How much does it cost to fix Ariston error code E 20?

Typical repair cost for the Ariston E 20 fault is £150-300 including labour.

E 20 Emergency

Ariston E 20 Fault Code

Q: What does the Ariston E 20 fault code mean?

Your boiler is confused and thinks there is a flame inside while the gas supply is already switched off, which has caused it to shut down for safety.

Also written as E20 — same fault.

The Ariston E 20 fault code means: your boiler is confused and thinks there is a flame inside while the gas supply is already switched off, which has caused it to shut down for safety.. It appears on 4 Ariston models in our database.

Technical description: False flame detection with gas valve closed

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 E 20 fault code

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

Source

Ariston E 20 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