BoilerFaultCodesTechnical description
Safety temperature limiter has operated
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, forcing the system to shut down to prevent damage. The most common reasons are a pump failure that stops water from moving around the system or a build-up of debris causing a blockage in the heat exchanger.
This issue is more frequent during the autumn when heating is turned back on after a long summer break, as internal components like the pump can seize from lack of use.
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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