3P9 Low

Ariston 3P9 Fault Code

The Ariston 3P9 fault code means: your boiler has detected that it is time for a scheduled routine maintenance service to ensure it continues running safely and efficiently.. It appears on 1 Ariston model 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: E-combi oneE-System oneClas Net one CombiClas one CombiClas System one
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 27 April 2026