4 Red Flashes High
Your boiler has detected an issue with the ventilation fan, which means it cannot safely clear exhaust fumes and will not ignite.
Technical description: Fan Fault
Typical repair cost: £220-450 (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 4 Red Flashes — no call-out fees, no surprises.
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Parts commonly replaced
- Extractor Fan
- Fan Wiring Harness
- Printed Circuit Board (PCB)
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