High Lockout
AL34 on Vokera Mynute Vhe

Your boiler has stopped working because it cannot correctly detect the speed of the fan responsible for clearing exhaust gases.

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

Fan tacho signal fault

What causes this fault?

This fault occurs when the boiler's main computer loses track of how fast the internal fan is spinning, which is a vital safety check before the burner can ignite. The most common reason is a communication failure caused by worn-out bearings in the fan motor or a loose electrical connection in the wiring. Without an accurate speed reading, the boiler shuts down to prevent dangerous exhaust gases from building up inside the unit.

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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