Troubleshooting - Mitsubishi MSZ-EF09NAW-U1 Service Manual

Indoor unit
Table of Contents

Advertisement

9

TROUBLESHOOTING

MSZ-EF09NAW
MSZ-EF09NAB
MSZ-EF09NAS
9-1. 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 connector housing. DO NOT pull the lead wires.
3. Troubleshooting procedure
1) 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 OPERATION INDICATOR lamp is flashing ON and OFF before starting serv-
ice work.
2) Before servicing, check that the connector and terminal are connected properly.
3) When the electronic control 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 9-2, 9-3 and 9-4.
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.
OBH736
MSZ-EF12NAW
MSZ-EF12NAB
MSZ-EF12NAS
<Incorrect>
Lead wiring
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
MSZ-EF15NAW
MSZ-EF15NAB
MSZ-EF15NAS
<Correct>
Connector housing
Press RESET button with a thin instrument, and
then use the remote controller.
19
MSZ-EF18NAW
MSZ-EF18NAB
MSZ-EF18NAS
RESET button

Advertisement

Table of Contents
loading

Table of Contents