U4-00 - Indoor/Outdoor Unit Communication Problem - Daikin EBLA04E V Series Service Manual

3.3.78 U4-00 – Indoor/outdoor unit communication problem
EBLA04~08E + EDLA04~08E
Daikin Altherma 3 M
ESIE22-09 – 2022.05
To solve the error code
1 Check if the power supply is compliant with the regulations. See
4
circuit" [ 254].
Possible cause:
▪ Faulty or disturbance of the power supply (power supply MUST be within
range of nominal operating voltage ±4%),
▪ Power drop,
▪ Short circuit.
INFORMATION
If all procedures listed above have been performed and the problem is still present,
contact the helpdesk.
Trigger
Communication failure
between outdoor and
indoor unit.
To solve the error code
INFORMATION
It is recommended to perform the checks in the listed order.
1 Check if the power supply is compliant with the regulations. See
4
circuit" [ 254].
Possible cause:
▪ Faulty or disturbance of the power supply (power supply MUST be within
range of nominal operating voltage ±4%),
▪ Power drop,
▪ Short circuit.
2 Check the wiring between the hydro PCB and the main PCB. See
4
circuit" [ 254].
Possible cause: Faulty wiring between the hydro PCB and main PCB.
3 Perform a check of the main PCB. See
Possible cause: Faulty main PCB.
4 Perform a check of the outdoor unit fan motor. See
4
motor" [ 197].
Possible cause: Faulty outdoor unit fan motor.
5 Perform a check of the hydro PCB. See
Possible cause: Faulty hydro PCB.
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
6 Wait until the rectifier voltage is below 10 V DC.
Effect
Unit will stop operating.
"4.14 Main
"4.12 Hydro
draft – 31/05/2022 15:53
3 | Troubleshooting
"5.1 Electrical
Reset
Power reset via outdoor
unit.
"5.1 Electrical
"5.1 Electrical
4
PCB" [ 184].
"4.15 Outdoor unit fan
4
PCB" [ 175].
Service manual
71