BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because it either cannot detect a flame to heat the water or the internal drainage pipe for waste water is blocked.
Why it happens: This fault happens when the boiler attempts to light but fails to detect a stable flame, often because the electrodes are worn or the gas supply is restricted. It can also be triggered if the internal waste water pipe becomes backed up with debris or liquid, which prevents the combustion process from starting safely. In both cases, the boiler shuts down as a safety precaution to prevent unburnt gas from building up.
Check if other gas appliances in your home are working to ensure your gas supply is active.Inspect the white plastic pipe (condensate pipe) leading outside to see if it is frozen or blocked.Turn the control knob to the 'R' (Reset) position for five seconds and then back to the 'On' position.
Your boiler has switched itself off because it is getting too hot inside, likely due to a circulation problem or a sensor fault.
Why it happens: This fault occurs when the boiler's internal temperature exceeds a safe limit, triggering a safety switch to prevent damage. It is usually caused by water failing to move around the system quickly enough to carry heat away, often due to a pump failure or a blockage. In some cases, the sensor itself may have failed and is reporting a high temperature even if the boiler is cool.
Check that all radiator valves are fully openEnsure your system pressure is between 1.0 and 1.5 bar on the gaugeTurn the selector switch to 'Reset' for five seconds and then back to the original position
Your boiler has detected that there is not enough water pressure or the pump isn't circulating water through the system properly.
Why it happens: This fault occurs when the boiler's internal sensors detect that water isn't moving through the heat exchanger as it should, which can cause the unit to overheat. The most common reasons are that the water pressure has dropped too low for the system to operate, or the internal pump has seized or failed. Occasionally, a large air bubble trapped inside the pipework can also block the flow and trigger this error.
Check the pressure gauge on the front of the boiler; it should ideally be between 1 and 1.5 bar.If the pressure is too low, use the filling loop valves underneath the boiler to top it up slowly.Bleed any trapped air from your radiators and then re-check the pressure gauge.
Your boiler has detected that water isn't moving through the system correctly, which has caused it to stop working to prevent overheating.
Why it happens: This fault occurs when the boiler's internal sensors detect that water isn't circulating through the heat exchanger, causing a safety shutdown to prevent internal damage. The most common reason is a lack of water pressure in the system, but it can also be caused by a mechanical failure in the pump or a perished rubber diaphragm that fails to trigger the flow switch.
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is too low, use the filling loop underneath the boiler to top it up.Bleed your radiators to remove any trapped air that might be blocking water flow.
Your boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Why it happens: This fault occurs when the water inside the boiler reaches an unsafe temperature or the exhaust gases become too hot, triggering a safety sensor to cut the power. The most common reasons are a pump failure preventing water from circulating or a blockage within the heat exchanger that traps heat inside the unit. It can also be caused by a build-up of air pockets or various faulty internal sensors failing to accurately read the temperature.
Check that your radiator valves are open and not turned to zero.Ensure there is enough water pressure indicated on the boiler's pressure gauge (typically 1 to 1.5 bar).Turn the selector switch to the 'Reset' position for five seconds, then turn it back to the 'On' position.
Your boiler has tried to light but either failed to start or cannot detect that a flame is present, often due to a lack of gas or a drainage issue.
Why it happens: This fault occurs when the control board fails to detect a stable flame after several attempts to ignite the burner. The most common reasons are a temporary interruption in the gas supply, a build-up of carbon on the internal sensors, or a blockage in the drainage pipe that prevents waste water from leaving the unit.
Check that your gas meter has credit and that the gas emergency control valve is open.Turn the selector switch to the 'Reset' position, hold for five seconds, then turn it back to the 'On' position.Check that the external condensate pipe is not frozen if it is winter.
on the Potterton Performa 24 Eco HE
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 Potterton 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