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 - The water temperature has exceeded 95°C. This is a manual reset fault. To reset, wait for the boiler to cool down, then press and hold the 'R' button for 2 seconds.
What causes this fault?
This fault occurs when the water inside the boiler gets too hot because it isn't moving away from the heat exchanger fast enough. The most common reasons are a pump that has stopped working, a blockage in the pipework, or a build-up of air preventing water flow.
This issue is more frequent during the first cold snap of autumn when a pump that has been sitting idle all summer becomes stuck or 'seized'.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulate.Wait for the boiler to cool down for at least 20 minutes.Press and hold the 'R' button for 2 seconds to reset the system.
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 A — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Potterton Envoy Plus 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.