E15 Low

Ariston E15 Fault Code

The Ariston E15 fault code means: your boiler has lost its connection to the outside temperature sensor, which helps it run more efficiently based on the weather.. It appears on 2 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: Outdoor sensor open circuit (where fitted)
Typical repair cost £70-130 (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 E15 fault code

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

Source

Ariston E15 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