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How to check mis-wiring and serial signal error
Serial signal error is indicated.
(0.5-sec. ON, 0.5-sec. OFF)
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)
•Turn ON the power supply(indoor/outdoor unit).
•Press once EMERGENCY OPERATION switch.
•3 min. later, check the self-check result
displayed on OPERATION INDICATOR
lamp on indoor unit.
w 2
Start
Turn OFF the power supply(indoor/outdoor unit).
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 the outdoor unit "MUH" type?
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
Set the switch(SW2-2) on the indoor electronic
control P.C. board to MU or MUX type.
w1
Yes
Does the unit operate?
OK
Yes
No
No
Refer to the
"Instruction of
troubleshooting."
w 2 Short circuit of JPG and JPS on the indoor electronic control
P.C. board enables self-check to be displayed in 3 seconds.
w 1 Set the switch(SW2-2) on indoor electronic control P.C. board to
MU or MUX type, when the outdoor unit is MU or MUX type.
If the setting is MUH or MXZ type, the unit does not work.
Is there 5V DC between J205 + –J101 - on the deicer P.C. board?
As for indoor unit MSC type, refer to service manual OB385 or OB393.
When OPERATION INDICATOR lamp flashes 0.5-second intervals or 1-time.
Outdoor unit does not operate.
OB387-1.qxp 05.2.21 10:03 AM Page 26