BoilerFaultCodesTechnical description
Limit thermostat fault
What causes this fault?
This fault occurs when the temperature inside the boiler exceeds a safe limit, causing a safety sensor to trip and shut the system down. The most common reasons are a pump failure that prevents hot water from moving away from the burner, or a build-up of sludge and limescale that restricts flow through the heat exchanger.
This fault is frequently seen when the heating is first turned back on in autumn, as pump components can seize up after being idle during the summer months.
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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