Mitsubishi Electric MSZ-SF15VA-E1 Service Manual page 27

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.
Is serial signal
error indicated 6
No
minutes later?
Yes
B
OBH555D
Turn OFF the power supply.
Is there rated voltage in
the power supply?
Turn ON the power supply.
Is there rated voltage between
the outdoor terminal block S1
and S2?
Press EMERGENCY OPERATION switch once.
Does the left lamp of OPERATION
INDICATOR lamp light up?
<Confirmation of the power to the indoor unit>
Is serial signal error indicated 6 minutes later?
Turn OFF the power supply.
Check once more if the indoor/outdoor
connecting wire is not miswiring.
B
Bridge the outdoor terminal block S2 and
S3.
1
Turn ON the power supply.
Does the LED on the outdoor electronic
control P.C. board repeat "3.6-second-OFF
and 0.8-second-ON quick blinking"?
Turn OFF the power supply.
Remove the bridge between
the outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there amplitude of 10 to 20V DC
between the outdoor the terminal
block S2 and S3?
<Confirmation of serial signal>
Is there rated voltage between the
indoor terminal block S1 and S2?
• Reinstall
<Confirmation of power voltage>
either the unit
or the light
away from
each other.
• Attach a f lter
on remote
control receiv-
Replace the indoor electronic control P.C. board.
ing section
of the indoor
Be sure to release the failure-mode
unit.
recall function after checking.
No
Yes
No
Yes
No
Yes
No
Yes
A
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.
No
(Lighted
or
not lighted)
Yes
No
Yes
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
27
Check the power
supply.
Check the wiring.
Is there any miswiring,
poor contact, or wire
Yes
disconnection of the
indoor/outdoor
connecting wire?
No
Replace the outdoor electronic control
P.C. board.
2
2 Be careful of residual
voltage of smoothing capacitor.
Yes
No
Correct them.
Replace the
indoor/outdoor
connecting wire.