E53 High
Your boiler is struggling to breathe properly because the exhaust pipe outside might be blocked or the gas is not burning correctly, causing the system to shut down for safety.
Technical description: Poor combustion – flue terminal may be blocked
Typical repair cost: £100-250 (including labour)
DIY fix possible
Check the external flue terminal (the exhaust pipe on your outside wall) for obstructions like bird nests, leaves, or debris.Carefully remove any visible blockages from the end of the pipe.Reset the boiler by turning the selector switch to 'R' for at least five seconds.
Protect yourself from future repair bills
A boiler cover plan would cover faults like E53 — no call-out fees, no surprises.
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Parts commonly replaced
- Flue seals
- Gas valve
- PCB
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