BoilerFaultCodesYour boiler has shut down because it has reached an unsafe temperature and needs to cool down before it can operate again.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Temperature limiter has responded.
What causes this fault?
This fault occurs when the water inside the heat exchanger gets too hot, triggering a safety sensor to shut the system down to prevent damage. The most common reasons are a failed pump that isn't moving water through the boiler or a blockage in the pipework that is restricting flow. It can also be caused by air trapped in the system or a faulty sensor providing an incorrect temperature reading.
This fault is more frequent when the heating is first turned on after summer, as pump components can seize up after long periods of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to the off positionEnsure there is enough water pressure in the system by checking the pressure gaugeWait 20 minutes for the unit to cool and try pressing the reset button
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 F2 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Viessmann Vitodens 100 Compact 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.