How To Check Miswiring And Serial Signal Error - Mitsubishi Electric MUZ-FH09NA Service Manual

M How to check miswiring and serial signal error
Is the bus-bar voltage of the inverter P.C. board normal?
(Refer to "TEST POINT DIAGRAM AND VOLTAGE" in the outdoor service manual.)
Does the LED on the inverter P.C. board repeat
"3.6-second-OFF and 0.8-second-ON quick blinking"? 3
Turn OFF the power supply.
Remove the bridge between the outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there rated voltage between the indoor terminal block S1 and S2?
<Confi rmation of power voltage>
Is there amplitude of 10 to 20 VDC between the indoor terminal block
S2 and S3? <Confi rmation of serial signal>
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
OBH584A
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? <Confi rmation 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
B
connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3. 1
Turn ON the power supply.
Is there 2 VDC or less between CN202
and JPG (GND)(-) on the indoor electronic
control P.C. board?
Yes
• Reinstall
either the unit
or the light
away from
each other.
Replace the indoor power
• Attach a fi lter
P.C. board.
on remote
control receiv-
ing section
of the indoor
unit.
No
Yes
Yes
No
Yes
No
Yes
A
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 is normal, LED blinks 6 times after 3
minutes.
Yes
No
(Lighted
Yes
or not
lighted)
Check the wiring
If there are any error of the indoor/outdoor connecting wire:
such as the damage of the wire, intermediate connection,
No
and/or poor contact to the terminal block, replace the indoor/
outdoor connecting wire.
Yes
No
Yes
(+)
No
Is there 2 VDC or less between
CN202A (+) and JPG (GND)(-)
on the indoor electronic control P.C.
board?
No Yes
Replace the indoor elec-
tronic control P.C. board.
39
NOTE: Refer to the indoor unit service manual.
Check the power supply.
No
Check the wiring.
Is there any miswiring,
poor contact, or wire
disconnection of the
Yes
indoor/outdoor connect-
ing wire?
No
Check of power supply.
(Refer to the outdoor
No
service manual.)
Replace the inverter P.C. board . 2
2. Be careful of the residual voltage of
smoothing capacitor.
Is there 2 VDC or less between
CN202 (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
No
Correct them.
Yes