How to check mis-wiring and serial signal error (when outdoor unit does not work)
E
17
When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
1. Turn OFF the power supply
(indoor/outdoor unit)
and disconnect indoor and outdoor connecting wire on indoor side.
2. Short-circuit between indoor terminal block
N
and
3
.
3. Turn ON the power supply
(indoor unit)
and press once EMERGENCY OPERATION switch.
During EMERGENCY OPERATION,
is there 10V DC between both ends
of R601?
(By tester, the stylus is between 5 ~10V)
Start
No
No
Is there 20V DC between both ends of
R132 on indoor electronic control P.C.
board ?
( By tester, the stylus is between 0 ~ 20V. )
•Turn OFF the power supply(indoor unit).
•Connect ON indoor and outdoor connecting wire.
Is this mis-wiring, poor contact,
or disconnection of wire?
Make them sure.
Replace the indoor electronic
control P.C. board.
Turn ON the power supply(outdoor unit).
Is there 230V AC between outdoor terminal
block
L
-
N
(TB1)?
No
Check the outdoor power supply,
power supply cord and
connection.
Yes
Turn ON the power supply(indoor unit).
No
Replace the deicer P.C. board.
Yes
No
Make the wiring between CN730
on the deicer P.C. board and
outdoor terminal block correct.
Replace the deicer P.C. board.
Yes
Yes
Yes
Is there 5V DC between J205 + –J101 - (MUCFH-GA35VB/GA50VB)/
J101 + –J401 - (MUCFH-GA60VB) on the deicer P.C. board?
As for outdoor unit MUCFH type, refer to the service manual OB381.
As for outdoor unit MXZ type, refer to the service manual OB319 REVISED EDITION-A.
OB380--1.qxp 04.12.23 17:33 Page 17
