Service manual

38
Check of defrost heater
M
Replace the inverter P.C. board.
Is there 230V AC between CN722 1 and 3 on the
power P.C. board? Refer to 11-7.2.
Yes
No
No problem of the
power P.C. board.
Is the voltage between CN726 2(+)-3(-) on the
power P.C. board 0V DC? Refer to 11-7.2.
Yes
No
Replace the power
P.C. board.
NOTE: In case both thermistors are more than the above
temperature, cool them with cold water etc...
In HEAT mode, for more than 5 minutes, let the ambient temperature thermistor continue to read 5: or less, and let the
defrost thermistor continue to read -1: or less.
3
2
1
230V AC
Check the following points before checking electric continuity.
1) Does the resistance of ambient temperature thermistor have the characteristics? Refer to 11-7.1.
2) Is the resistance of defrost heater normal? Refer to 11-5.
3) Does the heater protector remain conducted (not open)?
4) Are both ambient temperature thermistor and circuit of defrost heater securely connected to connectors?
26H
CN726
CN722
H
2 1
2 1
23
Outdoor base gets frozen.
<MUZ-FA25VAH MUZ-FA35VAH>
Check of inverter P.C. board
N
Outdoor fan motor does not operate, or stops immediately after starting up.
Yes
(10-time flash)
Check the LED indication on
the inverter P.C. board.
Does the LED flash 10-time?
No
Replace the inverter P.C. board.
CN931
CN932
Inverter P.C.board
(Solder side)
Check the corresponding parts
following LED indication.
(Refer to 11-4.)
Operate the outdoor unit by starting
EMERGENCY OPERATION.
Check the connection of the connectors
(CN931, CN932) of outdoor fan motor.
If the connection is poor, make it correct.
Check the outdoor fan motor.
Refer to11-6.I.
MUZ-FA25VA (Serial No : ~5002650T)
MUZ-FA25VAH(Serial No : ~5000400T)
MUZ-FA35VA (Serial No : ~5003000T)
MUZ-FA35VAH(Serial No : ~5000400T)
OB372D --2qxp 07.5.7 4:49 PM Page 38