24
Yes
Yes
How to check mis-wiring and serial signal error (when outdoor unit does not work)
B
Start
1. Turn OFF power supply and disconnect indoor/ outdoor unit connecting wire of the indoor unit.
2. Short-circuit between indoor terminal block and .
3. Turn ON power supply and press EMERGENCY OPERATION switch.
•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 and ?
Is there 5V DC between J205 -J101 (MUCFH-A18WV)/
J101 -J401 (MUCFH-A24WV) 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.)
Replace the deicer 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.
Replace the indoor electronic control
P.C. board.
w
1 Short circuit of JPG and JPS
on the electronic control P.C.
board enables self-check to
be displayed in 3 seconds.
Repair wiring.
Is there mis-wiring, poor contact, or wire disconnection?
N
3
3 minutes later, is there 20V DC between both ends
of R132?
w
1
(By tester, the stylus is between 0 ~ 20V.)
3
N
+
–
Yes
Yes
No
No
No
No
No
Yes
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
+
–
As for indoor unit, refer to the service manual OB336.
OB337B--1.qxp 05.7.6 11:00 AM Page 24
