BoilerFaultCodesYour boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, and it has shut down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue thermistor fault
What causes this fault?
This fault occurs when the internal sensor responsible for monitoring the temperature of the waste gases becomes faulty or loses its connection to the main control board. The most common reason is that the sensor has physically failed due to high heat exposure over time, or the electrical wiring connecting it has become loose or damaged. Because this sensor prevents the boiler from overheating and damaging the flue, the system shuts down immediately for safety.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like E28 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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