Mitsubishi Electric MUZ-FA25VA-E1 Service Manual page 52

Mitsubishi ilmalämpöpumput huoltaa ja korjaa: Jäähdytinpalvelu RefGroup Oy
When POWER lamp flashes ON and OFF in every 0.5-second.
Outdoor unit doesn't operate.
How to check mis-wiring and serial signal error (when outdoor unit does not work)
O
Inverter P.C.board
(Parts side)
LED
Blinking
A
· Turn OFF inverter-controlled lighting
equipment.
· Turn OFF the power supply and then
turn ON it again.
· Press EMERGENCY OPERATION
switch.
· Reinstall
either the
unit or the
light each
Is serial signal
No
other away.
error indicated
· Attach a filter
6 minutes later?
on receiving
Yes
section of
the indoor
B
unit.
Turn OFF the power supply.
Is there rated voltage of
230V AC in the power
supply?
Yes
Turn ON the power supply.
Is there 230V AC between
outdoor terminal block S1 and
S2?
Yes
Press EMERGENCY OPERATION switch.
Does POWER lamp light
up? <Confirmation of the power to the indoor
unit>
Yes
Is the self-check of the indoor unit displayed 6
minutes after?
Yes
Serial signal error display
POWER lamp blinks
quickly.
A
Turn OFF the power supply.
Check once more if the indoor/outdoor
B
connecting wire is not mis-wiring.
Short-circuit outdoor terminal block S2 and
S3.
W1
Turn ON the power supply of the outdoor unit.
In 3 minutes after turning ON the
power supply of the outdoor unit, does
the LED on the inverter P.C. board
repeat quick blinking "3.6-second-OFF
and 0.8-second-ON"?
Be sure to check above in 3 minutes
after turning ON. After 3 minutes, LED
blinks 6 times. When the inverter P.C.
board is normal, LED also blinks 6
times after 3 minutes.
Yes
Remove the short-circuit between
outdoor terminal block S2 and S3.
Is there amplitude of 10 to 20V DC
between outdoor terminal block S2
and S3? <Confirmation of serial
signal>
Yes
Is there 230V AC between outdoor
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.
As for indoor unit, refer to service manual OB371.
35
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No
Check the power
supply.
No
Check the wiring.
No
Is there any mis-
wiring, poor contact,
No
or wire 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
No
P.C. board.
(Lighting) W2
W2 Be careful to the residual
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
No
contact to the terminal block?
Yes
Make them sure.
Replace the
Yes
indoor/outdoor
connecting.
Replace the
Yes
indoor/outdoor
connecting.