Troubleshooting - Mitsubishi Electric MLZ-KP09NA Service Manual

9

TROUBLESHOOTING

MLZ-KP09NA MLZ-KP12NA MLZ-KP18NA
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 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
electronic control P.C. board.
3) When removing the electronic control 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 blinking ON and OFF to indicate an abnormality.
To make sure, check how many times the OPERATIONAL INDICATOR lamp is blinking 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) 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.
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 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.
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.
•Unit will not operate in case the total capacity of indoor units exceeds the capacity of outdoor units.
Do not connect indoor units beyond the outdoor unit capacity.
Operation indicator lamp blinks as shown in the figure below.
•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. The other indoor units cannot
operate and indicate as shown in the figure below. In this case, please set all the indoor units to the same operation mode.
OPERATION INDICATOR
•When indoor units start operation while the defrosting of outdoor unit is being done, it takes a few minutes (maximum
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.
OBH802A
<Incorrect>
Lead wiring
Connector housing
Lit
Blinking
Not lit
21
sandium.com
<Correct>
Press RESET button with a fine-tipped object, and
then use the remote controller.
RESET button