BoilerFaultCodesTechnical description
Overheat cut off device tripped or thermostat, overheat cut off device faulty.
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety switch to trip and shut the system down to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of sludge and scale that blocks the flow through the heat exchanger.
This issue often surfaces during the first cold spell of autumn when the heating is turned back on after being idle all summer, which can cause the pump to seize.
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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