Mitsubishi Electronics MUZ-D30NA, MUZ-D36NA, U1 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.

•OPERATION INDICATOR lamp flashes ON and OFF in every 0.5 seconds. Outdoor unit doesn’t operate.

H How to check miswiring and serial signal error

Turn OFF the power supply.

Is there rated voltage in the
		Check the power supply.
power supply?	No

Yes

Turn ON the power supply.

Is there rated voltage between outdoor terminal block S1 and

S2?No

Yes

Press EMERGENCY OPERATION switch once.

Does the left lamp of OPERATION INDICA- TOR lamp light up? <Confirmation of the power to the indoor unit>

Yes

Is serial signal error indicated 6 minutes later?

Yes

Check the wiring.

No

Is there any miswiring, poor contact, or wire disconnec-

No tion of the indoor/outdoor Yes Correct them. connecting wire?

Is fuse (F65) broken? No

Outdoor electronic control P.C. board (Parts side)

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.

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.

LED2 LED1

Lighted Blinking

A

•Turn OFF inverter-controlled lighting equipment.

•Turn OFF the power supply and then turn ON again.

•Press EMERGENCY OPERATION switch.

Does the LED on the inverter P.C. board or
			Replace the inverter P.C. board or
the outdoor electronic control P.C. board
			the outdoor electronic control P.C. board.
repeat "3.6-second-OFF and 0.8-second-		No
			2
ON quick blinking"? 3		(Lighted
	Yes	or not	2. Be careful to the residual
		lighted)	voltage of smoothing capacitor.

Turn OFF the power supply.			Is there any error of the in-
Remove the short-circuit between
outdoor terminal block S2 and S3.			door/outdoor connecting wire,			Replace the indoor/
Turn ON the power supply.			such as the damage of the wire,			outdoor connecting
		No			Yes
Is there amplitude of 10 to 20 VDC			intermediate connection, poor			wire.
between outdoor terminal block S2 and			contact to the terminal block?
S3? <Confirmation of serial signal>				No
	Yes
			Is there any error of the in-
Is there rated voltage between
			door/outdoor connecting wire,			Replace the indoor/

Is serial signal error indicated 6 minutes later?

Yes

B

No

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

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

indoor terminal block S1 and S2?		No	such as the damage of the wire,			outdoor connecting
					Yes
<Confirmation of power voltage>			intermediate connection, poor			wire.
	Yes		contact to the terminal block?
				No

Replace the indoor electronic control P.C. board.

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

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