Troubleshooting - Mitsubishi Electric MS-18NV Service Manual

10

TROUBLESHOOTING

MS-18NV -
E4
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 first turn off the remote controller to stop the unit, and then after
confirming the horizontal vane is closed, turn off the breaker and / or disconnect the power plug.
2) When removing the electronic control P.C. board, hold the edge of the board with care NOT to apply stress on the
components.
3) When connecting or disconnecting the connectors, hold the housing of the connector. DO NOT pull the lead wires.
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 the abnormality indication for 2 or 3 times before starting service work.
2) 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.
3) When troubleshooting, refer to the flow chart and the check table on page 19.
4. How to replace batteries
Weak batteries may cause the remote controller malfunction.
In this case, the remote controller can not be repaired only by the battery replacement. To operate the remote
controller normally, discharge the remote controller in the following order.
This remote controller has the RESET button. After refilling new batteries, press the RESET button with tip end of ball
point pen or the like, and then use the remote controller.
18
RESET button