BoilerFaultCodesYour boiler has likely overheated because the gases exiting the system are too hot, causing a safety sensor to automatically shut it down.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue gas temperature limiter has triggered.
What causes this fault?
This fault occurs when the internal safety sensor detects that the exhaust gases are reaching dangerously high temperatures, which can damage the boiler's internal components. The most common reasons for this are a build-up of debris or limescale inside the heat exchanger blocking heat transfer, or a lack of water flow preventing the system from cooling down properly.
This issue often comes to light during the first cold snap of winter when the boiler is suddenly required to run at full power for several hours to heat a cold house.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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