Heat pumps · Error codes · Riello
E1Riello · NXHM (R32 monobloc)
E1 on a Riello NXHM: Phase loss or neutral wire and live wire are connected reversely (only for three phase unit)
Short answer
On a Riello heat pump, E1 means: Phase loss or neutral wire and live wire are connected reversely (only for three phase unit). The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Phase loss or neutral wire and live wire are connected reversely (only for three phase unit).
Likely causes:
- Power supply cables not secure (phase loss).
- neutral and live connected reversely.
Is it safe?
Switch the heat pump off at its isolator and call an engineer.
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
What you can check
- Read and note the exact code shown on the controller display.
- Check the heat pump's breaker/isolator at the consumer unit is on.
- If the breaker has tripped or trips again, leave the unit off and call an engineer; do not keep resetting it.
What the engineer will check
- Power supply cables not secure (phase loss).
- neutral and live connected reversely.
Sources
- Riello NXHM Installation and Owner's Manual (IT/EN), cod. 20192830 rev. 0 07/2021 ↗ · 20192830 rev. 0 · page PDF 66 (printed 138) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026