20
How to check mis-wiring and serial signal error
D
When POWER lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate.
Is there rated voltage of
230V AC in the power
supply?
In 3 minutes after turning ON the
power supply of the outdoor unit, does
the LED on the inverter P.C. board
repeat quick blinking "3.6-second-OFF
and 0.8-second-ON"?
Be sure to check above in 3 minutes
after turning ON. After 3 minutes, LED
blinks 6 times. When the inverter P.C.
board is normal, LED also blinks 6
times after 3 minutes.
Is there any mis-wiring,
poor contact, or wire
disconnection of the
indoor/outdoor
connecting wire?
W
1. Mis-wiring may damage indoor electronic control
P.C. board during the operation.
Be sure to confirm the wiring is correct before the
operation starts.
(Lighting)
No
Yes
No
Yes
Yes
No
Yes
No
Yes
No
W
2 Be careful to the residual
voltage of smoothing capacitor.
Be sure to release the failure-mode
recall function after checking.
No
No
Yes
No
Yes
Serial signal error display
Yes
Yes
No
Yes
As for outdoor unit MUZ type,refer to service manual OB379.
As for outdoor unit MXZ type,refer to service manual OB377.
Inverter P.C.board
(Parts side)
LED
Blinking
Turn OFF the power supply.
Turn ON the power supply.
Is there 230V AC between
outdoor terminal block S1 and
S2?
Does the lefl lamp of OPERATION INDICATOR
lamp light up?
<Confirmation of the power to the indoor unit>
Press EMERGENCY OPERATION switch.
Check the power
supply.
Is the self-check of the indoor unit displayed 6
minutes after?
The left lamp of
OPERATION
INDICATOR lamp
blinks quickly.
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not mis-wiring.
Short-circuit outdoor terminal block S2 and
S3.
W
1
B
Turn ON the power supply of the outdoor unit.
Check the wiring.
Make them sure.
Remove the short-circuit between
outdoor terminal block S2 and S3.
Is there amplitude of 10 to 20V DC
between outdoor terminal block S2
and S3? <Confirmation of serial
signal>
Is there 230V AC between outdoor
terminal block S1 and S2?
<Confirmation of power voltage>
Replace the indoor electronic control P.C. board.
Replace the inverter
P.C. board.
W
2
Is there any error of the
indoor/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
Is there any error of the
indoor/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
Replace the
indoor/outdoor
connecting.
Replace the
indoor/outdoor
connecting.
Is serial signal
error indicated
6 minutes later?
Yes
No
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn ON again.
· Press EMERGENCY OPERATION
switch.
B
· Reinstall
either the
unit or the
light each
other away.
· Attach a filter
on receiving
section of
the indoor
unit.
A
OB378_--1qxp 05.1.17 12:55 Page 20
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