BoilerFaultCodesTechnical description
Overheat - High temperature limit thermostat tripped
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety switch to shut the system down. The most common reasons are a pump failure that stops water from moving or a blockage in the main heat exchanger that prevents heat from transferring correctly.
This fault is more frequent when you first turn the heating back on in Autumn, as pumps can seize up after being inactive over 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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