FD35VAS
RESET button
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
2 Press RESET button with tip end of ball point pen
or the like, and then use the remote controller. 1 Remove the front lid and insert batteries.
Then reattach the front lid.
Lock
2
1
If horizontal vane is not installed correctly, all of the operation indicator lamps will blink.
In this case, install the horizontal vane correctly by following the procedures
1 to 2 .
NOTE : Before installation of the horizontal vane, turn OFF the power supply.
5. How to install the horizontal vane
In procedure 2 2 lock the
stoppers until they click
into place.
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