Baxi boiler fault codes — what they mean and what to do
Seeing an 'E' code flash up on your Baxi? Here's what it's telling you, what's safe to check yourself, and when to call us out.
What a fault code is telling you
Your Baxi boiler keeps an eye on itself. When something isn't right, it stops and shows an error code on the display so you know roughly what's wrong.
Most Baxi codes start with an 'E' followed by a number. They look alarming but often aren't. Some point to simple things you can sort in a few minutes, like low pressure or a frozen condensate pipe.
Others mean a part has failed and needs a Gas Safe registered engineer. We'll always tell you which is which, and never ask you to touch anything to do with gas.
Codes vary a little between Baxi models, so check your manual for the exact wording. The most common ones are below.
Common Baxi fault codes
| Fault code | What it means | What to do |
|---|---|---|
| E133 | Ignition failure — no flame detected. Often a gas supply issue, an ignition fault, or in cold weather a frozen condensate pipe. | Check your other gas appliances work. Reset once. If it returns, book a Gas Safe registered engineer. Smell gas? Call 0800 111 999. |
| E119 | Water pressure switch error — the pressure switch hasn't operated. On most models this means system pressure has dropped too low (typically below about 0.5 bar), but on some Baxi models it can be a switch or wiring fault rather than genuinely low pressure. | Check the gauge first. Only top up via the filling loop (to about 1.0–1.5 bar) if it actually reads low. If the gauge reads normal but E119 stays, that's a switch fault for a Gas Safe registered engineer. If pressure keeps falling after a top-up, you've likely got a leak — book an engineer. |
| E118 | Primary system water pressure too low (below about 0.5 bar). | Top up via the filling loop to about 1.0–1.5 bar. Repeated drops point to a leak — book a Gas Safe registered engineer. |
| E110 | Boiler overheat — the primary water has got too hot and the safety cut-out has tripped. | Don't keep resetting an overheat fault. Check pressure and that radiator valves are open, then book a Gas Safe registered engineer. |
| E125 | Primary circuit circulation fault — water isn't circulating properly. Often a stuck pump, trapped air or a blockage. | Check pressure and that the system isn't airlocked. This usually needs an engineer to check the pump and circulation. |
| E128 | Flame loss during operation — the boiler lit but lost the flame repeatedly (after several attempts). In cold weather this can also be caused by a frozen external condensate pipe. | Reset once. If it returns, book a Gas Safe registered engineer. If you smell gas, call 0800 111 999. |
| E131 | Flue overheat lockout — the flue safety device has tripped. | This is a safety lockout. Don't keep resetting it — book a Gas Safe registered engineer to investigate. |
| E160 / E161 | Fan fault or fan wiring fault — the fan isn't running correctly. | This needs testing. Reset once, then book a Gas Safe registered engineer if it sticks. |
| E168 | PCB lockout / general fault — often linked to an electrical supply problem outside the boiler's tolerance. E168 often appears after another fault code once the boiler has been reset, so the original code may be the real issue. | Check the boiler has a steady power supply. If E168 returns, book a Gas Safe registered engineer to diagnose it. |
| E133 / E119 / E128 / E53 / E23 (frozen condensate) | In cold weather, several Baxi lockout codes can be caused by a frozen external condensate pipe. Baxi lists E23, E53, E133, E119 and E128 among the codes a frozen condensate pipe can trigger. | Check for a frozen external condensate pipe and thaw it gently with warm (not boiling) water if it's safe to reach, then reset. Otherwise book a Gas Safe registered engineer. |
Safe checks before you call anyone out
These are the only things worth trying yourself. If a code involves gas, skip straight to a Gas Safe registered engineer.
- Check the pressure gauge — it should sit around 1.0 to 1.5 bar when cold.
- Top up via the filling loop only if pressure's genuinely low (E118, or E119 when the gauge reads low), then close the valves fully.
- In cold weather, check the external condensate pipe for ice and thaw it gently with warm (not boiling) water if it's safe to reach.
- Make sure the boiler has power and the programmer is set to come on.
- Check your thermostat is calling for heat and the batteries aren't flat.
- Confirm your other gas appliances work, to rule out a wider supply issue.
- Reset the boiler once — just once. Don't keep resetting an overheat (E110) or flue lockout (E131) fault, and don't keep clearing a code that comes straight back.
- If you smell gas, stop everything. Call 0800 111 999, open windows, turn off the gas at the meter if it's safe to reach, don't touch electrical switches, and leave the house.
The codes Baxi owners ask about most
E133 — ignition failure
This is the one most Baxi owners see. The boiler tried to light and couldn't detect a flame, so it shut off to stay safe.
First, check your other gas appliances. If the hob won't light either, it could be your gas supply. In cold weather, check whether your external condensate pipe has frozen, as that can also cause E133. Reset the boiler once.
If E133 comes straight back, stop there. The ignition system or gas valve may need a Gas Safe registered engineer. If you smell gas at any point, call 0800 111 999.
E119 and E118 — pressure faults
These are usually among the friendlier faults to see. E118 means your system pressure has dropped too low for the boiler to fire. E119 is a pressure-switch error — on most models that also means low pressure, but on some Baxi models the switch itself can be at fault even when pressure reads normal.
Check the gauge first. If it reads low, find the filling loop — usually a silver braided hose under the boiler. Open both valves slowly until the gauge reads between 1.0 and 1.5 bar, then close them fully.
If the gauge already reads normal but E119 stays, don't keep topping up — that points to a switch fault for a Gas Safe registered engineer. And if pressure keeps falling after a top-up, you've probably got a small leak somewhere; book an engineer to trace it.
E110 — overheating
E110 means the primary water got too hot and the safety cut-out tripped. The boiler is doing exactly what it should.
Low pressure, trapped air, sludge or a tired pump can all cause it. Check your pressure gauge and make sure radiator valves are open.
Don't keep resetting an E110. Repeatedly resetting an overheating boiler can hide a real fault, and the lockout is a genuine safety trip. The heat exchanger, pump or circulation may need attention — that's an engineer job.
Where to find your Baxi display and reset
Baxi's popular combi and system ranges — including the Baxi 800, 600 and 400 series, the Platinum and Platinum+ models, and the older Duo-tec, EcoBlue and Megaflo lines — show error codes on the screen on the front of the boiler.
On most modern Baxi boilers the display is a small digital screen behind the front flap, with a reset button (often marked with a flame or 'reset' symbol) nearby. Press and hold it for a few seconds to attempt a single reset.
Only reset once. If the same code returns, don't keep pressing it — that won't fix the underlying fault and can mask a real problem. Never reset an overheat (E110) or flue lockout (E131) repeatedly. When a code won't clear, the next step is a Gas Safe registered engineer.
If your model uses slightly different wording or a longer code, check the user manual that came with the boiler — Baxi lists the exact meanings per model.
When a code won't clear — how Smart Plan helps
If you've checked the simple stuff and the code's still there, the next step is a Gas Safe registered engineer. That's where we come in.
Smart Plan is a service plan, not insurance. You've got two easy options when your Baxi plays up.
Need it fixed now?
Book a one-off repair and we'll send a Gas Safe registered engineer to diagnose the fault and work to get your heating back on.
Want cover for next time?
Take out an ongoing Smart Plan boiler module and you're set up for the next time a code appears. Parts and labour are included up to your cover limit.
Cover is modular, so you choose only the modules you want. Boiler cover runs up to £500 per year if your boiler's under 7 years old, or up to £200 if it's older. A £95 call-out fee applies.
We've looked after over 15,000 customers, we've been trading since 2014, and we're rated Excellent on Trustpilot. When a fault code won't budge, we'll send a Gas Safe registered engineer to put it right — parts and labour included up to your cover limit.
Baxi fault code FAQs
Is boiler cover the same as insurance?
No — it's a service plan, not insurance. You pick the cover modules you want, and when something breaks we send a Gas Safe registered engineer to fix it, with parts and labour included up to your cover limit.
What does E133 mean on a Baxi boiler?
E133 is an ignition failure — the boiler couldn't detect a flame, so it shut off to stay safe. It's often a gas supply issue, an ignition fault, or in cold weather a frozen condensate pipe. Check your other gas appliances and reset once. If E133 returns, book a Gas Safe registered engineer. If you smell gas, call 0800 111 999.
How many times should I reset my Baxi boiler?
Just once. If the same code comes straight back after a reset, stop. Don't repeatedly reset an overheat (E110) or flue lockout (E131) fault at all. Repeated resets can hide a real fault — book a Gas Safe registered engineer instead.
Can I fix a Baxi fault code myself?
Only the safe basics — topping up pressure for E118 (or E119 if the gauge reads low), thawing a frozen condensate pipe, checking the thermostat, or a single reset. Anything involving gas, the fan, the PCB or internal parts needs a Gas Safe registered engineer. Never attempt a gas repair yourself.
Why does my Baxi keep dropping pressure after I top it up?
If you keep seeing E118 or E119 after re-pressurising, it usually points to a small leak in the system. Keep an eye on the gauge and book a Gas Safe registered engineer to trace it.
What should I do if I smell gas?
Call the National Gas Emergency Service on 0800 111 999 straight away. Open your windows, turn off the gas at the meter if it's safe to reach, don't touch any electrical switches, and leave the property.
Does Smart Plan cover Baxi boilers?
Yes. Our boiler module covers most makes, including Baxi. Cover runs up to £500 per year if your boiler's under 7 years old, or up to £200 if it's older, with a £95 call-out fee.
Code still showing? We'll send a Gas Safe registered engineer.
Book a one-off repair or set up an ongoing Smart Plan boiler module. A service plan, not insurance — parts and labour included up to your cover limit.
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