Daikin ERRQ 016AAY1 - U4 Malfunction of Transmission Indoor Unit

ESIE09-08 Troubleshooting by Indication on the Remote Controller
Troubleshooting 199
3.56 “U4” Malfunction of Transmission Indoor Unit
Remote Control
Display
U4
Subcode 4
Applicable
Models
AII indoor unit models
Method of
Malfunction
Detection
Microcomputer checks QA communication of indoor unit.
Malfunction
Decision
Conditions
When transmission is not carried out normally for a certain amount of time
Supposed
Causes
 Wrong wiring between indoor unit PC boards. [A4P (1ø) or A5P (3ø)] and A1P
Troubleshooting
Caution
Replace indoor unit PC
board
Correct the wiring
YES
NO
Is the wiring
("1-2-3" communication
and upwiring)
normal?
Be sure to turn off power switch before connecting or disconnecting connector,
otherwise parts may be damaged.