BoilerFaultCodesYour boiler has detected an issue with how exhaust gases are being cleared from the system, causing it to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue thermostat / flue pressure switch tripped
What causes this fault?
This fault occurs when the boiler's safety sensors detect that harmful exhaust fumes are not being effectively cleared through the flue pipe to the outside. The most common reasons are a buildup of debris in the internal air tubes, a failing fan that cannot push the gases out, or a physical blockage in the flue itself.
This fault can be more common during periods of high winds, which can create back-pressure in the flue and cause the pressure switch to trip.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like E03 — no call-out fees, no surprises.
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