Mitsubishi Electric MSZ-LN18VG2V-E3 Service Manual page 50

MXZ Type
LED indication
for communication status
Communication status is indicated by the
LED.
Unit status
Blinking: Normal communication
Lit: Abnormal communication or
not connected
Pattern 1 and 2 is repeatedly displayed
alternately. Each pattern is displayed for
10 seconds.
NOTE: "Lit" in the table below does not
indicate abnormal communication.
Outdoor control P.C. board
LED1 LED2 LED3
Blinking
Pattern LED 1 LED 2
Unit A Unit B
1
status
status
Unit C
Unit D
2
status
status
Unit E
3
status
OBH766G
Turn OFF the power supply.
Is there rated voltage in the power supply?
Turn ON the power supply.
Is there rated voltage between outdoor terminal block S1 and S2?
Press the emergency operation switch once.
Does the indoor POWER lamp light up?
<Confirmation of the power to the indoor unit>
Is serial signal error indicated 6 minutes later?
LED 3
Lit
• Turn OFF inverter-controlled lighting equipment.
Not lit
• Turn OFF the power supply and then turn ON again.
• Press the emergency operation switch.
Blinking
Is serial signal error indicated 6 minutes later?
• Turn OFF the power supply.
• Check once more if the indoor/outdoor connecting
wire is not miswiring.
• Remove the indoor/outdoor connecting wire from
outdoor terminal block S3.
• Short-circuit outdoor terminal block S2 and S3.*1
Turn ON the power supply.
Does the LED on the outdoor control P.C. board
repeat "3.6-second-OFF and 0.8-second-ON
quick blinking"?
• Turn OFF the power supply.
• Remove the bridge between outdoor terminal block
S2 and S3.
• Turn ON the power supply.
Is there amplitude of 10 to 20 VDC between
outdoor terminal block S2 and S3?
<Confirmation of serial signal>
Is there rated voltage between indoor terminal
block S1 and S2?
<Confirmation of power voltage>
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode recall function after checking.
No
Yes
Yes
No
Yes
Is there any miswiring,
poor contact, or wire
disconnection of the
No
indoor/outdoor connect-
Yes
ing wire?
• Reinstall either the unit or the light away
from each other.
• Attach a filter on remote control receiving
No
section of the indoor unit.
Yes
No
(Lit or
not lit)
Yes
No
Yes
No
Yes
50
Check the power supply.
Check the wiring.
No
Correct them.
Yes
No
*1 Miswiring may damage indoor electronic control
P.C. board during the operation.
Be sure to confirm the wiring is correct before the
operation starts.
Replace the outdoor control P.C. board. *2
*2 Be careful of the residual voltage of smoothing
capacitor.
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?
No
Replace the
indoor/outdoor
Yes
connecting wire.