Mitsubishi Electronics Understanding the Mitsubishi Failure Mode Recall Function for Air Conditioners

9-2. Failure mode recall function

Outline of the function

This air conditioner can memorize the abnormal condition which has occurred once.

Even though LED indication listed on the troubleshooting check table disappears, the memorized failure details can be recalled.

This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.

1. Flow chart of the indoor/outdoor unit failure mode recall function

Operational procedure

The cause of abnormality cannot be found because the abnormality doesn't recur.

Setting up the failure mode recall function

Turn ON the power supply.

1While pressing both OPERATION SELECT

button and TOO COOL button on the remote controller at the same time, press RESET button.

2First, release RESET button.

And release the other two buttons since all LCD in operation display section of the remote controller is displayed after 3 seconds.

W1

Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature is displayed).

With the remote controller headed towards the indoor unit, press TOO COOL or TOO WARM button to adjust the set temperature to 24:.

1While pressing both OPERATION SELECT button and TOO COOL button on the

remote controller at the same time, press RESET button.

2First, release RESET button.

And release the other two buttons since all LCD

in operation display section of the remote controller is displayed after 3 seconds.

W1. Regardless of normal or abnormal, a short beep is emitted once as the signal is received.

Does POWER lamp on the indoor

unit blink at the interval of 0.5 seconds?

Blinks: Either indoor or outdoor unit is abnormal. Beep sounds are emitted at the same timing of the blinking of POWER lamp. W2

Judgment of indoor/outdoor abnormality	Yes
	(Blinks)

No

(OFF)

Indoor unit is normal.

There is a possibility that the plasma or outdoor unit is abnormal. Confirm the presence of abnormality according to the flow chart of the the prasma unit or detailed outdoor unit failure mode recall function.

Before blinking, does POWER		Yes
lamp stay ON for 3 seconds?
Stays ON for 3 seconds (without beep):
The outdoor unit is abnormal.
	No
The indoor unit is abnormal.			The outdoor unit is abnormal.
Check the blinking pattern, and refer to confirm the			Check the blinking pattern, and refer to confirm the abnormal point.
abnormal point(9-2.4.).			Make sure to check at least two consecutive blinking cycles. W3
Make sure to check at least two consecutive blinking cycles. W2

Releasing the failure mode recall function

Release the failure mode recall function by the following procedures.

1With the remote controller headed towards the indoor unit, press any button that is not used in this failure mode recall function (e.g. TIMER button) .

OR

1Turn OFF the power supply and turn ON it again.

2Press RESET button of the remote controller.

•As for outdoor unit MUZ type, refer to service manual OB372. As for outdoor unit MXZ type, refer to service manual OB377.

Repair the defective parts.

Deleting the abnormal condition

1After repairing the unit, recall the failure mode again according to "Setting up the failure mode recall function" mentioned above.

2Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.

3Release the failure mode recall function according to "Releasing the failure mode recall function" mentioned above.

Note1.Make sure to release the failure mode recall function once it's set up, otherwis the unit cannot operate properly. 2.If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.

W2. Blinking pattern when the indoor unit is abnormal:

Blinking at 0.5-

Blinking at 0.5-

2.5-second OFF

second interval

2.5-second OFF second interval

ON

OFF

Beeps

Beeps

Beeps

Repeated cycle

Repeated cycle

Repeated cycle

W3.Blinking pattern when the outdoor unit is abnormal:

Blinking at 0.5-

Blinking at 0.5-

2.5-second OFF

3-second ON

second interval

2.5-second OFF

3-second ON

second interval

ON

OFF

No beep

Beeps

No beep

Beeps

Repeated cycle

Repeated cycle

Repeated cycle

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