How To Check Mis-Wiring And Serial Signal Error - Mitsubishi Electric MXZ-2A40VA Service Manual

• When unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch.
Indoor unit does not operate.
• When OPERATION INDICATOR lamp flashes ON and OFF in every 0.5-second.
Outdoor unit does not operate. (LED display : Both LED1 and LED 2 lighting)
B B How to check mis-wiring and serial signal error (when outdoor unit does not work)
Outdoor display P.C. board
LED1 LED2
Blinking
LED 1 LED 2
Unit A Unit B
Outdoor electronic control P.C. board
(Parts side)
LED3 LED2 LED1
Blinking
LED indication
LED 3 LED 2 LED 1
Lit Unit B Unit A
Not Lit Unit D Unit C
The LED indication
for unit A and unit B,
and unit C and unit D
interchanges at a
interval of 15 seconds.
A
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn ON again.
· Press EMERGENCY OPERATION
switch.
· Reinstall
either the
unit or the
light each
Is serial signal
other away.
No
error indicated
· Attach a filter
6 minutes later?
on remote
control
receiving
section of
Yes
the indoor
unit.
B
Turn OFF the power supply.
Is there rated voltage in
the power supply?
Yes
Turn ON the power supply.
Is there rated voltage between
outdoor terminal block S1 and
S2?
Yes
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION
INDICATOR lamp light up?
<Confirmation of the power to the indoor unit>
Yes
Is serial signal error indicated 6 minutes later?
Yes
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not mis-wiring.
B
Short-circuit outdoor terminal block S2 and
S3.
W1
Turn ON the power supply.
Does the LED on the outdoor display P.C.
board or the outdoor electronic
control P.C. board repeat "3.6-second-OFF
and 0.8-second-ON quick blinking"?
Yes
Turn OFF the power supply.
Remove the short-circuit between
outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there amplitude of 10 to 20V DC
between outdoor terminal block S2
and S3? <Confirmation of serial
signal>
Yes
Is there rated voltage between
indoor terminal block S1 and S2?
<Confirmation of power voltage>
Yes
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode
recall function after checking.
Refer to indoor unit service manual.
64
No
Check the power
supply.
No
Check the wiring.
No
Is there any mis-wiring,
poor contact, or wire
No
disconnection of the
indoor/outdoor
connecting wire?
No
W1. 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.
Replace the inverter P.C. board or
No
the outdoor electronic control P.C. board.
(Lighted W2
or
W2 Be careful to the residual
not lighted)
voltage of smoothing capacitor.
Is there any error of the
indoor/outdoor connecting wire,
such as the damage of the wire,
intermediate connection, poor
No
contact to the terminal block?
No
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
No
Yes
Make them correct.
Replace the
Yes
indoor/outdoor
connecting wire.
Replace the
Yes
indoor/outdoor
connecting wire.