BoilerFaultCodesTechnical description
Safety switch-off: Flue gas temperature too high
What causes this fault?
This fault occurs when the internal temperature of the exhaust gases exceeds safe limits, triggering a safety sensor to prevent damage or fire. The most common reason is a buildup of debris or limescale inside the heat exchanger, which prevents heat from being transferred to your water and instead pushes it out through the flue. It can also be caused by a faulty sensor sending incorrect readings or a lack of proper water flow through the system.
Engineer required
This is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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