This fault can involve incomplete combustion and carbon monoxide.
If anyone in the property feels sick, dizzy or drowsy, or you can smell gas: open the windows, leave the building, and do not switch anything on or off. Then call the National Gas Emergency Service.
0800 111 999Vokèra A11 fault codewhat it means and how to fix it
The appliance is detecting a flame when there should not be one. Turn it off at the fused spur and get a Gas Safe engineer out.
Stop — this needs an engineer
Get a Gas Safe registered engineer to look at your Vokèra A11
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 A11 means
A11 is a false flame, sometimes described as an extraneous flame signal. The control board is reading a flame signal at a point in the cycle when the gas valve is supposed to be shut and the burner extinguished. There are two possible explanations and they are not equally serious. The benign one is that the sensing circuit is faulty and reporting a flame that does not exist — a contaminated electrode, moisture across a connector, or a degraded amplifier on the board.
The serious one is that the reading is accurate and gas is still burning after the valve was commanded closed, which means the gas valve is passing. That is a genuine gas safety fault. Because the appliance cannot tell you which of the two it is, and because you cannot tell from outside the casing either, the correct response is to treat it as the serious one until an engineer has proved otherwise.
Do not keep resetting it to get heat. One thing in Vokèra's own documentation is worth knowing before you see it happen: they classify A11 as a temporary alarm with no action listed against it, which means the appliance is designed to clear the code itself and carry on. That is a statement about how the control board handles the signal, not a verdict on the gas side, and a boiler that has gone back to working is not evidence the valve is sound.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Contaminated or shorting sensing electrode | Deposit or moisture provides a conduction path that mimics a flame signal. Benign in itself, and the more common of the two. | Common |
| Gas valve passing | The valve is not sealing fully when closed, so a small amount of gas continues to reach the burner. This is the reason the code is treated as urgent. | Occasional |
| Damp in the electrode lead or connector | Water tracking across a connector after a leak inside the case, or condensation in a cold garage installation. | Occasional |
| Control board flame amplifier fault | The board misreads its own input. Diagnosed once the gas side has been proved sound. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£110–£380
An electrode replacement is £110 to £190 fitted. A gas valve is £240 to £320. Expect a diagnostic charge on top if the two have to be separated with a flue gas analyser.
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 Vokèra fault codes
- A01Get it checkedThe burner failed to light and the appliance has locked out. Check the gas supply and, in cold weather, the condensate pipe before calling anyone.Related: ignition and gas supply
- A04Usually simple to fixSystem water pressure is below the minimum the appliance will run at. Topping the system back up to 1.2 bar normally clears it straight away.Related: same brand
- A02Get it checkedThe safety limit thermostat has tripped on overheat. In practice this nearly always means water has stopped circulating properly.Related: same brand
- A03Get it checkedThe appliance cannot confirm the fan is running correctly, so it will not permit the burner to light. This needs an engineer.Related: same brand
- A09Get it checkedThe flue gas sensor has recorded a temperature above the safe limit, or the sensor itself has failed. Either way the appliance stops.Related: same brand
- A07Get it checkedThe primary flow sensor is reading out of range or has failed. The appliance stops because it can no longer tell how hot it is running.Related: same brand
Own a Vokèra boiler? Save it and its codes come first next time.
Related guides
Common questions about Vokèra A11
The reset button is right there. Why should I not use it?
Because on a Vokèra the reset is easy to reach and this is the single code where reaching for it is the wrong move. Every other A code is asking to be reset once. This one is the appliance reporting a flame it cannot account for, and clearing that is the only thing you can do from the front panel that makes the situation worse. Isolate it electrically and leave it isolated.
I rent. What should I be doing today?
Report it to the landlord or agent in writing today rather than tomorrow, and use the words "the boiler is showing a false flame fault" so it is not triaged as a no-heating call. Landlords have a legal duty to maintain gas appliances. While you are writing, say whether the property has a working carbon monoxide alarm — in England, Scotland and Wales one is required in any room with a fuel-burning appliance, and if there is not one, that belongs in the same message.
My Vokèra shows E011 rather than A11. Is that the same fault?
Yes. The Vision Plus renumbers the whole set and gives this one as E011, "extraneous flame". The current Easi-heat i keeps the number and uses the same wording, A11 extraneous flame. Different label, same condition, same answer.
I am renting and my landlord says to just keep resetting it. Is that reasonable?
No, and you are entitled to push back. Gas appliances in rented property must be maintained by a Gas Safe registered engineer and checked annually. If you cannot get it dealt with, the Gas Safe Register and your local authority environmental health team can both advise.
How long can we go without heating while this is sorted?
Not indefinitely, but a night or two is a fair trade against the alternative. Use electric heaters in the meantime and keep pressing for the repair rather than accepting a reset as the fix.
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
- Trade body guidance
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.