High
F.37 on Vaillant ecoTEC plus Aquaplus

Your boiler has detected that the internal fan responsible for moving air is not spinning at the correct speed, which prevents it from firing up safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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

The rotary speed of the fan is too high or too low | Air pressure switch defect; fan defect; electronics defect

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F.32View →F.61View →F.62View →

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