Mitsubishi Electronics MSZ-FD35VA, MSZ-FD25VA How to check miswiring and serial signal error

•Unit cannot operate neither by the remote controller nor by EMERGENCY OPERATION switch. Indoor unit does not operate.

•POWER lamp flashes ON and OFF every 0.5-seconds. Outdoor unit does not operate.

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.

Turn OFF the power supply.

Is there rated voltage

Check the power

in the power supply?

No

supply.

Yes

Turn ON the power supply.

Is there rated voltage between

Check the wiring.

outdoor terminal block S1 and

No

S2?

Yes

Press EMERGENCY OPERATION switch once.

Does AREA-L lamp light up?

<Confirmation of the power to the indoor unit>

No

Yes

Is there any miswiring,

Is serial signal error indicated 6 minutes later?

poor contact, or wire

Yes

No

disconnection of the

Correct them.

indoor/outdoor

Yes

connecting wire?

No

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

W1. Miswiring may damage indoor electronic control

S3.

P.C. board during the operation.

W1

Be sure to confirm the wiring is correct before the

operation starts.

W3. Be sure to check this within 3 minutes after turning

ON. After 3 minutes, LED blinks 6 times. Even when

Turn ON the power supply.

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)

Does the LED on the inverter P.C. board

No

Replace the inverter P.C. board or

or the outdoor electronic control P.C.board

the outdoor electronic control P.C.board.

repeat "3.6-second-OFF and 0.8-second-ON (Lighted or

W2

quick blinking"? W3

not lighted)

Yes

W2 Be careful to the residual

voltage of smoothing capacitor.

Turn OFF the power supply.

Remove the short-circuit between

Is there any error of the

outdoor terminal block S2 and S3.

indoor/outdoor connecting wire,

Replace the

Turn ON the power supply.

such as the damage of the wire,

indoor/outdoor

Is there amplitude of 10 to 20 VDC

Yes

No

intermediate connection, poor

connecting wire.

between outdoor terminal block S2

and S3? <Confirmation of serial

contact to the terminal block?

signal>

No

Yes

Is there any error of the

Is there rated voltage between

indoor/outdoor connecting wire,

Replace the

indoor terminal block S1 and S2?

such as the damage of the wire,

Is serial signal

error indicated 6 minutes later? No

Yes

B

·Reinstall either the unit or the light each other away.

·Attach a filter on remote control receiving section of the indoor unit.

<Confirmation of power voltage>	No intermediate connection, poor	Yes	indoor/outdoor
			connecting wire.
	contact to the terminal block?
Yes
	No

Replace the indoor electronic control P.C. board.

Be sure to release the failure-mode recall function after checking.

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