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Riello NXHM fault HA

Outlet water temp. sensor (Tw_out) fault

Heat pump

What it means

Fault with the outlet water temperature sensor Tw_out.

Likely causes

  1. Tw_out sensor connector loosened
  2. Tw_out sensor connector wet or has water ingress
  3. Tw_out sensor failure
  4. Rapid temperature change during initial heating of underfloor heating screed

Where to start

  1. Check if Tw_out sensor connector is loosened
  2. Check if connector is wet or has water in it
  3. At home page, go to MENU > OPERATION PARAMETER, press OK

The full answer, free

  • 2 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 65), right under the answer
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Safety: Isolate the heat pump 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 Riello manual for the NXHM. Check the model on the data plate before you order parts.

Other Riello NXHM fault codes