Mitsubishi Electric MXZ-2C20NA2, Service Manual

Page: 121 / 154

121
Is there rated voltage in
the power supply?
Is there any miswiring,
poor contact, or wire
disconnection of the
indoor/outdoor
connecting wire?
* 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.
No
(Lit or not lit)
No
Yes
No
Yes
Yes
Yes
No
Be sure to release the failure-mode
recall function after checking.
No
No
Yes
No
Yes
Yes
Yes
No
Yes
Refer to indoor unit service manual.
Turn OFF the power supply.
Turn ON the power supply.
Is there rated voltage between
outdoor terminal block S1 and
S2?
Does the left lamp of OPERATION
INDICATOR lamp light up?
<Confirmation of the power to the indoor unit>
Press EMERGENCY OPERATION switch once.
Check the power
supply.
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3.
* 1
B
Turn ON the power supply.
Check the wiring.
Correct them.
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 V DC
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.
* 2 Be careful of the residual
voltage of smoothing capacitor.
Replace the outdoor control P.C. board.
* 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?
Replace the
indoor/outdoor
connecting wire.
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 away
from each
other.
· Attach a filter
on remote
control
receiving
section of
the indoor
unit.
A
Is serial signal error indicated 6 minutes later?
No
Does the LED on the outdoor control P.C.
board repeat "3.6-second-OFF
and 0.8-second-ON quick blinking"?
LED indication
for communication status
Communication status is indicated
by the LED.
Blinking: normal communication
Lit: abnormal communication or
not connected
Pattern 1 and 2 is repeatedly displayed
alternately. Each pattern is displayed for
15 seconds.
NOTE: "Lit" in the table below does not
indicate abnormal communication.
Unit status
Outdoor control P.C. board
Blinking
LED1 LED2 LED3
LED 1 LED 3 LED 2 Pattern
1
2
3
Unit B
status
Unit C
status
Unit A
status
Unit D
status
Unit E
status
Not lit
Lit
Blinking
How to check miswiring and serial signal error (when outdoor unit does not work)
• When unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch.
Indoor unit does not operate.
• When OPERATION INDICATOR lamp blinks ON and OFF in every 0.5-second.
Outdoor unit does not operate.
OBH702N