3 P9 Low

Ariston 3 P9 Fault Code

Also written as 3P9 — same fault.

The Ariston 3 P9 fault code means: your boiler has reached its pre-set service interval and is simply reminding you that it is time for a routine professional safety check.. It appears on 5 Ariston models in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Sched.Maintanace-Call Service
Typical repair cost £90-130 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Ariston models that show the 3 P9 fault code

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

Source

Ariston 3 P9 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 7 July 2026