TradeAssistIQHome

Daikin Altherma fault U8-01

Connection with LAN adapter lost

Heat pump

What it means

Communication abnormality between unit and LAN adapter. Unit will NOT stop operating.

Likely causes

  1. Faulty LAN adapter PCB
  2. Faulty hydro PCB
  3. LD1 not flashing: no operation of LAN adapter
  4. LD2 flashing: TCP/IP communication problem with router
  5. LD3 flashing: communication problem between LAN adapter and indoor unit
  6. Communication error between bizone PCB and current loop PCB

Where to start

  1. Perform a check of the LAN adapter PCB
  2. Perform a check of the hydro PCB
  3. Observe LD4 LED state on the LAN adapter PCB

The full answer, free

  • 9 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 61), right under the answer
Ask about U8-01 freeCreate a free account

Safety: Isolate the outdoor unit and any backup heater, and give the inverter capacitors time to discharge before you open the electrics. Anything on the refrigerant circuit needs F-gas certification.

From the Daikin manual for the Altherma. Check the model on the data plate before you order parts.

Other Daikin Altherma fault codes