E33 High

Ariston E33 Fault Code

The Ariston E33 fault code means: your boiler's internal extraction fan is running when it shouldn't be, which is a safety lockout to prevent the appliance from operating incorrectly.. It appears on 3 Ariston models 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: Fan operation sensed with no demand for central heating or domestic hot water
Typical repair cost £150-£300 (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 E33 fault code

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

Source

Ariston E33 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 31 August 2026