Heat pumps · Error codes · Ariston
2P8Ariston · NIMBUS NET R32 control platform (shared error list)
2P8 on an Ariston NIMBUS NET R32 control platform: Low pressure warning
Short answer
On an Ariston heat pump, 2P8 means: Low pressure warning. The heat pump keeps running. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Low pressure warning.
Part involved: water pressure switch.
Likely causes:
- Water leakage in the hydraulic circuit.
- Faulty pressure switch / cabling.
Is it safe?
| Does the heat pump stop? | No |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running.
What you can check
- Check the system pressure gauge: the user manual says 0.5-1.5 bar when cold; if low, ask the installer (repeated top-ups indicate a leak or expansion-vessel problem).
- Note the error code shown on the Sensys HD interface and contact the installer / Ariston service.
What the engineer will check
- Check for water leaks.
- Check the pressure switch connection and replace if necessary.
Who to ask for: heat pump controls / hydronics.
Certification: Competent heating engineer; electrical competence for wiring checks.
What you might notice
Sources
- NIMBUS PLUS M NET R32 - Technical instructions for installation and maintenance (UK) - codes 3301719 3301720, doc 420000656201 EN ↗ · 420011311701 - 03/2024 · page 71 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026