b 65 High

Vokera b 65 Fault Code

Also written as B65 — same fault.

The Vokera b 65 fault code means: your boiler is failing to start because it cannot detect that the fan is moving fast enough to clear out exhaust gases safely.. It appears on 1 Vokera 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: Insufficient fan speed for ignition

What causes the Vokera b 65 fault?

This fault occurs when the boiler's control system detects that the fan is not reaching the required speed to safely vent exhaust gases. The most common reasons are a build-up of debris within the fan assembly, a failing motor, or a blockage in the small plastic tubes that monitor air pressure. Without the fan spinning at full strength, the boiler will refuse to ignite as a safety precaution.

This fault is slightly more common in autumn and winter, as spiders or debris can block the pressure sensing tubes during periods of high wind or inactivity.

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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Vokera models that show the b 65 fault code

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

Source

Vokera b 65 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 27 April 2026