Ideal Logic fault codes- What they mean, and who can fix them

Author: Michael
7th October 2022
5 min read

Unfortunately, even well-maintained boilers can experience issues and breakdown.  Not ‘ideal’ is it!  There are many working components within a boiler and if something was to go wrong with them, the boiler will display a fault code to let you know what the issue is.  This post will highlight the most common ideal Logic fault codes and if they can be fixed by you at home, or require a heating engineer’s expertise.


ideal Logic F1 fault – Low water pressure

The F1 fault code is displayed when the water pressure is low, causing the boiler to ‘lock out’, and stop working.  The boiler pressure should normally sit around 1.5 bar and you can check this by looking at your boilers pressure gauge.  It is normal for your boiler to lose pressure over time, however if you find that the pressure drops suddenly, there may be an underlying issue such as a leak somewhere on the heating system which would require investigation by a registered gas safe engineer.

The good news is that most of the time you can fix low pressure faults yourself by topping the pressure up using the boilers ‘filling loop’.  You can check out one of our previous articles Here which explains how to do this.

If you do not feel confident doing this yourself, then we would recommend asking a qualified Gas Safe engineer to resolve the issue for you.

ideal Logic F2 fault – Flame loss

The F2 fault code displayed on an ideal boiler means that the boiler is igniting, however something is causing the flame to cut out.  This can indicate there is either no gas supply or an insufficient supply to the boiler.  If you have other gas appliances in your property, first check to ensure they are receiving a gas supply and working properly and try resetting your boiler to see if it fires.

If your other gas appliances are not working, or  you don’t have any but have a prepayment gas meter, you should check to confirm there is sufficient credit on the meter.  If you do not have a prepayment meter, or there is available credit on the meter, then there may be an issue the fan, PCB (printed circuit board) or low gas pressure to the property.

Each of these issues would require investigation from an engineer.


ideal Logic F3 fault – Fan fault

Another one of the most common ideal Logic fault codes is the F3 fault code, this code indicates there is a fan related issue.  Try resetting the boiler to see if the fault code clears and the boiler fires.  If this doesn’t fix the issue, a Gas Safe engineer will be required.  If your boiler is still under warranty, it is worthwhile contacting ideal to arrange a warranty repair.

If Celsius installed your boiler and it’s still under warranty, then we will contact ideal on your behalf to arrange a fast-tracked visit as part of our Celsius Aftercare promise.


ideal Logic F4 fault – Thermistor fault

An F4 fault code on tends to indicate an issue with the boilers flow thermistor.  This is usually related to circulation issues and will require investigation from a Gas Safe engineer.


ideal Logic F9 fault – Printed Circuit Board (PCB) fault

Another of the common ideal Logic fault codes is the F9 fault code.  This usually points towards an unconfigured PCB.  This could occur if the PCB has not been installed correctly or it’s not sending and receiving signals properly.  Repairing this type of fault will require a Gas Safe engineer and could be expensive.  If your boiler is still under warranty, you can try contacting ideal to arrange a warranty repair.

If Celsius installed your boiler and it’s still under warranty, then we will contact ideal on your behalf to arrange a fast-tracked visit as part of our Celsius Aftercare promise.


ideal Logic L1 fault – Lack of water flow

The L1 Fault code is displayed when the temperature readings are too low or too high.  When this happens, the boiler will stop working.  You can try resetting your boiler to see if this resolves the issue, if not then you should contact a Gas Safe engineer.  The L1 fault usually only occurs with older boilers that are less efficient.  It may be worthwhile considering replacing your boiler, depending on its age.


ideal Logic L2 fault – Ignition lockout

An L2 fault code will display when something has caused the boiler to ‘lock out’ and stop working.  You can try to reset your boiler to fix the issue.  If you hear rumbling coming from the system, it means that the condensate is blocked or there is an issue with the flue.  This would require investigation from a Gas safe engineer.

If you are reading this during a period of cold weather it could be that your condensate pipe is frozen.



From time to time, as with all other boiler manufacturers, you may experience problems with ideal boilers.  Some of these problems you can fix yourself, others will require a suitably qualified Gas safe engineer to repair.

If you would like to arrange for one of our Celsius boiler heroes to attend and investigate/repair your boiler issue, find out more Here.  A member of the team will then get back to you.  Alternatively, you can give us a call on 0131 258 0848

If you are considering replacing your boiler- you can use our online Boiler Tool – just answer a few questions regarding your property and current heating system and you will then receive an instant quote. (Prices are subject to survey).


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