BoilerFaultCodesThe 6 most common faults
Your boiler has switched itself off because the internal water temperature has become too hot, usually caused by a lack of water flow through the system.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature, causing the system to shut down for safety. The most common reasons are a pump failure preventing water from moving through the system or a blockage caused by a build-up of sludge and debris. It can also be triggered by a faulty sensor that is incorrectly reporting the water temperature to the control board.
Check that your radiator valves are fully openEnsure your boiler pressure is between 1 and 1.5 bar on the gaugeReset the boiler by turning the control knob to 'RE' or pressing the reset button
Your boiler has tried to light several times but cannot establish a flame, meaning it has shut down for safety to prevent gas build-up.
Why it happens: This fault occurs when the boiler's control system attempts to start a flame but fails to detect one after several tries. It is often caused by a lack of gas reaching the burner, a dirty or damaged ignition spark, or a sensor that can no longer 'see' the flame even if it has lit. In some cases, a blocked flue or internal component failure prevents the correct mix of air and gas required for ignition.
Check if your gas supply is active by testing another gas appliance like a hob.If you have a prepay meter, ensure you have sufficient credit.In freezing temperatures, check if the external condensate pipe has frozen.Reset the boiler by turning the mode knob to 'RE' and back to your desired setting.
Your boiler has lost its flame while trying to run, which means it cannot heat your water or your radiators.
Why it happens: This fault occurs when the boiler's control board detects that the flame has gone out unexpectedly while the unit is firing. The most common reasons are a restricted gas supply, a build-up of carbon on the ignition sensors, or a faulty gas valve failing to maintain the correct flow of fuel.
Check that your gas supply is turned on at the meterIf you have a prepay meter, check that you have enough creditPress the Reset button on the boiler displayEnsure your external condensate pipe hasn't frozen in very cold weather
Your boiler has lost its flame while running, meaning it is not getting enough gas or the spark is failing to keep the burner lit.
Why it happens: This fault occurs when the boiler successfully starts but then unexpectedly loses its flame while it is trying to provide heat or hot water. The most common reasons are a dirty or worn-out sensor that can no longer 'see' the flame, or an inconsistent gas supply that causes the burner to go out. It can also be caused by debris blocking the burner or a failing component that manages the electrical spark.
Check if your gas meter has credit (if on a prepayment meter)Check if other gas appliances, like a hob, are working to confirm gas supplyReset the boiler by turning the mode knob to 'RE' and then back to the desired settingEnsure the external condensate pipe has not frozen if it is winter
Your boiler has shut down because its internal temperature has become too high, often caused by a lack of water flow or a blockage.
Why it happens: This fault occurs when the water inside the boiler gets too hot, triggering a safety sensor to shut the system down to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of sludge and debris that creates a blockage in the pipework.
Check that your boiler pressure is between 1 and 1.5 bar on the gaugeEnsure all radiator valves and the isolation valves under the boiler are fully openPress the 'Restart' button on the front control panel
Your boiler has failed to light after several attempts, meaning it has shut down as a safety precaution and will not provide heating or hot water.
Why it happens: This fault occurs when the boiler tries to light itself several times but fails to detect a stable flame. The most common reasons are a lack of gas supply to the unit, a dirty ignition component that can no longer create a spark, or a debris-clogged burner.
Check if other gas appliances in your home, such as a gas hob, are working to ensure gas is reaching the property.Ensure your pre-payment gas meter has credit if applicable.Press the 'Reset' button on the boiler control panel once to see if it restarts. Only attempt this three times maximum.If it is freezing outside, check that your white plastic condensate pipe leading outdoors is not frozen and blocked.
on the Ideal Logic Max System
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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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