When Operation Indicator Lamp Flashes 6-Time; Thermistors In The Outdoor Unit Are Abnormal; Cool Air Does Not Blow Out Although Indoor Unit Is Operating - Mitsubishi Electric MSC-A07WV Service Manual

When OPERATION INDICATOR lamp flashes 6-time.
Thermistors in the outdoor unit are abnormal.
H H Check of outdoor thermistor
Start
Defrost thermistor (RT61)
Measure
resistance
Turn OFF the
between CN 661
power supply.
1 and 2.

Cool air does not blow out although indoor unit is operating.

I I Check of indoor/outdoor units' connection and outdoor unit
w In case of troubleshooting, be sure to operate indoor unit by emergency operation switch.
Start
Turn ON the power supply, and operate all the indoor
units at a time.
Do they perform the cooling operation?
Yes
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.
w1.
w1. MUX-A10WV MUX-A20WV MUX-A26WV
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 25, 27 or 28.
Indoor
Model
unit
A
MUX-A10WV
B
B
MUX-A20WV
C
A
B
MUX-A26WV
C
D
<MUH-A07/A09/A12WV>
Is the resistance of
thermistor normal?
No
Replace the
thermistor.
Turn OFF the power supply.
No
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 111.)
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.
Terminal Connector for
block solenoid coil control
TB2
21R1
21R
TB2
21R2
TB3
21R3-CN85
21RB-CN81
TB4
21R4-CN86
TB2
21R1-CN83
21RA-CN82
TB3
21R2-CN84
TB4
21R3-CN85
21RB-CN81
TB5
21R4-CN86
Reconnect CN661.
Turn ON the power
Yes
supply and press
the EMERGENCY
OPERATION
switch.
Defective contact of the connector is considered.
<MUX-A10/A19/A20/A25/A26WV>
No
Yes
No
MUX-A10WV
Is voltage 230V?
Yes
OK
MUX-A19/A20/A25/A26WV
118
Replace the deicer P.C.
board.
No
Does the unit operate
10 minutes or more?
Yes
OK
Replace the solenoid coil.
Check wiring of outdoor
unit and relay. (Refer to page 27.)
Replace the outdoor
control P.C. board.