Heat pumps · Error codes · Riello
PdRiello · NXHM (R32 monobloc)
Pd on a Riello NXHM: High temperature protection of refrigerant outlet temp of condenser
Short answer
On a Riello heat pump, Pd means: High temperature protection of refrigerant outlet temp of condenser. 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: High temperature protection of refrigerant outlet temp of condenser.
Likely causes:
- Coil cover not removed.
- dirty/blocked coil.
- insufficient space around unit.
- fan motor broken.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| 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.
- Check the outdoor unit is not blocked by leaves, debris or snow and has clear space around it.
- Restart once via the controller (OFF then ON) as the manual allows; if the code returns, call an engineer.
What the engineer will check
- Coil cover not removed.
- dirty/blocked coil.
- insufficient space around unit.
- fan motor broken.
Sources
- Riello NXHM Installation and Owner's Manual (IT/EN), cod. 20192830 rev. 0 07/2021 ↗ · 20192830 rev. 0 · page PDF 67 (printed 139) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026