High Lockout
A2 on Worcester Bosch WR325 RSF

Your boiler has detected an issue with the air supply or the way it releases exhaust gases, preventing 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

Ventilation

What causes this fault?

This fault occurs when the boiler's internal safety sensors detect that the fan isn't moving enough air to safely clear exhaust gases from the system. The most common reasons are a blockage in the flue pipe, a worn-out fan motor, or a failure in the switch that monitors air pressure.

This fault can sometimes be triggered during periods of very high winds, which can create back-pressure in the flue and interfere with the air pressure readings.

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

C1View →C6View →A5View →

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