Ideal F14 fault codewhat it means and how to fix it
The mains voltage reaching a Logic Combi2 is too high for the board to run on. It is the mirror image of F7, and Ideal's instruction is the same: contact your electricity provider.
Take care
What F14 means
F 14 is High Mains Voltage, and only the 2023 three-character Logic boards report it; older Logics watch for a supply that is too low and say nothing about one that is too high. UK mains is nominally 230 volts with a permitted band up to about 253, and electronics in a boiler are built to that band. Above it the board protects itself, its pump and its fan by refusing to run, and it reports F 14 rather than a mysterious lockout.
Ideal's remedy is four words, contact electricity provider, because a supply that is too high is not something a heating engineer can adjust. The condition can be intermittent — a street transformer tapped high, or a lightly loaded rural line in the small hours — and it can arise in a house with solar panels, where an inverter exporting into a weak grid pushes the local voltage up on sunny afternoons.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Network supply running high | The transformer feeding the street is set at the top of its band and the load is light. The boiler is the most sensitive appliance in the house and the first to notice. | Common |
| Solar inverter raising the local voltage | A PV system exporting on a bright day lifts the voltage at the consumer unit. A code that appears in sunshine and clears at dusk is this. Not something Ideal write about; it follows from how an exporting inverter behaves on a weak grid, and it is this page's inference rather than anything an electrician has confirmed for it. | Occasional |
| Fault in the property's supply | A neutral fault on a shared supply can send voltage well over 253 volts on one side of the house and low on the other. Other appliances will be complaining too. | Rare |
What to try yourself
Note when it happens — time of day, weather, whether other things in the house behave oddly at the same time. Then ring your electricity network operator on 105; they can log the supply at your meter and it is their fault to fix, at no charge.
If you have solar panels, tell the network operator and your installer both. An inverter set to the wrong grid limits can be adjusted; a grid that cannot take the export is the network's to sort out.
Get a Gas Safe registered engineer to look at your Ideal F14
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 it costs to fix
Typical repair cost
£0–£120
Time on site
20 minutes
Nothing if the network operator resolves the supply. An electrician's visit to confirm the reading £80–£120.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Ideal fault codes
- F9Get it checkedThe control board has not been told what boiler it is in, or has failed. L9 is the same fault locked out. The 2011 Logic Combi row also covers a gas valve short circuit.Related: electronics and power
- dUUsually simple to fixNot a fault. The diverter valve has been parked in its mid-position for servicing and the boiler is waiting to be told the service is over. Ideal publish the way out.Related: electronics and power
- Blank displayGet it checkedNothing on the screen at all. Ideal's user guides send you to the boiler's switch and the consumer unit first; the installer charts then work from the terminal block to the board.Related: electronics and power
- F7Get it checkedThe mains voltage reaching the boiler has dropped below what the board will run on. Ideal's advice is an electrician or your electricity supplier, not a heating engineer.Related: electronics and power
- C0Get it checkedThe board cannot activate the Boiler Chip Card that tells it what model it is fitted to. Ideal's engineer check is whether the small plastic card is in its slot at all.Related: electronics and power
- L9Get it checkedOn a Logic, L9 is the locked-out form of the unconfigured-board fault F9. On an Isar HE it is something else entirely: a heat exchanger overheat read by the dry-fire thermistor.Related: electronics and power
Own an Ideal boiler? Save it and its codes come first next time.
Related guides
Common questions about Ideal F14
Is my boiler damaged?
The code exists so that it is not. The board stops before the voltage reaches a level that would hurt the pump or fan, and an F code clears itself once the supply comes back into range.
Why did my old Logic never show this?
Because it could not. The ESP1 and earlier boards have F7 for low voltage and no high-voltage code; a supply running high on those boards shortened component life quietly instead. F 14 is a Combi2, System2, Heat2 and i-mini2 code only.
Should I call a heating engineer for F 14?
Not first. Ideal's only remedy for this code is to contact the electricity provider, and a Gas Safe engineer has no way to lower the voltage arriving at your meter. Call the network operator on 105; involve an electrician only if they find the supply at the meter is fine and the problem is inside the house.
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.