BoilerFaultCodesThe 6 most common faults
Your boiler is not receiving the gas it needs to light, meaning it cannot provide heating or hot water.
Why it happens: This fault occurs when the boiler's internal safety sensors detect that a flame hasn't been established after several attempts to light. The most common reasons are a lack of gas reaching the unit, a faulty component failing to create a spark, or the gas valve not opening correctly to allow fuel into the burner.
Check if your gas emergency control valve is turned on.If you have a prepayment meter, check that you have enough credit.Try lighting another gas appliance, like a hob, to see if the gas supply is active.
Your boiler is struggling to light because the small pipe that starts the main flame is clogged with dust or debris.
Why it happens: This fault occurs when the tiny hole that allows gas to reach the pilot light becomes restricted by a buildup of household dust or soot. Because the pilot flame cannot stay strong enough to heat the safety sensor, the boiler fails to ignite the main burner as a security precaution.
Full guide for A(3)Your boiler is struggling to stay lit because the small starter flame is being blocked by a buildup of soot or debris.
Why it happens: This fault occurs when the small tube that delivers gas to the starter flame becomes restricted by tiny particles of soot or dust. Without a strong enough pilot flame to heat the safety sensor, the boiler will automatically shut down to prevent gas from leaking into the room. The most common reason is simply a buildup of debris over many years of operation which eventually chokes the gas supply to the burner.
Full guide for A(4)Your boiler is unable to create the spark needed to light the flame, which means your heating and hot water will not work.
Why it happens: This fault occurs when the boiler's internal computer sends a signal to start the fire, but no spark is physically generated to ignite the gas. The most common reason is that the electronic ignition component has failed or the spark electrode has become worn or cracked over time. Without this initial spark, the boiler cannot light safely and will shut down to prevent unburnt gas from building up.
Full guide for A(5)Your boiler is unable to create the spark needed to light the gas because the ignition part or its wiring is faulty.
Why it happens: This fault occurs when the boiler's ignition system fails to generate the electrical arc needed to light the burner. It is usually caused by the metal electrode becoming worn and cracked over time, or the high-tension lead suffering from heat damage which prevents the spark from reaching the gas.
Full guide for A(6)Your boiler's pilot light is likely going out because a safety sensor has lost its connection, preventing the unit from staying lit.
Why it happens: This fault occurs when the safety sensor that detects the pilot light fails to send a clear signal back to the main gas valve. The most common reason is that the physical connection between the thermocouple and the control box has vibrated loose or become corroded over time. Because the boiler can no longer verify that a flame is present, it shuts off the gas supply as a safety precaution.
Full guide for B(2)on the Potterton Flamingo RS40 RS50
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