Failure Mode Recall Function - Mitsubishi Electric MUZ-GA50VA-E1 Service Manual

11-2. 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 (11-4.) disappears, the memorized failure details
can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which does not 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 does not recur.
Setting up the failure mode recall function
Turn ON the power supply.
< Preparation of the remote controller >
While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller at the same time, press
RESET button.
First, release RESET button.
Hold down the other two buttons for another 3 seconds. Confirm that the indicators on
the LCD screen shown in the right figures are all displayed. Then release the buttons.
Press OPERATE/STOP (ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit.
Does the left lamp of OPERATION INDICATOR
lamp on the indoor unit blink at the interval of 0.5
seconds?
Blinks: Either indoor or outdoor unit is abnormal.
Beep is emitted at the same timing
as the blinking of the left lamp of
OPERATION INDICATOR lamp.
Judgment of indoor/outdoor abnormality
Before blinking, does the left lamp of
OPERATION INDICATOR lamp stay ON for 3
seconds?
Stays ON for 3 seconds (without beep):
The indoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the indoor unit
failure mode table (Refer to indoor unit service manual.)
Make sure to check at least two consecutive blinking cycles.
Releasing the failure mode recall function
Release the failure mode recall function by the following procedures.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Repair the defective parts.
Deleting the memorized abnormal condition
After repairing the unit, recall the failure mode again according to
"Setting up the failure mode recall function" mentioned above.
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 EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
Release 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 is set up, otherwise the unit cannot operate properly.
2. If the abnormal condition is not deleted from the memory, the last abnormal condition is kept memorized.
2. Blinking pattern when the indoor unit is abnormal:
Blinking at 0.5-
second interval
2.5-second OFF
ON
OFF
Repeated cycle
W3.Blinking pattern when the outdoor unit is abnormal:
2.5-second OFF
ON
OFF
2
Yes
(Blinks)
The outdoor unit is abnormal.
No
Blinking at 0.5-
second interval
2.5-second OFF
Beeps
Repeated cycle
Blinking at 0.5-
3-second ON second interval
No beep Beeps
Repeated cycle
1
1. Regardless of normal or abnormal condition, a short
beep is emitted once the signal is received.
No
Indoor unit is normal.
(OFF)
But the outdoor unit might be abnormal because there are some
abnormalities that can't be recalled with this way.
Confirm if outdoor unit is abnormal according to the detailed outdoor
unit failure mode recall function.(Refer to 11-2.2)
Yes
The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the
outdoor unit failure mode table (Refer to 11-2.3).
2 Make sure to check at least two consecutive blinking cycles.
Beeps Beeps
Repeated cycle
2.5-second OFF 3-second ON
No beep
Repeated cycle
28
Blinking at 0.5-
second interval
Beeps
Repeated cycle
3