Mitsubishi Electric MFZ-KA25VA Service Manual page 22

10-2. Failure mode recall function
Outline of the function
This air conditioner can memorize the abnormal condition which has occurred once.
Even though OPERATION INDICATOR lamp indication listed on the troubleshooting check table (10-4.) disappears, the
memorized failure details can be recalled.
This mode is very useful when the unit needs to be repaired for the abnormality which doesn't recur.
1. Flow chart of failure mode recall function for the indoor/outdoor unit
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.
1 While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller at the same
time, press RESET button.
2 First, release RESET button.
And release the other two buttons after all LCD except the set
temperature in operation display section of the remote controller is
displayed after 3 seconds.
Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature
is displayed) with the remote controller headed towards the indoor unit. W1
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 are emitted at the same timing
as the blinking of the left lamp of
OPERATION INDICATOR lamp. W2
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 outdoor unit is abnormal.
The indoor unit is abnormal.
Check the blinking pattern, and confirm the
abnormal point with the indoor unit failure mode table (10-2. 2.).
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.
Turn OFF the power supply and turn it ON again.
Press RESET button of the remote controller.
Repair the defective parts.
Deleting the abnormal
memorized condition
1After repairing the unit, recall the failure mode again according to "Setting up the failure
mode recall function" mentioned above.
2Press OPERATE/STOP(ON/OFF) button of the remote controller (the set temperature is
displayed) with the remote controller headed towards the indoor unit. W1
3Press EMERGENCY OPERATION switch so that the memorized abnormal condition is deleted.
4Release 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, otherwise 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-
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
Yes
(Blinks)
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
Indoor unit is normal.
No
But the outdoor unit might be abnormal because there are some
(OFF)
abnormalities that are not memorized in the indoor unit.
Confirm if outdoor unit is abnormal according to the flow chart of the
detailed outdoor unit failure mode recall function.
Yes
The outdoor unit is abnormal.
Check the blinking pattern, and confirm the abnormal point with the
outdoor unit failure mode table (Refer to outdoor unit service manual).
Make sure to check at least two consecutive blinking cycles. W3
As for outdoor unit, refer to outdoor unit service manual.
Beeps Beeps
Repeated cycle
2.5-second OFF 3-second ON
No beep
Repeated cycle
22
1 While pressing both OPERATION SELECT
button and TOO COOL button on the remote controller
at the same time, press RESET button.
2 First, release RESET button.
And release the other two buttons after all LCD except the
set temperature 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.
Blinking at 0.5-
second interval
Beeps
Repeated cycle