Troubleshooting - Mitsubishi Electric MS09NW Service Manual

11

TROUBLESHOOTING

MS09NW MS12NN MS15NN MS17NN MS09NW2 MS12NN2 MS15NN2 MS17NN2
11-1. Cautions on troubleshooting
1. Before troubleshooting, check the followings:
1) Check the power supply voltage.
2) Check the indoor/outdoor connecting wire for mis-wiring.
2. Take care the followings during servicing.
1) Before servicing the air conditioner, be sure to first turn off the remote controller to stop the main 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 how many times abnormality indication is flashing on and off 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 on page 45 and the check table on page 45.
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, replace the batteries in the following order.
The remote controller has a RESET button. After installing new batteries, press the RESET button with tip end of ball
point pen or the like, and then use the remote controller.
<MS09NW, MS12/15/17NN>
Lead wiring
RESET button
Housing point
<MS09NW2, MS12/15/17NN2>
44
RESET button