Mitsubishi Electric MSZ-A09NA Series Service Manual page 12

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 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 8-2., 8-3. and 8-4.
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.
Insert the negative pole of the
batteries first. Check if the polarity
of the batteries is correct.
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 microprocessor control when batteries are replaced.
This function is equipped to prevent the microprocessor control from malfunctioning due to the voltage drop caused
by the battery replacement.
INFORMATION FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT: MXZ series
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
• When you try to operate two or more indoor units with one outdoor unit simultaneously, one for the cooling and the
other for heating, the operation mode of the indoor unit that operates earlier is selected. Other indoor units cannot
operate, and operation indicator lamp flashes as shown in the figure below. In this case, please set all the indoor
units to the same operation mode.
• When indoor unit starts the operation while the defrosting of outdoor unit is being done, it takes a few minutes (max.
10 minutes) to blow out the warm air.
• In the heating operation, though indoor unit that does not operate may get warm or the sound of refrigerant flowing
may be heard, they are not malfunction. The reason is that the refrigerant continuously flows into it.
OPERATION INDICATOR
12
Press RESET button with tip end of ball point pen
or the like, and then use the remote controller.
RESET button
Lighted
Blinking
Not lighted