Troubleshooting - Mitsubishi Electric MCFH-A12WV Service Manual

9

TROUBLESHOOTING

MCFH-A12WV -
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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 mis-wiring.
2. Take care the following during service.
(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 has completely closed, turn off the breaker.
(2) Be sure to unplug the power cord before removing the air inlet grille, the front panel, the cabinet, the top panel and
the electronic control P.C. boards.
(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 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 the 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 and the check table on page 12 and 13.
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.
1 Remove the front lid and insert batteries.
Then reattach the front lid.
NOTE : If the RESET button is not pressed, the remote controller may not operate correctly.
INFORMATION FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT : MXZ-A18WV-
Multi system air conditioner can connect two or more indoor units with one outdoor unit.
•Unit won't 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 flashes 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 that
will start the operation later cannot operate, indicating as shown in the figure below. In this case, please set all the
indoor units to the same operation mode.
•When indoor units 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.
MCFH-A18WV -
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Insert the negative pole
of the batteries first.
Check if the polarity of
the batteries are correct.
MXZ-A26WV-
E1 E1
MCFH-A24WV -
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2 Press the RESET button with tip end of ball point
pen or the like, and then use the remote controller.
RESET button
MXZ-A32WV-
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Operation Indicator
11
lighted
flashing