BoilerFaultCodesThe 6 most common faults
Your boiler has detected a problem with how it disposes of waste gases or condensation, causing it to shut down for safety.
Check the white plastic condensate pipe outside for visible ice or blockages; if frozen, gently defrost with warm (not boiling) water.Inspect the flue terminal on the outside wall to ensure it isn't obstructed by debris, leaves, or bird nests.Reset the boiler by turning the selector switch to the 'R' position for five seconds.
Your boiler has switched itself off because it has detected that the water inside has become too hot.
Check that your radiator valves are open and not turned to the off positionEnsure the boiler pressure is between 1 and 1.5 bar on the pressure gaugeWait for the boiler to cool down and then press the 'Reset' button
Your boiler has detected that the water pressure is too low for it to operate safely and has shut down as a precaution.
Locate the external filling loop, which is usually a silver flexible hose underneath or near the boiler.Slowly open the one or two valves on the filling loop to allow water into the system.Monitor the pressure gauge on the boiler until it reaches between 1.0 and 1.5 bar, then close the valves tightly.Reset the boiler using the selector switch if the fault code does not clear automatically.
Your boiler is struggling to move water correctly through the system, which is causing it to shut down to prevent overheating.
Check that your boiler pressure is between 1.0 and 1.5 bar on the gauge.Ensure all radiator valves and external isolation valves are fully open.Gently bleed your radiators to remove any trapped air pockets.
Your boiler has failed to light because either gas is not reaching the burner or the flame is not being detected.
Check that your gas emergency control valve and any appliance isolation valves are openIf you have a pre-payment meter, verify that you have credit availableCheck if other gas appliances in your home, such as a hob, are working correctlyPress and hold the 'Reset' button for five seconds to restart the boiler ignition sequence
Your boiler has sensed that water is not circulating properly before the burner ignites, often due to trapped air or a blockage.
Check that all radiator valves and boiler isolation valves are fully openGently bleed your radiators to remove any trapped airEnsure the system pressure is between 1.0 and 1.5 bar on the pressure gauge
on the Potterton Promax System ErP
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