A 18 Emergency

Vokera A 18 Fault Code

Also written as A18 — same fault.

The Vokera A 18 fault code means: your boiler is struggling to confirm that the flame has turned off properly after it finished its heating cycle, which is a safety mechanism to prevent gas buildup.. It appears on 1 Vokera model in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: The flame was still detected after more than 10 seconds from the closure of the gas valve. Press the reset key. If the error is permanent replace the circuit board.
Typical repair cost £250-450 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Vokera models that show the A 18 fault code

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

Source

Vokera A 18 fault code information on this page is sourced and cross-checked against the official Vokera service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026