What to check, in order
- Check your gas credit
If your gas meter is pay-as-you-go, make sure there's credit on it.
- Try another gas appliance
If other gas appliances in your home don't work either, Ideal says to contact a local gas engineer.
- Check the yellow gas valve
It's the yellow gas isolation valve under the boiler. When it's on, the handle points in the direction of the pipe.
- In freezing weather, thaw the condensate pipe
Hold a hot water bottle or a microwavable heat pad around it, or pour tepid water over the frozen part.
- Reset the boiler
Press the restart button. On some boilers it's sunk into the panel and you press it with the end of a pen: your user guide shows where.
When to call a Gas Safe engineer
If it still locks out, call Ideal quoting L2, or a Gas Safe registered engineer. If the boiler gurgles as it tries to light, contact your installer: Ideal says there may be a blockage.
Good to know
- Ideal's fault list gives F2 the same meaning, with the same checks.
Parts people end up buying
Only if the checks above point to a part. Match it to your model number first: it's on a label on the data badge, usually under the boiler or behind the front cover.
- Condensate pipe laggingSearch on Amazon
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Checked against
- Ideal Heating: what does my boiler fault code mean
- Ideal Heating: how to defrost a frozen condensate pipe
- Ideal Heating: why is my boiler not working
Last reviewed September 2026. Manufacturers update their pages, and your manual is the final word.