Daikin Altherma HT Service Manual

Troubleshooting by Indication on the Remote Controller ESIE09-08B
202 Troubleshooting
3.57 “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
Be sure to turn off power switch before connect or disconnect
connector, or parts damage may be occured.
Replace indoor unit PC
board
Correct the wiring
YES
NO
Is the wiring
("1-2-3" communication
and upwiring)
normal?

Daikin Altherma HT Specifications

General

Type	Air-to-water heat pump
Refrigerant	R-410A
Water Outlet Temperature	Up to 80°C
Operating Temperature Range	-20°C to 35°C
Power Supply	3-phase, 400V
Energy Efficiency Class (Heating)	A++