EE0099 High

Ariston EE0099 Fault Code

The Ariston EE0099 fault code means: your boiler's sensor that monitors water returning from your radiators is malfunctioning, which is causing the system to stop heating your home as a safety precaution.. It appears on 1 Ariston model in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Heating return temperature probe short circuited
Typical repair cost £120-220 (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 EE0099 fault code

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

Source

Ariston EE0099 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