BoilerFaultCodesYour boiler has detected an issue with the air supply or the way it releases exhaust gases, preventing it from firing up safely.
Book a Gas Safe engineer within 24–48 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 fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like A2 — no call-out fees, no surprises.
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Worcester Bosch WR325 RSF is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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