What to check, in order
- Turn the boiler off and bleed the radiators
Let the air out of each radiator.
- Check the pressure
After bleeding, make sure it still reads 1 to 1.5 bar, and top it up if it has dropped. Then turn the boiler back on.
- L3 only: check the yellow gas valve
Ideal also says to check the yellow gas isolation valve under the boiler is on: the handle points in the direction of the pipe.
- Reset the boiler
Press the reset button.
When to call a Gas Safe engineer
If it comes back, the central heating pump may not be running. Contact your installer, or Ideal, quoting the code: it needs an engineer visit.
Good to know
- Ideal suggests gently touching the pump to tell if it's running: it should vibrate gently and feel warm. Only do this if the pump is outside the boiler. Never take the boiler's cover off.
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.
- Radiator bleed keySearch on Amazon
Affiliate links: as an Amazon Associate I earn from qualifying purchases, at no extra cost to you. It never changes a verdict.
Quick answers
What does the Ideal FD fault code mean?
Water isn't flowing through the boiler as it should, so it has stopped. Ideal's fault list also gives L3 for no water flow.
Can I fix Ideal FD myself?
Easy (about 30 minutes). Start with: turn the boiler off and bleed the radiators; check the pressure; L3 only: check the yellow gas valve. If it comes back, the central heating pump may not be running. Contact your installer, or Ideal, quoting the code: it needs an engineer visit.
Is Ideal FD worth repairing?
Worth fixing. Air in the radiators costs nothing to let out. If the pump has stopped, it's an engineer's job.
Checked against
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.