BoilerFaultCodesThe 6 most common faults
Your boiler has become too hot and has automatically shut down as a safety precaution.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature, causing the system to shut down to prevent damage. The most common reasons are a pump failure that stops water from moving or a blockage in the heat exchanger that restricts flow. It can also be caused by a faulty internal sensor that is incorrectly reporting the temperature.
Wait at least 30 minutes for the boiler to cool down completely.Turn the main selector switch to the 'Reset' position and hold for 5 seconds.Turn the switch back to the 'On' position and check if the burner reignites.Ensure all radiator valves are open and the system pressure is between 1 and 1.5 bar.
Your boiler has tried to fire up but could not light the flame, causing it to shut down for safety.
Why it happens: This fault occurs when the boiler's internal sensor fails to detect a flame after several attempts to start. The most common reasons are a lack of gas reaching the burner, a faulty spark that cannot ignite the gas, or a sensor that is too dirty to see the flame that has been lit.
Check that your gas supply is turned on at the meterTurn the control knob to the 'Reset' position for five secondsSlowly release the knob back to the 'On' position and wait for the boiler to restart
Your boiler has sensed a temperature issue and has likely locked out to prevent overheating.
Why it happens: This fault occurs when the boiler's internal sensors detect that the water temperature has risen too quickly or exceeded safe limits. The most common reason is a lack of water circulation, often caused by a failing pump or a blockage in the system preventing heat from being moved away from the burner.
Turn the selector switch to the reset position for five seconds and then back to your desired settingCheck that your radiator valves are open and not blockedEnsure the system pressure on the gauge is between 1 and 1.5 bar
Your boiler has too much water inside it, which is causing the safety valve to leak or trigger to protect the system from bursting.
Why it happens: This fault occurs when there is too much water pressure in the system, often caused by the filling loop being left slightly open or a internal leak between the domestic hot water and central heating sides. It can also happen if the expansion vessel has lost its air charge, meaning there is no room for water to expand as it heats up. As a result, the pressure rises rapidly until it forces the safety valve to open and discharge water.
Check that the filling loop valves are fully closed and not letting in more water.Release excess pressure by bleeding a radiator into a container until the gauge reads between 1 and 1.5 bar.Check the discharge pipe outside for signs of leaking.If pressure continues to rise after bleeding, call a Gas Safe engineer to inspect the expansion vessel.
Your boiler has stopped working because the water pressure in the system has dropped too low to operate safely.
Why it happens: This fault occurs when there isn't enough water circulating inside your heating system to safely transfer heat, triggering a safety sensor to shut the boiler down. The most common reasons are a slow leak from a radiator valve or pipework, or the pressure relief valve becoming faulty and letting water escape the system.
Locate the silver filling loop underneath the boilerSlowly open both taps/levers on the filling loop until you hear water movingClose both taps tightly once the pressure gauge on the front of the boiler reaches between 1.0 and 1.5 bar
Your boiler has attempted to light but has failed to detect a flame, causing it to shut down for safety.
Why it happens: This fault occurs when the boiler's internal sensors cannot confirm that a flame has successfully ignited after several attempts. The most common reasons are worn-out ignition sparks that fail to light the gas, or a dirty sensor that cannot 'see' the flame even if it is actually burning. It can also be caused by an interruption in the gas supply or a fault within the main control board.
Check if other gas appliances in your home, such as a hob, are working to confirm gas supply.Verify that your gas meter has credit if you use a top-up or pre-payment system.Press and hold the reset button for five seconds to see if the boiler restarts.
on the Potterton Performa 24
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