Mitsubishi Electric CITY MULTI PUMY-P112VKM6 Service Manual page 74

6831 (E0)/6834 (E4): MA communication receive error
Abnormal points and detection methods
Detected in remote controller or indoor unit:
• The main or sub remote controller cannot receive signal
from indoor unit which has the "0" address.
• The sub remote controller cannot receive signal.
• The indoor controller board cannot receive signal from
remote controller or another indoor unit.
• The indoor controller board cannot receive signal.
Diagnosis of failure
Disconnect and reconnect the connec-
tor CN3A, then turn the power back
ON.
Is error code 6831 or 6834
still displayed?
Check the remote controller for
main-sub setting.
Is there only 1 remote
controller set as the main
controller?
Conduct the remote controller diagno-
sis twice or more times.
Is "OK" displayed on all
remote controllers?
Turn the power back ON.
Does "Please Wait"
disappear within 6 minutes?
Continue to the next page.
Note:
• It takes 6 seconds at maximum until the result is displayed.
OCH790 _74
No
Yes
No
Yes
No
Yes
Yes
No
Yes
Causes and checkpoints
• Contact failure of remote controller wiring
• Irregular wiring
(A wiring length, number of connecting remote control-
lers or indoor units, or a wiring thickness does not meet
the conditions specified in the chapter "Electrical Work"
in the indoor unit Installation Manual.)
• Malfunction of the remote controller sending/receiving
circuit in the indoor unit with the LED2 blinking.
• Malfunction of the remote controller sending/receiving
circuit
• Remote controller transmitting error caused by noise
interference
Is "NG" displayed?
No
Yes
Is "6832" or "ERC"
Yes
displayed?
No
No abnormality
A connector or wiring contact failure is
suspected.
Set 1 remote controller to main remote
controller, and the other to sub.
No abnormality
It might be caused by an external noise, so
check the transmission line.
Replace the remote controller.
Replace the indoor controller board with the
LED2 blinking.
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