3P9 Low

Ariston 3P9 Fault Code

The Ariston 3P9 fault code means: your boiler is simply reminding you that its annual safety check and service are now due.. It appears on 6 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: Scheduled maintenance — call service
Typical repair cost £80-£120 (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 3P9 fault code

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

Source

Ariston 3P9 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