Vokera E011 Fault Code: Causes, Fixes & Repair Costs
What does the Vokera E011 fault code mean?
The E011 code means your Vokera boiler has detected flame activity at a point in its operating cycle when no flame should be present. This is the opposite of a typical ignition failure — rather than failing to light, the boiler's safety system believes a flame is burning when it shouldn't be. As a result, the boiler locks out entirely to prevent unsafe combustion or a gas-related hazard. This is a genuine safety lockout and should be treated seriously: one reset attempt is reasonable, but if the code returns, the boiler should not be used until a Gas Safe registered engineer has inspected it.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Faulty or contaminated flame sensor Common
The flame sensor (also called an ionisation probe) monitors whether the burner is alight. Over time it can become coated with combustion residue or simply degrade, causing it to report a flame signal even when the burner is not firing. This is the most frequently identified root cause of E011 on Vokera appliances.
- Gas valve not closing fully Sometimes
If the gas valve sticks in a partially open position, a small amount of gas can continue to reach the burner after the boiler has tried to shut down. The flame sensor then correctly detects residual combustion — which the control system registers as an unexpected flame. A valve that won't seal reliably is both a cause of E011 and a safety concern in its own right.
- Wiring faults affecting the flame detection circuit Sometimes
Loose terminals, damaged insulation, or moisture ingress on the cables linking the flame sensor to the PCB can introduce stray electrical signals that mimic a genuine flame reading. Wiring issues are worth ruling out before replacing more expensive components.
- PCB (printed circuit board) fault Rare
The PCB is the boiler's central controller. If it develops a fault — whether from age, a voltage spike, or component failure — it may misinterpret sensor signals or fail to correctly sequence the gas valve and ignition system, generating a spurious E011 lockout.
How to fix it
- Note the fault code displayed on the boiler DIY safe
Before doing anything else, confirm the screen shows E011 and make a note of it. If a Gas Safe engineer visits later, having the exact code recorded helps them diagnose the fault more quickly.
- Attempt a single boiler reset DIY safe
Follow your Vokera boiler's reset procedure (typically hold the reset button for a few seconds until the lockout clears). Allow the boiler to complete a full start-up cycle and observe whether it runs normally. Do not reset more than once — repeated resets on a combustion-safety fault can mask a genuine hazard and risk further damage.
- Check for obvious external signs before calling an engineer DIY safe
Listen for unusual clicking, hissing, or rumbling noises. Note whether you can smell gas (if you can, leave the property, avoid operating switches, and call the National Gas Emergency Service on 0800 111 999 immediately). Do not remove the boiler casing or touch any internal components.
- If the fault returns, stop using the boiler and call a Gas Safe registered engineer Gas Safe engineer
A recurring E011 indicates an underlying fault with the flame sensor, gas valve, wiring, or PCB — none of which are safe or legal for a homeowner to work on. An engineer will carry out a combustion analysis, test the ionisation circuit, inspect the gas valve for leakage, check all relevant wiring, and assess the PCB. They will advise on which component needs replacing and carry out the work safely.
- Engineer to test and replace the flame sensor if required Gas Safe engineer
The engineer will remove, clean, and electrically test the ionisation probe. If it is out of specification it will be replaced with a Vokera-compatible part and the boiler re-tested for correct flame detection before being returned to service.
- Engineer to inspect and replace the gas valve if required Gas Safe engineer
The engineer will check whether the gas valve closes fully and seats correctly. A valve that leaks past its seat must be replaced — this work involves the gas supply and must only be carried out by a Gas Safe registered engineer.
- Engineer to inspect wiring and, if necessary, assess the PCB Gas Safe engineer
All connectors on the flame-detection circuit will be checked for corrosion, looseness, and damage. If wiring is sound and other components test correctly, the PCB will be evaluated. PCB replacement is a last resort given the cost involved, particularly on older Vokera models.
Parts you may need
- Vokera ionisation / flame sensor probe · from £35
- Vokera gas valve · from £120
- Vokera PCB (model-specific) · from £200
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £150–£400, depending on the underlying cause.
Frequently asked questions
Is the Vokera E011 fault dangerous?
E011 is a safety lockout triggered because the boiler has detected a flame at the wrong point in its cycle. The boiler shuts itself down deliberately to prevent unsafe combustion, so the immediate risk is managed. However, the underlying cause — most often a faulty flame sensor or a gas valve that isn't closing properly — does need professional attention. If you smell gas at any point, treat it as an emergency: leave the building and call the National Gas Emergency Service on 0800 111 999.
Can I keep resetting my Vokera boiler to clear the E011 code?
One reset is reasonable and is unlikely to cause harm. Repeatedly resetting the boiler is not advisable, though. E011 is a combustion-safety fault, and resetting without addressing the root cause can hide a genuine problem and potentially lead to unsafe operation. If the fault returns after a single reset, switch the boiler off and arrange for a Gas Safe engineer to inspect it.
How much does it typically cost to fix a Vokera E011 fault in the UK?
Most homeowners pay somewhere between £150 and £400 all-in, depending on which part is at fault. A flame sensor replacement (the most common fix) usually falls at the lower end of that range. A gas valve replacement tends to sit in the middle. If the PCB is the culprit, costs can rise to £400–£500 or more, since the board itself is expensive. On an older Vokera boiler, it's worth getting an engineer's opinion on whether repair or replacement of the whole appliance makes more financial sense before committing to a costly PCB.
Is the E011 fault covered under my Vokera warranty?
It may be, particularly if your boiler is relatively new. Check your warranty documentation or contact Vokera directly to confirm coverage and whether an approved engineer is required to carry out the repair. Using a non-approved contractor can sometimes void warranty terms, so it is worth checking before you book anyone in.