Mitsubishi Electric PURY-P72 Service Handbook page 271

[ IX Troubleshooting ]
6833
1. Error Code
6833
MA remote controller signal transmission error (Hardware error)
2. Error definition and error detection method
ŒCommunication between the MA remote controller and the indoor unit is not done properly.
ŒAn error occurs when the transmitted data and the received data differ for 30 times in a row.
3. Cause
1) Contact failure of the remote controller lines of MA remote controller or the indoor unit
2) 2 or more remote controllers are set to MAIN
3) Overlapped indoor unit address
4) Noise interference on the remote controller lines
5) Failure to meet wiring regulations
ŒWire length
ŒWire size
ŒNumber of remote controllers
ŒNumber of indoor units
6) Problems with the circuit on the remote controller that sends or receives the signals from the remote controller
4. Check method and remedy
1) Check for disconnected or loose transmission lines for the indoor units or MA remote controllers.
2) Confirm that the power is supplied to the main power source and the remote controller line.
3) Confirm that MA remote controller's capacity limit is not exceeded.
4) Check the sub/main setting of the MA remote controllers.One of them must be set to MAIN.
5) Diagnose the remote controller (described in the remote controller installation manual).
[OK]: no problems with the remote controller (check the wiring regulations)
[NG]: Replace the MA remote controller.
[6832, 6833, ERC]: Due to noise interference <Go to 6)>
6) Check wave shape/noise on MA remote controller line by following "IX [3] Investigation of Transmission Wave Shape/
Noise".(page 286)
7) When no problems are found with items 1) through 6), replace the indoor unit board or the MA remote controller.
The following status can be confirmed on LED1 and 2 on the indoor unit board.
ŒIf LED1 is lit, the main power source of the indoor unit is turned on.
ŒIf LED2 is lit, the MA remote controller line is being powered.
HWE1116D - 262 - GB