BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because it failed to light properly or the waste water pipe is blocked.
Why it happens: This fault occurs when the boiler tries to light but cannot detect a stable flame, prompting the system to shut down for safety. The most common reasons are a lack of gas supply, a dirty sensing probe that can't 'see' the flame, or a blockage in the waste water pipe that causes water to back up into the heat exchanger. In many cases, it is simply a sign that the components responsible for the spark or flame monitoring have worn out.
Check that your gas pre-pay meter hasn't run out of credit.Inspect the white plastic pipe (condensate pipe) outside to see if it is frozen or blocked.Attempt to reset the boiler by turning the control knob to 'R' for five seconds.
Your boiler has shut down because its internal safety sensors detected that it was beginning to overheat.
Why it happens: This fault occurs when water inside the boiler reaches an unsafe temperature, triggering a safety switch to prevent damage. The most common reasons are a failed pump that isn't circulating water properly, or a buildup of sludge and limescale that blocks the heat exchanger. It can also be caused by a simple sensor failure where the boiler incorrectly thinks it is overheating.
Ensure all radiator valves are fully open to allow water to circulateCheck that the boiler pressure is between 1.0 and 1.5 bar on the gaugeAllow the boiler to cool down, then turn the selector switch to 'R' for five seconds to reset
Your boiler has stopped working because either there isn't enough water pressure in the system or the internal pump is unable to circulate water.
Why it happens: This fault occurs when the boiler detects that there is not enough water pressure or flow to safely operate the internal heat exchanger. The most common reasons are a simple drop in system pressure that needs topping up, or a mechanical failure of the internal pump which prevents water from moving around your radiators.
Check the pressure gauge on the front of the boiler; if it is below 1 bar, it needs topping up.Locate the filling loop (usually a silver flexible hose) underneath the boiler.Slowly open the valves until the pressure reaches 1.5 bar, then close them tightly.Reset the boiler to see if the fault clears.
Your boiler has got too hot and has automatically shut down to prevent damage.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety switch to kill the flame. The most common reasons are a pump failure preventing heat from being carried away or a build-up of sludge and debris blocking the internal pipework.
Ensure all radiator valves are fully open to allow water to circulate.Let the boiler cool down for 30 minutes.Turn the control knob to the 'Reset' position for five seconds, then turn it back to 'On'.
Your boiler has stopped working because it cannot light the flame or the internal drainage pipe is backed up with water.
Why it happens: This fault occurs when the boiler tries to light but fails to detect a steady flame, or when the internal drain for waste water becomes blocked. The most common reason is a buildup of debris in the condensate trap or a worn-out ignition spark causing a failed startup. If the waste pipe is blocked, the boiler shuts down as a safety precaution to prevent water from backing up into the combustion chamber.
Check if your gas prepay meter has credit and that the external gas stopcock is open.Inspect the plastic condensate pipe outside for signs of freezing or blockage; gently pour warm water over it if frozen.Turn the selector switch to the reset position for five seconds, then turn it back to the 'on' position.
Your boiler has shut itself down because it has detected that the water or the exhaust fumes have become too hot.
Why it happens: This fault occurs when the boiler's internal temperature exceeds safe limits, triggering a safety sensor to cut off the gas supply. The most common reasons are a failed pump stopping water from circulating or a build-up of limescale and sludge creating a blockage that traps heat inside the heat exchanger.
Check that your radiator valves are open and not turned to zeroTurn the control knob to the 'Reset' position for five seconds and then back to 'On'Ensure the boiler pressure gauge is between 1 and 1.5 bar
on the Potterton Performa System 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