Ideal F10 fault codewhat it means and how to fix it
The spark generator on a Logic Combi2 — the unit that makes the ignition spark — has failed a self-check. Ideal's instruction is to check its wiring and, if that is sound, replace it.
Take care
Get a Gas Safe registered engineer to look at your Ideal F10
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
What F10 means
F 10 is Spark Generator Fault, one of the codes the 2023 three-character Logic boards added so that an ignition problem could be pinned to a part rather than reported as a bare lockout. The spark generator is a small high-voltage transformer that turns the board's low-voltage command into the spark at the electrode; the electrode is the visible part at the burner, the generator is the box it is wired to.
Earlier Logic boards could only tell you the boiler had failed to light — L2 — and left the engineer to work through electrode, harness, generator and gas valve in Ideal's ignition chart. The Combi2 board monitors the generator circuit and calls out this fault on its own. Ideal's remedy is one line in the installation manual: check wiring, if OK replace spark generator. There is nothing in the user guide for it, and nothing a householder can usefully do beyond one press of Restart.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Generator wiring or connector | Ideal put the wiring first. The generator's supply lead and the HT lead to the electrode both live in a hot, vibrating space and a connector that has worked loose gives an intermittent fault. | Common |
| Spark generator failed | The transformer has an open or shorted winding. Ideal's remedy after the wiring check is simply to replace it, and it is not an expensive part. | Common |
| Board output fault | Not in Ideal's one-line remedy for this code, but the same circuit appears in their ignition lockout chart, where a board that cannot drive the generator is the last thing checked. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£90–£200
Time on site
45 minutes
A spark generator fitted £90–£160; a little more if the electrode and lead are changed at the same time.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Ideal Logic ignition electrode
175565£18–£42Authorised Ideal parts distributor
Price checked 28 September 2026
Ideal Logic spark generator
£35–£80Authorised Ideal parts distributor
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Ideal fault codes
- L2Stop — call an engineerThe boiler failed to detect a flame during ignition and has locked out on the gas valve. Do not keep resetting it.Related: ignition and gas supply
- F2Get it checkedThe flame was lost during operation. Ideal direct you to check the gas supply first, and that is genuinely the right order.Related: ignition and gas supply
- LCUsually simple to fixYou have reset the appliance five times in fifteen minutes. This is not a fault in itself — it is the boiler asking you to stop.Related: ignition and gas supply
- L FStop — call an engineerAn Isar, Icos, Mexico HE or Esprit has made three attempts to light and locked out; the LED window flashes L then F. Ideal permit one reset and a gas supply check, then an engineer.Related: ignition and gas supply
- L6Stop — call an engineerA flame is being detected when there should not be one. Turn the appliance off and call a Gas Safe engineer rather than resetting it.Related: ignition and gas supply
- F16Stop — call an engineerThe board has detected a fault in the gas valve or its wiring. Nothing here is for a householder to try; Ideal's checks cover the valve's supply and coil and end with replacing it.Related: ignition and gas supply
Own an Ideal boiler? Save it and its codes come first next time.
Related guides
Common questions about Ideal F10
Is this the same as an ignition lockout?
It is one specific cause of one. On a Combi2 you might see F 10 on its own, or L 02 after the boiler has tried to light without a working spark. Either way the engineer goes to the generator first, which is the point of the code.
Does an older Logic have this code?
No. The ESP1 and earlier boards report ignition failure as L2 and leave the diagnosis to the engineer's chart. F 10 belongs to the Logic Combi2, System2 and Heat2 and the i-mini2 from 2023.
Could I have smelled gas with this fault?
You should not have. The gas valve only opens once a spark is being generated and closes again within seconds if no flame is detected, so a dead spark generator means no gas rather than unburnt gas. If you can smell gas at all, that is a separate emergency: leave, and call 0800 111 999.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.