19
Does compressor or
outdoor fan motor stop?
Replace the outdoor
control P.C. board.
Yes
OK
No
Replace the indoor
electoronic control
P.C. board.
Start
Turn OFF the power supply.
After 1 minute, turn ON
power supply again.
Is there 12V DC between
1
–
2
on the outdoor
terminal block (TB2 or TB3)?
No
Yes
B
B
Check of outdoor unit
Compressor and / or outdoor fan doesn’t stop.
C
C
Check of MU & MUX TYPE / MUH & MXZ TYPE SWITCH OVER
Start
Turn OFF the power supply (indoor / outdoor unit).
Set switch (SW2-
2
) on the indoor electronic
control P.C. board to MUX type.
w
1
Does the unit operate?
OK
Yes
No
Refer to the
"Instruction of
troubleshooting."
w
1 Set the switch (SW2-
2
) on indoor electronic control P.C. board to
MUX type, when the outdoor unit is MUX type.
If the setting is MUH or MXZ type, the unit does not work.
Refer to 12-6. MU & MUX TYPE / MUH& MXZ TYPE SWITCH OVER AND
AUTO RESTART FUNCTION on service manual OB307 REVISED EDITON-A.
When OPERATION INDICATOR lamp flashes 0.5-second intervals.
Outdoor unit doesn’t operate.
D
D
Check of indoor / outdoor units’ connection and outdoor unit
Cool air doesn’t blow out although indoor unit is operating.
Turn ON the power supply, and operate all the indoor
units at a time.
Yes
No
Operate the indoor unit one by one, and measure
the voltage between 1 and 2 of outdoor
terminal block for each indoor unit.
Match the signs of terminal block whose voltage is
12V DC and pipe of indoor/ outdoor units' connection.
w
1.
Do they perform the cooling operation?
Start
Indoor
unit
Model
Terminal
block
Connector for
solenoid coil control
B
C
TB3
TB4
21R3-CN85
21R4-CN86
21RB-CN81
w
1. If the pipe of indoor unit that does not operate is cooled
though the combination of pipe and connecting wire is correct,
check the solenoid coil. Refer to page 7.
Turn OFF the power supply.
Remove solenoid coil's connector that corresponds
to the indoor unit, which does not blow out cool air.
Then, measure the resistance of solenoid coil.
Do the resistance value normal?
(Refer to page 17.)
Yes
Reconnect solenoid coil's connector.
Then turn the main power on and operate the
indoor unit that does not blow out cool air.
Measure the voltage of solenoid coil's connector that
corresponds to the indoor unit, which is operated.
Replace the solenoid coil.
No
Is voltage 230V?
Yes
No
OK
MUX-A22WV
Replace the outdoor
control P.C. board.
w
In case of troubleshooting, be sure to operate indoor unit by emergency operation switch.
OB318--1.qxp 03.10.30 0:55 PM Page 19
