Mitsubishi Electric MU-GE50VB, Service Manual

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18
Part name Check method and criterion Figure
Defrost
thermistor
(RT61)
MUH-GE50VB
Measure the resistance with a tester.
(Part temperature –10°C ~ 40°C)
Refer to 11-4. “Test point diagram and voltage”, “Outdoor deicer
P.C. board”, for the chart of thermistor.
Compressor
(MC)
INNER
PROTECTOR
150 ± 5°C OPEN
90 ± 10°C CLOSE
Measure the resistance between the terminals with a tester.
(Coil wiring temperature –10°C ~ 40°C)
Terminal Normal
C-R 1.59 ~ 1.95
C-S 2.65 ~ 3.24
Outdoor fan
motor
(MF)
INNER FUSE
152°C
CUT OFF
Measure the resistance between the terminals with a tester.
(Coil wiring temperature –10°C ~ 40°C)
Color of
lear wire
Normal
MU-GE50VB MUH-GE50VB
WHT-BLK 190 ~ 233 190 ~ 233
BLK-RED 271 ~ 332 271 ~ 332
P
R
C
S
RED
BLK
WHT
MAIN AUX.
P INNER PROTECTOR
WHT RED
BLK
MAIN
AUX.
FUSE
Check of outdoor unit
Compressor and/or outdoor fan motor does not operate.
Yes
Compressor
doesn't operate.
Yes Yes
Is there 230 V AC between 3 on the
compressor contactor (52C) and
on the outdoor terminal block (TB1)?
Operate the unit in COOL or HEAT mode by pressing the EMERGENCY OPERATION switch.
3-minute time delay works.
Test run operation operates for 30 minutes.
Outdoor fan motor
doesn't operate.
No
Rectify the indoor and
outdoor connecting wire.
Rectify the connecting wire.
Check the compressor and compressor
capacitor, and rectify the connecting wire.
Start
Yes
Is there 230 V AC between 4 on the
compressor contactor (52C) and
TAB20 on the deicer P.C. board?
Is there 230 V AC between
on the outdoor terminal block (TB1)?
Replace the
deicer P.C. board.
Replace the
deicer P.C.
board.
No
No
Yes
Yes
No
Check the outdoor fan motor
and rectify the connecting
wire.
Is there 230 V AC between 4 on the
compressor contactor (52C) and
TAB20 on the deicer P.C. board?
Replace the
deicer P.C. board.
No
Yes
Rectify the indoor and
outdoor connecting wire.
Rectify the connecting wire.
Is there 230 V AC between on
the outdoor terminal block (TB1)?
No
No
+ –
Is there 5 V DC between J205 –J101 on
the deicer P.C. board?
+ – Is there 5 V DC between J205 –J101 on
the deicer P.C. board?
MU-GE50VB MUH-GE50VB
11-2. TROUBLE CRITERION OF MAIN PARTS
11-3. TROUBLESHOOTING FLOW <MUH-GE50VB>