BoilerFaultCodesAriston 1 P2 Fault Code
Also written as 1P2 — same fault.
The Ariston 1 P2 fault code means: your boiler is struggling to move enough water through your heating system, which usually means there is a blockage, air trapped in the pipes, or a pump struggling to work.. It appears on 14 Ariston models in our database.
Technical description: Insufficient circulation indication
DIY fix possible
Check all radiator valves are fully open.Ensure your system pressure is set correctly between 1.0 and 1.5 bar.Bleed all radiators in the house to release any trapped air.
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Gas Safe Register →Ariston models that show the 1 P2 fault code
Click a model for the full fault code list and model-specific repair notes.
- Challenger 80E Repair: £120-250
- Clas HE 24 Repair: £100-250
- Clas HE 28 Repair: £100-250
- Clas HE 35 Repair: £100-250
- Clas HE Evo Repair: £120-250
- Clas Net One Repair: £120-250
- Clas One Repair: £120-250
- Clas System 28 Repair: £90-250
- E-Combi Evo Repair: £150-350
- E-Combi One Repair: £120-250
- E-Combi One 24 Repair: £120-£350
- E-Combi One 30 Repair: £120-250
- Egis Repair: £120-250
- Microsystem 15 Repair: £120-250
Source
Ariston 1 P2 fault code information on this page is sourced and cross-checked against the official Ariston service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026