Troubleshooting - Mitsubishi Electric Mr.Slim MU-A18ND-S1 Service Manual

(kgf/F[Gauge])(MPa[Gauge])
0.6
6.0
0.5
5.0
0.4
4.0
0.3
3.0
0.2
2.0
15 18 20
Ambient temperature (˚C)/Ambient humidity (%)
8

TROUBLESHOOTING

MU-A18ND MU-A24ND MU-A30ND
8-1. 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 turn off the main 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 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) Before servicing that the connector and terminal are connected properly.
3) 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 discolouration.
4) When troubleshooting, refer to 8-2.
MU-A30ND
25 30 32
50 60 70
15.0
14.0
13.0
12.0
11.0
10.0
9.0
35(:)
15 18 20
(%)
Ambient temperature (˚C)/Ambient humidity (%)
12
MU-A30ND
25 30 32
50 60 70
Housing point
Lead wiring
35(:)
(%)