Mitsubishi Electric MUH-GA-VB Series Service Manual page 17

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.
After 3 minutes, mis-wiring is indicated
(0.5-second ON, 0.5-second OFF)
lamp on indoor unit.w
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.
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. )
• Turn OFF the power supply. (indoor unit)
• Connect indoor/ outdoor connecting
wire.
Turn ON the power supply. (outdoor unit)
Is there 5V DC between J205 + -J101 -
(MUH-GA50VB)/ J101 + -J401 - (MUH- GA60
/GA80VB) on the deicer P.C. board?
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.)
Refer to outdoor unit service manual.
All manuals and user guides at all-guides.com
Start
on OPERATION INDICATOR
Is this mis-wiring, poor contact,
or wire disconnection?
No
Yes
Is there 230V AC between L-N
on the outdoor terminal block?
Yes
Yes
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.
17