U4" Malfunction Of Transmission Indoor Unit - Daikin ALTHERMA HT Service Manual

Troubleshooting by Indication on the Remote Controller
3.57 "U4 " Malfunction of Transmission Indoor Unit
U4
Remote Control
Display
Subcode 4
AII indoor unit models
Applicable
Models
Microcomputer checks QA communication of indoor unit.
Method of
Malfunction
Detection
When transmission is not carried out normally for a certain amount of time
Malfunction
Decision
Conditions
 Wrong wiring between indoor unit PC boards. [A4P (1
Supposed
Causes
Troubleshooting
202
Be sure to turn off power switch before connect or disconnect
connector, or parts damage may be occured.
Caution
Is the wiring
("1-2-3" communication
and upwiring)
normal?
YES
NO
Replace indoor unit PC
board
ø ø
) or A5P (3 )] and A1P
Correct the wiring
ESIE09-08B
Troubleshooting