Boiler
E110
The E110 error code on a Baxi boiler indicates a lockout caused by the boiler failing to detect a flame — meaning your boiler has tried to ignite and failed, leaving you without heating or hot water. It can range from a simple fix like a reset to a more serious fault requiring a Gas Safe registered engineer. In this article, we’ll walk you through exactly what E110 means, the most likely causes on Baxi boilers, the safe steps you can take yourself, and when it’s time to pick up the phone.
What does this error mean?
The E110 fault code on Baxi boilers (including popular ranges like the Baxi 200, 400, 600, Duo-tec, and Platinum series) signals an ignition lockout. In plain English, this means your boiler attempted to light its burner, but the flame either failed to ignite at all or lit briefly and then went out — and the boiler’s safety system detected this and shut everything down as a precaution. The boiler’s PCB (printed circuit board) monitors the flame via a component called the flame sensor or ionisation probe. If the sensor doesn’t detect a stable flame within a set number of attempts, the boiler locks out and displays E110 to protect you and your home. This is a safety feature, not a flaw — but it does mean the boiler will not attempt to restart on its own until the underlying issue is resolved or a manual reset is performed.
Est. repair cost
£80–£150 for a Gas Safe engineer call-out and minor repair (e.g. flame sensor or electrode replacement); £200–£400 if the gas valve or PCB needs replacing
🔍 Likely causes
🛠️ Step-by-step fix
Step 1 — Check your gas supply first: Before anything else, check that other gas appliances in your home (such as your gas hob or gas fire) are working normally. If they’re not, you likely have a gas supply issue. Call your gas supplier or National Gas Emergency Service on 0800 111 999 if you suspect a supply fault or smell gas.
Step 2 — Check the gas isolation valve near the boiler: Locate the gas isolation valve on the pipe leading into your boiler (usually a quarter-turn lever valve). If the slot in the valve is perpendicular to the pipe, it is closed — turn it so the slot is parallel to the pipe to open it. Only do this if you are confident it was accidentally closed and there is no smell of gas.
Step 3 — Perform a boiler reset: On most Baxi models, press and hold the reset button (often marked with a flame symbol or labelled ‘Reset’) for 3–5 seconds until the display changes. The boiler will attempt to restart. Consult your Baxi boiler manual for the exact reset procedure for your specific model, as it varies slightly across ranges.
Step 4 — Wait and observe: After resetting, watch the boiler for 60–90 seconds. Listen for the click of the igniter and the sound of the burner lighting. If it lights successfully and the E110 clears, monitor it over the next few hours to see if the fault returns. A one-off lockout after a power cut or gas interruption is not unusual.
Step 5 — Reset a second time if needed: If the first reset fails, wait 10 minutes and try once more. Baxi recommend no more than two or three reset attempts. If the boiler continues to lock out with E110 after two resets, do not keep resetting repeatedly — this will not fix an underlying fault and could mask a more serious problem.
Step 6 — Check your boiler pressure gauge: While not a direct cause of E110, very low boiler pressure (below 0.5 bar on the gauge) can contribute to ignition and operational faults. If the needle is in the red or below 1 bar, you may need to repressurise the system using the filling loop — refer to your Baxi manual for instructions specific to your model.
Step 7 — Do not attempt any further DIY: Beyond the steps above, all further investigation and repair on a gas boiler must be carried out by a Gas Safe registered engineer. Do not attempt to clean the ignition electrode, replace the flame sensor, adjust the gas valve, or access any internal components yourself. Working on gas appliances without Gas Safe registration is illegal in the UK and extremely dangerous.
📞 When to call a professional
You should call a Gas Safe registered engineer if: the E110 error returns after two reset attempts; the boiler has never fired at all since the code appeared; you can smell gas at any point (in which case call the National Gas Emergency Service on 0800 111 999 immediately and do not attempt to reset the boiler); or if the fault is recurring — coming back every few days or weeks. When you call, tell the engineer: (1) the exact error code displayed — E110; (2) which Baxi model and series you have (check the label on the front of the boiler); (3) what you’ve already tried (resetting, checking gas supply); and (4) whether the error is intermittent or permanent. This will help the engineer diagnose the fault faster and potentially save you call-out time and money. Always verify your engineer is Gas Safe registered — you can check at GasSafe Register.co.uk.
⚖️ Repair or replace?
For most Baxi E110 faults, repair is the right first step — provided your boiler is under 10 years old and has been reasonably well maintained. The most common fixes (ignition electrode replacement, flame sensor cleaning or replacement, gas valve repair) are relatively affordable and Baxi parts are widely available through UK trade suppliers. However, if your boiler is over 12–15 years old and is showing E110 alongside other recurring faults, or if the PCB has failed, the economics start to shift. A new PCB alone can cost £200–£400 fitted, and on an older boiler this may not represent good value. As a rule of thumb: if the repair quote exceeds 50% of the cost of a new boiler, or your boiler is over 12 years old with multiple faults, it’s worth getting a replacement quote. A new Baxi 200 or 400 combi boiler typically costs £1,500–£2,500 fully installed in the UK, depending on complexity. Baxi boilers come with manufacturer warranties of up to 10 years (depending on the range and whether annual servicing has been maintained), so always check whether your boiler is still under warranty before paying for any repair.