1p3 Medium

Ariston 1p3 Fault Code

Also written as 1P3 — same fault.

The Ariston 1p3 fault code means: your boiler is struggling to circulate water properly, which is causing it to overheat and shut down temporarily for safety.. It appears on 1 Ariston model in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: All Boilers
Typical repair cost £100-£350 (including labour)

DIY fix possible

Check that your boiler pressure is between 1 and 1.5 bar on the display.Ensure all radiator valves are fully open to allow water to flow.Gently bleed your radiators to remove any trapped air pockets.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Ariston models that show the 1p3 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Ariston 1p3 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