Fault Codes Don’t Have to be Scary

Your boiler displaying a fault code you don’t recognise can be scary, especially when you’re reaching for your thermostat in October for the first time in months. The last thing you need at this time of year is your central heating system sending shivers down your spine — Halloween is already scary enough! 

Take a deep breath though, because there’s no need to fear. We’re here to answer some of your most frequently asked questions about boiler problems and fault codes, putting an end to your concerns!

What does L5 mean on an Ideal boiler screen?

This code means there’s a problem with the return. To reset this, turn your boiler off at the wall (fused spur) for a couple of seconds then switch it back on again.

What does status 'C' mean on an Ideal boiler screen?

'C' means the boiler has a central heating demand. This can be resolved by pressing reset on the front of the boiler — it won’t require turning the boiler off at the wall.

What does central heating demand mean?

Central heating demand simply means that your home’s central heating system is signalling to the boiler that water needs to be heated to power your radiators. This is most likely as a result of your thermostat being switched on, either manually or on a timer setting.

What does status 'D' mean on an Ideal boiler screen?

'D' means that the boiler is fired up for a hot water demand. Like ‘C’, this can be resolved by pressing reset on the front of the boiler and doesn’t require you to turn the boiler off at the wall.

What does it mean when '0' displays on my Ideal boiler screen?

'00' or ‘0’, depending on your Logic model, informs you that the boiler is in standby and not receiving a demand from either the hot water or central heating. If you receive this fault code, try running a tap or turning the heating on to see if the status changes.

What does ‘L2’ mean on an Ideal boiler screen?

The ‘L2’ means your boiler has lost its flame. This can happen for a variety of reasons, including that your gas pressure has dropped too low or that the flue has a blockage.

If you have a pay-as-you-go gas meter and accidentally run out of gas, you may see this code displayed on your boiler. If this happens, please top the gas up at any local store that supports gas top ups. 

Next, turn the power off on the boiler and then switch it on again. Restarting the boiler should clear the fault code. If this doesn’t work, it means you need to purge the gas into the boiler by repeating, turning the boiler off and on, then resetting the boiler every five minutes. 

This may take a while to purge the gas into the boiler.

What does ‘L2 – Ignition Lockout’ mean on an Ideal boiler screen?

If you have a ‘L2 – Ignition Lockout’ code on your boiler during the winter period, it’s important to check that a frozen condensate pipe is not causing the problem. 

At Ideal, we have created a video demonstration showing how to safely defrost a frozen condensate pipe.

What does fault code ‘FA’ flashing on an Ideal Logic Combi 35 mean?

This means there is an issue with the flow and return pipes are reversed. Although this is usually not the case on a combi boiler, if it does occur then there are some steps you can take. Check all isolation valves underneath the boiler are in the open position, all radiator valves are turned on full and the bypass is free flowing to see if this rectifies the issue.

If none of the checks and fixes above solve the problem, or if you discover that there is something wrong, don’t try to fix the issue yourself. Call a Gas Safe engineer to look over your boiler to find and fix any issues.


For a comprehensive list of fault codes, read our status code guide.

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