Riello NXHM fault E6

Ambient temperature sensor (T4) error

Heat pump

What it means

Fault with the ambient temperature sensor T4.

Likely causes

  1. T4 sensor connector loosened
  2. T4 sensor connector wet or has water ingress
  3. T4 sensor failure

Where to start

  1. Check if T4 sensor connector is loosened
  2. Check if connector is wet or has water in it

The full answer, free

  • How to put it right, step by step
  • The manual page for this fault (page 66), right under the answer

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.

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