BoilerFaultCodesYour boiler has switched itself off because it has become too hot to operate safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches a dangerously high temperature, triggering a safety shut-off to prevent damage. The most common reasons include a failing pump that isn't moving water away fast enough, or a buildup of debris and sludge that is restricting the flow through the system.
This issue is more frequent during the first cold spell of autumn when the heating is turned on after a long summer break, as internal parts like the pump can seize from lack of use.
DIY fix possible
Check that your radiator valves are open to allow water to flow.Wait for the boiler to cool down completely.Press the reset button once to see if the system restarts.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like Steady light — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch 14/19cbi is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.