How To Check Mis-Wiring - Mitsubishi Electric MSH-GA50VB Service Manual

When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit doesn't operate.

How to check mis-wiring

D
• Turn ON the power supply. (indoor/ outdoor unit)
• Press EMERGENCY OPERATION switch once.
Yes
Correct them.
1. Turn OFF the power supply (indoor/ outdoor unit) and disconnect indoor and outdoor
connecting wire on indoor side.
2. Short-circuit terminal block N-3 by lead wire.
3. Turn ON the power supply (indoor unit) and press EMERGENCY OPERATION switch once.
Refer to outdoor unit service manual.
Start
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
on OPERATION INDICATOR
lamp on indoor unit.w
Is this mis-wiring, poor contact,
or wire disconnection?
No
Is there 20V DC between both ends of
R132 on the indoor electronic control P.C.
board ?
( By tester, the stylus is between 0 ~ 20V. )
Yes
• Turn OFF the power supply. (indoor unit)
• Connect indoor/ outdoor connecting
wire.
Turn ON the power supply. (outdoor unit)
Is there 230V AC between L-N
on the outdoor terminal block?
Yes
Is there 5V DC between J205 + -J101 -
(MUH-GA50VB)/ J101 + -J401 - (MUH- GA60
/GA80VB) on the deicer P.C. board?
Yes
During EMERGENCY OPERATION, is there
10V DC between both ends of R601 on the
deicer P.C. board?
(By tester, the stylus is between 5 ~10V.)
Yes
Replace the deicer P.C. board.
w Short circuit of JPG and JPS on the indoor electronic control
P.C. board enables self -check to be displayed in 3 seconds.
No
Replace the indoor electronic
control P.C. board.
No
Check the outdoor power supply
and connection of wiring.
No
Replace the deicer P.C. board.
Make the wiring between CN730
No
on the deicer P.C. board and
outdoor terminal block correct.
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