BoilerFaultCodesThe 6 most common faults
Your boiler is failing to light the fuel or keep the burner running, meaning it is not producing any heat or hot water.
Why it happens: This fault occurs when the boiler attempts to light the burner but cannot detect a stable flame. The most common reasons include a worn-out sensor that can no longer 'see' the fire, a blockage in the gas supply, or an electronic failure that prevents the initial spark from occurring.
Check if your gas supply is active by testing another gas appliance like a hobEnsure your credit meter has sufficient fundsPress the reset button on the front of the boiler for a few seconds
Your boiler has switched itself off because it has detected that the water inside has become or is at risk of becoming too hot.
Why it happens: This fault occurs when the water temperature inside the boiler exceeds a safe limit, triggering a safety shut-off to protect the internal components. It is most commonly caused by a circulation problem, such as a failing pump or a blockage, which prevents the heated water from leaving the boiler quickly enough.
Check that your radiator valves are open and not blocked by furniture.Ensure there is enough water pressure by checking the gauge is between 1 and 1.5 bar.Turn the selector switch to the reset position for five seconds and then back to the original setting.
Your boiler is struggling to circulate water, most likely because the system pressure has dropped too low or the internal pump is stuck.
Why it happens: This fault occurs when the boiler detects that water isn't moving through the heat exchanger fast enough to safely carry heat away. The most common reason is that the system pressure has dropped too low for the pump to work, or the pump itself has seized after a period of inactivity.
Locate the pressure gauge on the front of the boilerIf the needle is below 1 bar, use the filling loop valves underneath the boiler to top it up to 1.5 barTurn the selector switch to the reset position for five seconds and then back to the heating/hot water mode
Your boiler has detected that water is not circulating correctly through the system, preventing it from firing up to heat your home or water.
Why it happens: This fault occurs when the boiler's internal sensors do not detect enough water movement to operate safely, usually because the pump has failed or the flow switch is stuck. The most common reason is that the rubber diaphragm inside the flow valve has perished or the pump has become seized after a period of inactivity.
Check that the central heating valves under the boiler are fully openEnsure all radiator valves are turned on and not stuckCheck the boiler pressure gauge and top it up to 1.5 bar if it is too low
Your boiler is lighting but cannot detect that the flame has been lit, causing it to shut down shortly after for safety.
Why it happens: This fault occurs when the boiler's internal sensors fail to confirm that a flame is present, even if you can see it lighting briefly. The most common reason is a worn-out sensing probe that has become covered in carbon soot or a faulty control board that is no longer 'listening' for the flame signal. For safety, the boiler shuts down immediately because it thinks it is leaking unburnt gas.
Check that your gas supply is turned on and other gas appliances are workingRotate the selector switch to the 'Reset' position for five seconds and then back to the heating/hot water iconEnsure the system pressure is between 1 and 1.5 bar on the pressure gauge
Your boiler has detected a system error or internal failure that is preventing it from starting up correctly.
Why it happens: This fault occurs when the boiler's internal computer, the Printed Circuit Board, suffers an electrical failure or loses communication with its sensors and switches. The most common reason is age-related wear to the board's components or loose connections in the wiring that prevent the boiler from performing its safety checks.
Turn the selector switch to the 'Reset' position and hold for at least 5 secondsReturn the switch to the heating or hot water positionCheck that your gas pre-payment meter (if applicable) has credit
on the Potterton Performa 28i
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