Daikin RY24PEV1K Service Manual page 104

 Malfunction display: E6 Communications Failure
communication line between indoor and
two ends of communication line are separately
MAINTENANCE
Malfunction of communication
Yes
Check if
indoor unit's communication line is
properly connected
Yes
Check if
communication line is closed circuit
Yes
Check if the
indoor units is properly
connected
Yes
Check if the
equipped with ferrite cores
Yes
Check if the connected
outdoor unit is energized
Yes
Replace the controller
No
Confirm the locations of
plug and socket
No
Replace the communication
line
No
Confirm the locations of
plug and socket
No
Equip the ferrite cores
No
Energize the outdoor unit
SiK401004_A
96