Mitsubishi Electric MSZ-D30NA Service Manual page 28

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 the emergency operation switch.
• Reinstall
either the unit
or the light
away from
Is serial signal
each other.
error indicated
• Attach a filter
No
6 minutes later?
on remote
control receiv-
Yes
ing section
of the indoor
B unit.
OBH501D
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 the 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
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 V 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.
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 confirm the wiring is correct before the
operation starts.
Replace the inverter P.C. board or the
outdoor electronic control P.C. board.
No
*2
(Lit or
not lit)
*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,
No
intermediate connection, poor
contact to the terminal block?
No
Is there any error of the indoor/
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-
door connecting wire.
Yes