F05 High
Your boiler has detected a problem with how it disposes of waste gases, often caused by a blockage or a fault in the air flow system.
Technical description: Air pressure switch contact error – wrong flue baffle obstructed or not correctly sized
Typical repair cost: £120-280 (including labour)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Protect yourself from future repair bills
A boiler cover plan would cover faults like F05 — no call-out fees, no surprises.
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Parts commonly replaced
- Air pressure switch
- Flue fan
- Venturi tube
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