BoilerFaultCodesThe 6 most common faults
Your boiler has detected that a vital safety switch is stuck in the 'on' position, preventing the system from starting its safety checks.
Why it happens: This fault occurs when the boiler's internal safety sensor thinks the fan is already running before the start sequence has even begun. The most common reason is a mechanical failure within the air pressure switch where the internal contact has become stuck, or moisture has built up in the narrow sensing tubes. Because the boiler cannot verify that the fan is starting correctly from a 'zero' state, it shuts down for safety.
Full guide for Neon1Your boiler is failing to start because the internal fan is not spinning correctly or the control board cannot confirm it is working.
Why it happens: This fault occurs when the boiler's control board sends power to the fan but does not receive the necessary electrical feedback to confirm it is spinning safely. The most common reasons are a seized fan motor due to age, a perished vacuum tube, or a failing computer board that can no longer process the fan's signal.
Full guide for Neon2Your boiler has lost power to its main control board, which means the system cannot operate or provide heating and hot water.
Why it happens: This fault occurs when the link between the boiler's external controls and its internal brain is broken, preventing electricity from reaching the main control board. The most common reason is a component failure on the board itself or a blown internal fuse, which acts as a safety measure if there has been an electrical surge. In some cases, loose or damaged wiring between the components can also stop the power flow.
Full guide for Neon3Your boiler is currently trying to light the burner and you are seeing the normal indicator for the ignition spark.
Why it happens: This indicator appears when the control board sends an electrical current to the ignition electrode to create a spark. It is a normal part of the starting process where the boiler attempts to light the gas to begin heating your home. If the light continues to flash without the boiler firing up, it usually means the spark is occurring but the gas is failing to ignite or the system cannot 'see' the flame.
Observe the light during start-upExpect the light to stop flashing once the flame is establishedNo action is required as this is normal operation
Your boiler has automatically turned off because it got too hot, acting as a safety precaution to prevent damage.
Full guide for Boiler Overheat ThermostatYour boiler has lost the water pressure it needs to circulate heat, likely due to a slow leak somewhere in your radiators or pipes.
Full guide for Loss of system water pressureon the Ideal Classic FF 330
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 Ideal 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