Mitsubishi Electric MSZ-JP12WA-U Service Manual page 24

D How to check miswiring and serial signal error
Is the bus-bar voltage of the inverter P.C. board or the outdoor electronic control 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 or the outdoor electronic control 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 outdoor terminal block S2 and S3.
Turn ON the power supply.
Is there rated voltage between indoor terminal block S1 and S2?
<Confirmation of power voltage>
Is there amplitude of 10 to 20 V DC between indoor terminal block S2
and S3? <Confirmation of serial signal>
A
• Turn OFF inverter-controlled lighting
equipment.
• Turn OFF the power supply and then
turn ON again.
• Press the emergency operation switch.
• Reinstall
either the unit
or the light
away from
Is serial signal
each other.
error indicated
• Attach a filter
No
6 minutes later?
on remote
control receiv-
Yes
ing section
of the indoor
B unit.
OBH820A
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 the emergency operation switch once.
Does the 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
B
connecting wire is not miswiring.
Bridge the outdoor terminal block S2 and
S3. *1
Turn ON the power supply.
Yes
Yes
Yes
Yes
Is there 2 V DC or less between CN10A (+)
and JPG (GND)(-) on the indoor electronic
control P.C. board?
Yes
Is there 2 V DC or less between
CN10A (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
No
Replace the indoor power
P.C. board and the indoor
terminal P.C. board
24
Check the power supply.
No
No
Is there any miswiring, poor
contact, or wire disconnec-
tion of the indoor/outdoor
No
connecting wire?
*1. Miswiring may damage indoor electronic control P.C.
board during the operation.
Be sure to confirm 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. *2
No
(Lit or not
lit)
*2. Be careful of the residual voltage of smoothing
capacitor.
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.
No
No
Is there 2 V DC or less between
CN10A (+) and JPG (GND)(-) on
the indoor electronic control P.C.
board?
Yes
Replace the indoor elec-
tronic control P.C. board.
Check the wiring.
No
Correct them.
Yes
No
Check of power supply.
(Refer to the outdoor service
No
manual.)
Yes
No