Heat pumps · Error codes · Riello
58Riello · NXHP (R290 monobloc)
58 on a Riello NXHP: Compressor envelope protection - low SST in heating
Short answer
On a Riello heat pump, 58 means: Compressor envelope protection - low SST in heating. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Compressor envelope protection - low SST in heating.
Likely causes:
- Manual: investigations and corrective actions to be performed by a fully qualified technician (see Table 6 probable causes).
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
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.
- Restart once via the controller (OFF then ON) as the manual allows; if the code returns, call an engineer.
What the engineer will check
- Manual: investigations and corrective actions to be performed by a fully qualified technician (see Table 6 probable causes).
Sources
- Riello NXHP Series Installation, Operation and Maintenance Instructions (ManualsLib copy) ↗ · not stated · page 67 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026