BoilerFaultCodesYour boiler has sensed that the exhaust gases are getting too hot and 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: High flue thermostat temperature
What causes this fault?
This fault occurs when the internal safety sensors detect that the waste gases leaving your boiler have reached an unsafely high temperature. The most common reasons are a build-up of debris or limescale inside the main heat exchanger, or a physical blockage that is preventing the heat from being transferred correctly into your central heating water.
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 3 — 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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