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Baxi E111 Fault Code: What It Means and What to Do
If your Baxi boiler is showing E111, it has detected that the fan is not running at the correct speed and has shut itself down as a safety measure. Because the fan controls the supply of combustion air and the removal of flue gases, this is a safety-critical fault. Here is what it means, what causes it, and where the homeowner line stops and a Gas Safe registered engineer begins.
Quick answer
E111 on a Baxi means the boiler has detected an incorrect fan speed and locked out to keep combustion safe — usually a faulty fan, its wiring or control board, or a flue affected by strong wind or a blockage. You can safely try a single reset and check that nothing obvious is blocking the flue outlet outside, but if the code returns it needs a Gas Safe registered engineer.
Do not open the boiler casing or touch the fan, flue, gas or any sealed parts. A repeating E111 points to a combustion-related fault that only a qualified engineer may legally diagnose and repair.
What does E111 mean on a Baxi boiler?
E111 is a safety lockout that appears when your Baxi boiler senses the fan is not spinning at the speed the control board (PCB) expects. The fan draws in air for combustion and pushes the products of combustion out through the flue, so the boiler constantly monitors its speed.
If the reading is wrong, the boiler shuts the burner down rather than risk burning gas without the correct airflow, and it displays the code.
On newer Baxi controls the same fault may appear in a longer format such as E.01.111, and the exact wording can vary a little across Baxi's model ranges (Duo-tec, Megaflo, EcoBlue, Platinum and so on), so your installation manual is the definitive reference.
In practice, though, E111 points to a fan-speed problem — the fan itself, its wiring or control, or something disturbing the flue. It should not be confused with the separate E110 overheat code, which is about the water getting too hot rather than the fan.
An occasional reset is fine, but a repeating E111 is a real fault — not something to keep clearing. Each lockout is the boiler protecting against unsafe combustion. If the code keeps coming back, stop resetting and book a Gas Safe registered engineer.
Common causes of E111
Most E111 lockouts come down to the fan or the conditions around the flue. Typical causes include:
- A worn or failing fan — bearings or the motor wearing out so the fan cannot reach or hold the correct speed.
- Wiring or electrical connection faults — a loose, corroded or damaged connector between the fan and the PCB.
- Strong wind or external draught over the flue — severe weather can disturb airflow enough to upset the fan-speed reading, sometimes as a one-off.
- A blocked or obstructed flue — debris, nests or a build-up at the flue terminal restricting airflow.
- A faulty PCB — the control board may be misreading the fan signal or failing to drive the fan correctly.
- A defective gas/air control or sensing fault — less common, but the boiler may report a fan-speed error when air-side sensing is wrong.
What you can safely check
E111 is an engineer-only fault, so there is no DIY repair here. There are, however, a few universal, no-tools checks any homeowner can safely make before calling out an engineer:
- Reset the boiler once. Follow the reset procedure in your manual (see our guide on how to reset your boiler). If E111 clears and does not return, it may have been a transient reading caused by weather. If it comes straight back, do not keep resetting.
- Look at the flue outlet from outside. From ground level only, check the external flue terminal is not obviously blocked by leaves, a nest, snow or debris. Do not touch the flue, climb to reach it, or poke anything into it — just look.
- Consider the weather. If there are very high winds, a single lockout may simply be a draught disturbing the fan. Reset once and see whether it settles when conditions ease.
- Confirm the gas is on. Check other gas appliances are working, in case the supply has been interrupted.
That is the full extent of safe homeowner action. Do not attempt to open the boiler casing, clean or spin the fan, touch the flue, or replace any part.
When to call a Gas Safe registered engineer
If E111 returns after one reset, or it persists once any obvious flue obstruction and bad weather are ruled out, it is time for a professional. By law, only a Gas Safe Register engineer may work on the fan, burner, gas valve, flue, sealed combustion circuit or PCB. It is illegal and dangerous for an unregistered person to attempt this work.
What the engineer will check
A competent engineer will typically test the fan and measure its actual speed, inspect the wiring and connectors between the fan and the PCB, check the flue for blockages or restriction, and read the boiler's fault history on the control board.
Depending on what they find, they may replace the fan, repair the wiring, or replace the PCB. A persistent E111 keeps the boiler in lockout until the underlying issue is fixed.
If you ever smell gas or suspect a leak, leave the property and call the National Gas Emergency line on 0800 111 999.
Typical Baxi E111 repair cost
Costs depend entirely on the underlying cause. These are indicative 2026 UK ranges for guidance only — always get a written quote first.
| Job | Indicative 2026 cost |
|---|---|
| Diagnostic call-out (independent Gas Safe engineer) | £60–£120 |
| Wiring / connector repair | £80–£150 |
| Fan replacement (parts and labour) | £250–£450 |
| Flue inspection and clearing | £80–£200 |
| Replacement PCB (control board) | £300–£500 |
For a wider picture, see our guide to boiler repair costs.
Related Baxi codes
If your boiler shows a different code, these sibling guides may help:
- Baxi E110 — the overheat lockout (a different fault to E111).
- Baxi E119 — low water pressure error.
- Baxi E133 — gas supply or ignition failure.
You can also browse the full Baxi fault codes hub.
Will boiler cover pay for an E111 repair?
This is general information, not financial or insurance advice — always check your own policy wording.
Many boiler cover and home-emergency plans will pay to diagnose and repair an E111 fan fault, including parts such as the fan or PCB, provided your boiler met the age and service conditions when you took the policy out.
What is often not covered is a boiler that was already faulty when cover started, and some policies exclude older appliances or apply parts limits.
Read what boiler cover includes to understand the typical limits, and our honest take on whether boiler cover is worth it for an older boiler prone to recurring faults.
Is a Baxi E111 fault dangerous?
The lockout itself is a safety feature — the boiler shuts down precisely to avoid burning gas without the correct airflow. But a repeating E111 signals a genuine fan or combustion-related fault that should be diagnosed by a Gas Safe registered engineer rather than repeatedly cleared. If you ever smell gas, leave the property and call 0800 111 999.
Can I fix E111 myself?
No. Beyond a single reset, a look at the external flue outlet from the ground, and confirming the gas supply is on, there is nothing a homeowner should do. Diagnosing and repairing the cause involves the fan, flue, wiring or PCB — all engineer-only work.
Will E111 clear on a reset?
It may clear if the cause was a one-off, such as a strong gust of wind disturbing the flue. But if the fan, wiring or control board is genuinely at fault it will return, often quickly. Reset once; if it comes back, book an engineer rather than resetting repeatedly.
How much does it cost to repair a Baxi E111?
Expect roughly £60–£120 for diagnosis, then around £250–£450 for a fan replacement, less for a wiring repair, or £300–£500 if the control board needs replacing. Always get a written quote before work begins.
What is the difference between E111 and E110 on a Baxi?
They are different faults. E111 is a fan-speed fault — the fan is not running at the correct speed for safe combustion. E110 is an overheat trip, where the heating water has reached its maximum temperature. The diagnostic steps and likely repairs are not the same.
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Compare boiler coverThis article is general information, not gas-safety or financial advice. Always have gas appliances checked and repaired by a Gas Safe registered engineer. In a gas emergency, call the National Gas Emergency line on 0800 111 999. Costs are indicative UK guides for 2026.