BoilerFaultCodesThe 6 most common faults
Your boiler has switched itself off because the water inside the system has become too hot.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature limit because it isn't moving away from the heat exchanger properly. The most common reasons are a pump failure, a blockage caused by sludge and debris in the pipework, or air trapped within the system preventing flow.
Check that at least two or three radiator valves are fully open to allow water to flow.Ensure there are no obstructions or trapped air by bleeding your radiators.Check your boiler pressure gauge and top it up to 1.5 bar if it is too low.
Your boiler is trying to start up but cannot successfully light the gas to create a flame.
Why it happens: This fault occurs when the boiler's internal sensor fails to detect a flame after several attempts to ignite the gas. The most common reasons are a lack of gas supply to the unit, a worn-out ignition spark, or a buildup of debris on the internal probes that monitor the combustion process.
Check that your gas emergency control valve is in the 'on' positionIf you have a prepaid meter, ensure you have active credit and the meter is not lockedReset the boiler by pressing the reset button to see if it was a temporary glitch
Your boiler has shut down because it cannot breathe properly, likely due to a blockage in the pipes leading to the outside of your home.
Why it happens: This fault occurs when the boiler's internal sensors detect that it cannot safely pull in fresh air or expel exhaust gases. The most common reasons include an external blockage in the flue pipe, such as a bird's nest or debris, or a mechanical failure of the fan that prevents air from moving through the system.
Check the external flue terminal on your outside wall for obstructions like bird nests, leaves, or debris.During freezing weather, check if the flue outlet is blocked by ice or snow and gently clear it.Reset the boiler by pressing the reset button once any external obstructions are removed.
Your boiler has stopped working because one of its internal sensors is sending an incorrect signals or has disconnected, preventing it from heating your water safely.
Why it happens: This fault occurs when the boiler's control board loses communication with the sensors that monitor water temperature. It is usually caused by a physical break in the internal wiring or a sensor that has reached the end of its life and is sending unreadable data. Because the boiler can no longer confirm the water is at a safe temperature, it shuts down immediately as a safety precaution.
Full guide for F000Your boiler has shut down because the hot water has reached a temperature that is dangerously high.
Why it happens: This fault occurs when the water meant for your taps becomes dangerously overheated, triggering a safety shutdown to prevent scalding. The most common reason is that the boiler's internal sensors are giving incorrect readings, or the flow of water through the heat exchanger is being restricted by limescale or a mechanical failure. In some cases, a faulty valve may be sending heat to the wrong place, causing the temperature to spike rapidly.
Full guide for F002Your boiler has shut down because the internal gases leaving the system have become too hot, which is a safety feature to prevent damage to the internal components.
Why it happens: This fault occurs when the internal safety sensor detects that the exhaust gases have reached a dangerously high temperature, often due to a lack of water flow or a build-up of debris inside the heat exchanger. It essentially means the heat being produced isn't being carried away into your radiators efficiently enough, causing the internal components to overheat. In some cases, it can also be triggered by a faulty sensor providing an incorrect reading or damaged internal insulation.
Full guide for F003on the Intergas Xtreme / Xclusive
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Intergas shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue