Mitsubishi Electric MSZ-D30NA Service Manual page 28

• Unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch.
Indoor unit does not operate.
• OPERATION INDICATOR lamp flashes ON and OFF every 0.5-second.
Outdoor unit does not operate.
D How to check miswiring and serial signal error
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 other
away.
Is serial signal
error indicated 6 • Attach a fi lter
No
minutes later? on remote
control receiv-
Yes
ing section
of the indoor
unit.
B
Turn OFF the power supply.
Is there rated voltage AC 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? <Confi rmation 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
B
connecting wire is not miswiring.
Short-circuit outdoor terminal block S2
and S3. 1
Turn ON the power supply.
Does the LED on the inverter 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 out-
door 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? <Confi rmation of serial signal>
Yes
Is there rated voltage between
indoor terminal block S1 and S2?
<Confi rmation of power voltage>
Yes
Replace the indoor electronic control P.C. board.
Be sure to release the failure-mode recall function
after checking.
28 28
Check the power supply.
No
Check the wiring.
No
No
Is there any miswiring, poor
contact, or wire disconnec-
tion of the indoor/outdoor
No
connecting wire?
Is fuse (F65) broken?
No
1. Miswiring may damage indoor electronic control
P.C. board during the operation.
Be sure to confi rm the wiring is correct before
the operation starts.
Replace the inverter P.C. board or the
outdoor electronic control P.C. board.
No
2
(Lighted
or not
2. Be careful to the residual
lighted)
voltage of smoothing capacitor.
Is there any error of the in-
door/outdoor connecting wire,
such as the damage of the wire,
No
intermediate connection, poor
contact to the terminal block?
No
Is there any error of the in-
door/outdoor connecting wire,
such as the damage of the wire,
No
intermediate connection, poor
contact to the terminal block?
No
Correct them.
Yes
Replace the indoor/out-
Yes
door connecting wire.
Replace the indoor/out-
Yes door connecting wire.