Mitsubishi Electric MUZ-GC25VA-E1 Service Manual page 36

• 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-seconds.
Outdoor unit doesn't operate.
How to check mis-wiring and serial signal error (when outdoor unit does not work)
N
Turn OFF the power supply.
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
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 upper 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 inverter P.C. board
or the outdoor electronic control P.C. board
repeat "3.6-second-OFF and 0.8-second-ON
quick blinking"? W3
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 indoor terminal block S2
and S3? <Confirmation of serial
signal>
Is there rated voltage between
indoor terminal block S1 and S2?
<Confirmation of power voltage>
Yes
Is there 2V DC or less between CN10A3(+)
and JPG(GND)(–) on the indoor electronic
control P.C. board?
Yes
Is there 2V DC or less between
CN10A4(+) and JPG(GND)(–)
on the indoor electronic control
P.C. board?
Replace the indoor power /
terminal P.C. board.
Be sure to release the failure-mode recall function after checking.
36
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?
W1. Mis-wiring may damage indoor P.C. board during the
operation.
Be sure to confirm the wiring is correct before the
operation starts.
W3. Be sure to check this within 3 minutes after turning ON.
After 3 minutes, LED blinks 6 times. Even when
the inverter P.C.board or the outdoor electronic control
P.C.board is normal, LED blinks 6 times after 3 minutes.
Replace the inverter P.C. board or
No
the outdoor electronic control P.C.board.
(Lighted or W2
not lighted)
W2 Be careful to the residual
voltage of smoothing capacitor.
Is there any error of the
indoor/outdoor connecting wire,
No
such as the damage of the wire,
intermediate connection, poor
contact to the terminal block?
No
Is there 2V DC or less between
CN10A4(+) and JPG(GND)(–)
on the indoor electronic control
P.C. board?
No Yes
Replace the indoor
electronic control P.C. board.
Yes
Correct them.
No
Replace the
Yes
indoor/outdoor
connecting wire.
No
Yes
No