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

•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.

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)

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

•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			Is there any error of the in-
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
Turn ON the power supply.		No	such as the damage of the wire,		Yes	outdoor connecting
Is there amplitude of 10 to 20 VDC			intermediate connection, poor			wire.
between outdoor terminal block S2 and			contact to the terminal block?
between outdoor terminal block S2 and			contact to the terminal block?
S3? <Conﬁrmation of serial signal>				No
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

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

Replace the indoor electronic control P.C. board.

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

MUY-D36NA, MUZ-D30NA, U1, MUY-D30NA, MUZ-D36NA specifications

Mitsubishi Electronics has long been at the forefront of innovation in heating and cooling solutions, and its latest lineup of multi-zone air conditioning units—MUZ-D36NA, MUY-D30NA, U1, MUZ-D30NA, and MUY-D36NA—reflects this commitment to quality and efficiency. Designed for both residential and commercial applications, these units offer advanced features that enhance comfort and energy savings.

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Mitsubishi's advanced climate control technologies set these models apart. The system can be easily controlled using a user-friendly remote or via a mobile app, offering convenience and flexibility. The intelligent temperature control ensures that rooms are heated or cooled consistently, regardless of external conditions.

Installation versatility is another highlight. These units can be configured for multi-zone systems, allowing for tailored comfort in different spaces. The compact and sleek design makes them suitable for various installations, whether in homes, offices, or retail environments.

Furthermore, the MUZ-D and MUY-D series are equipped with quiet operation features, ensuring minimal disruption in both residential and commercial settings. This is particularly beneficial in spaces where noise could be a concern, such as bedrooms or conference rooms.

In summary, Mitsubishi's MUZ-D36NA, MUY-D30NA, U1, MUZ-D30NA, and MUY-D36NA offer a powerful combination of energy efficiency, advanced filtration, intelligent controls, and quiet operation. These features make them an excellent choice for anyone looking to enhance indoor comfort while minimizing environmental impact. Whether it's for a single room or an entire building, these units are engineered to deliver reliable performance year-round.