Mitsubishi Electric MCFH-A12WV Service Manual page 17

When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
How to check mis-wiring and serial signal error (when outdoor unit does not work)
E
Repair wiring.
3 minutes later, is there 20V DC between both ends
of R132? w 1
(By tester, the stylus is between 0 ~ 20V.)
•Turn OFF power supply.
•Reconnect indoor/ outdoor unit connecting wire.
•Turn ON power supply.
3 minutes later, when EMERGENCY OPERATION switch is pressed ,
is there 12V DC between outdoor terminal block
Is there 5V DC between J9
J101 + -J401 (MUCFH-A24WV) on the deicer P.C. board?
–
Is there 10V DC between both ends of R601 on the deicer P.C.
board?
(By tester, the stylus is between 5 ~10V DC)
Replace the deicer P.C. board.
Yes
Is there mis-wiring, poor contact, or wire disconnection?
1. Turn OFF power supply and disconnect indoor/ outdoor unit connecting wire of the indoor unit.
2. Short-circuit between indoor terminal block
3. Turn ON power supply and press EMERGENCY OPERATION switch.
Yes
and
3
Yes
+
-J8 (MUCFH-A12/A18WV)/
–
Yes
Yes
As for outdoor unit MUCFH type, refer to the service manual OB337.
As for outdoor unit MUH type, refer to the service manual OB331.
As for outdoor unit MXZ type, refer to the service manual OB319.
Start
No
and .
N
3
No
No
?
N
No
No
17
w 1 Short circuit of JPG and JPS
on the electronic control P.C.
board enables self-check to
be displayed in 3 seconds.
Replace the indoor electronic control
P.C. board.
Rectify indoor/ outdoor unit
connecting wire.
Check and rectify fuse and varistor on the
deicer P.C. board.
Rectify indoor/ outdoor unit
connecting wire.