BoilerFaultCodesTechnical 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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