U4-00 - Indoor/Outdoor Unit Communication Problem - Daikin Perfera ARXM25A Service Manual

3.5.30 U4-00 – Indoor/outdoor unit communication problem
RXM20~50A + ARXM25~50A + FTXM20~50A + ATXM20~50A + CTXM15A
Split Perfera ZETA R32
ESIE23-06 – 2023.12
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
circuit" [ 4 51].
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 Perform a check of the power supply, connections, wiring,... between the
outdoor unit and the indoor unit. See
Possible cause: Faulty wiring between the outdoor unit and the indoor unit.
3 Perform a check of the main PCB. See Main PCB.
Possible cause: Faulty main PCB.
4 Perform a check of the outdoor unit fan motor. See Outdoor unit fan motor.
Possible cause: Faulty outdoor unit fan motor.
5 Perform a check of the indoor unit main PCB. See Indoor unit PCB.
Possible cause: Faulty indoor unit main PCB.
6 Perform a check of the indoor unit power PCB. See Indoor unit power PCB.
Possible cause: Faulty indoor unit power PCB.
Prerequisite: Stop the unit operation via the user interface.
Prerequisite: Turn OFF the respective circuit breaker.
7 Wait until the rectifier voltage is below 10 V DC.
DANGER: RISK OF ELECTROCUTION
Wait for at least 10 minutes after the circuit breaker has been turned OFF, to be sure
the rectifier voltage is below 10 V DC before proceeding.
8 Check that the thermal interface grease is applied properly on the (PCB or
refrigerant piping) contact surface of the heat sink. Adjust if needed.
Possible cause: Thermal interface grease NOT applied properly on the heat
sink.
Effect
Unit will stop operating.
"4.1 Electrical
draft – 21/12/2023 13:09
3 | Troubleshooting
Reset
Power reset via outdoor
unit.
"4.1 Electrical
circuit" [ 4 51].
Service manual
37