Indoor Unit - Mitsubishi Electric MSZ-FD25VA Service Manual

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
away from
each other.
Is serial signal
• Attach a fi lter
error indicated 6
No
minutes later? on remote
control receiv-
Yes
ing section
of 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 AREA-L 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"? 3
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.
31
Check the power supply.
No
Check the wiring.
No
No
Is there any miswiring,
poor contact, or wire
disconnection of the
No
indoor/outdoor connect-
ing wire?
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 opera-
tion starts.
3. 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.
(Except for outdoor unit of multi system type)
Replace the inverter P.C. board or the
outdoor electronic control P.C. board.
No
2
(Lighted
or not
2. Be careful of the residual voltage of
lighted)
smoothing capacitor.
Is there any error of the in-
door/outdoor connecting wire,
such as the damage of the
No wire, 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/outdoor
Yes
connecting wire.
Replace the indoor/out-
Yes door connecting wire.