U7-00 - Outdoor Unit: Transmission Malfunction Between Main Microcomputer - Inverter Microcomputer; U8-02 - Connection With Room Thermostat Lost - Daikin Altherma 3 H HT ECH2O Service Manual

3.5.89 U7-00 – Outdoor unit: Transmission malfunction between main microcomputer - inverter
microcomputer
3.5.90 U8-02 – Connection with room thermostat lost
EPRA14~18D + ETSH/X(B)16P30+50E
Daikin Altherma 3 H HT ECH₂O
ESIE22-11A – 2023.06
Trigger
Communication
abnormality between
main and inverter
microcomputer.
To solve the error code
INFORMATION
It is recommended to perform the checks in the listed order.
1 Perform a check of the main PCB. See
Possible cause: Faulty main PCB.
2 Perform a check of the inverter PCB. See
Possible cause: Faulty inverter PCB.
INFORMATION
If all procedures listed above have been performed and the problem is still present,
contact the helpdesk.
Trigger
Communication
abnormality between unit
and room thermostat
after connection was
already made.
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" [ 361].
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 communication wiring between the remote controller and the unit.
See "4.24 User interface" [
Possible cause: Faulty wiring between the remote controller and the unit.
3 Perform a check of the room thermistor:
Effect
Unit will stop operating.
"4.16 Main
"4.13 Inverter
Effect
Unit will NOT stop
operating.
4
336].
3 Troubleshooting
|
Reset
Manual reset via user
interface.
4
PCB" [ 226].
4
PCB" [ 209].
Reset
Automatic reset.
"5.1 Electrical
Service manual
81