Baxi Boiler Error Codes: What E133, E119, E118 and the Rest Mean

Your Baxi has flashed an E-code and stopped. Here's what the common ones mean, what you can safely try, and where to stop and call a Gas Safe engineer.

It's the first hard frost of the year. You wake up to a cold house, walk to the boiler and find E133 glowing on the display. Nothing is firing. Your first thought is probably "that's going to cost me".

Take a breath. A Baxi error code is the boiler's way of saying it has found something and stopped on purpose. Some are small and fixable in minutes. Others should only be handled by an engineer. The trick is knowing which is which, and that's what this guide is for.

Baxi boilers show faults as an E followed by a number. Baxi's own advice is that several common codes, including E133 and E119, can simply be a frozen condensate pipe in cold weather. We'll cover that, the codes people ask about most, and how to reset.

Key takeaways

• In cold weather, a frozen condensate pipe is the first thing to check, and Baxi lists several common codes under it.
• E118 (low pressure) and E133 (gas or ignition) are the two most homeowner-friendly codes.
• Fan, flue, sensor, overheating and gas valve codes are for a Gas Safe engineer only.
• Code meanings vary by Baxi model. Your manual wins.
• Gas smell or carbon monoxide symptoms: leave and call 0800 111 999.

First: is this an emergency?

Smell gas? Act now, read later.

• Open doors and windows and leave the property.
• Don't switch lights or appliances on or off. No flames.
• If you can reach it safely, turn the gas off at the meter.
• Call the National Gas Emergency Service on 0800 111 999 (free, 24 hours) from outside.

No gas smell? Here is how we sort the codes below:

Do this first, whatever the code

1. Photograph the display. Note the exact E-code and your model name. An engineer will thank you.
2. Check the pressure gauge. When the system is cold, it should sit at roughly 1 to 1.5 bar.
3. Check the basics. Power on? Thermostat and timer calling for heat, with working batteries? Gas hob working? Credit on a prepayment meter?
4. Is it freezing outside? If so, look at the condensate pipe (next section).
5. Reset once. If the code returns, stop and call an engineer.

Have boiler or home emergency cover? Call your provider before you book an engineer yourself. With Smart Cover, repairs arranged without our approval may not be covered.

The frozen condensate pipe: Baxi's most common cold-weather culprit

Condensing boilers drain slightly acidic water through a plastic pipe, usually to the outside. In a hard frost that water can freeze and block the pipe, and the boiler locks out. Gurgling sounds beforehand are a classic clue. Baxi lists several codes, including E28, E53, E113, E119, E128 and E133, as ones where a frozen condensate pipe may be the cause.

How to thaw it safely

1. Switch the boiler off at the control panel and turn the power off at the wall.
2. Find the frozen section. It's usually the most exposed part of the pipe, often on an outside wall.
3. Warm it with a hot water bottle, a microwaveable heat pack or warm water from a watering can. Never use boiling water: it can crack the pipe.
4. Switch the power back on and restart the boiler.

Try: only if you can reach the pipe from the ground, safely.

Stop if: you'd need a ladder on an icy day, or it keeps re-freezing. Ask an engineer to insulate or reroute the pipe.

Four Baxi codes people search for most

E133: gas or ignition

The boiler tried to light and couldn't, usually because the gas supply was interrupted or the ignition failed.

Try: check the hob, meter credit and gas valve, thaw the condensate pipe in frost, then reset once.

Stop if: it repeats. Ignition parts need an engineer.

E118: low pressure

The water pressure has dropped too low for the boiler to run. It's common after bleeding radiators. On some Baxi models, low pressure shows as E119 instead.

Try: top up with the filling loop to about 1 to 1.5 bar, following your manual.

Stop if: it keeps dropping. That suggests a leak.

E128: flame failure

The flame went out or wasn't detected. Causes overlap with E133: gas supply, frozen condensate, or ignition parts.

Try: the same basic checks and one reset.

Stop if: it returns, especially with odd smells or noises.

E160: fan fault

The fan helps move combustion gases out through the flue, which makes this a safety-critical part.

Try: nothing beyond noting the code.

Stop: call a Gas Safe engineer.

Baxi fault code table

Baxi uses a lot of codes and meanings vary by model, so we've grouped the common ones. Treat it as a starting point, then confirm in your manual.

Meanings are common interpretations for typical Baxi boilers and vary by model. Manufacturers and guides sometimes differ on the same code (E28 and E119 are examples). If in doubt, your manual or Baxi's own support is the final word.

How to reset a Baxi boiler

Find the reset button on the front panel. Press and hold it for one to three seconds until the boiler restarts, then wait and see whether the code clears. Some codes stay on screen until the boiler stops detecting the fault, so give it a minute.

The rule is once. A reset is a second chance, not a fix. If the code returns, repeating it won't help. See our wider guide to boiler error codes.

When to stop and call a Gas Safe engineer

Boilers are sealed gas appliances, and gas work in the UK must be done by someone on the Gas Safe Register. Call when:

• a code returns after one reset, or a different one replaces it
• it relates to the fan, flue, sensors, circulation, overheating or gas valve
• there is leaking water, banging or whistling, soot or black marks around the boiler
• the flame, if you can see it, looks mostly yellow or orange rather than steady blue
• fixing it would mean taking the casing off. Always.

Check the ID. Every registered engineer carries a Gas Safe ID card with a photo, and you can verify them on the Gas Safe Register website. If you have boiler cover, call your provider first so they can arrange the engineer.

Carbon monoxide: the quiet one

Carbon monoxide has no smell, colour or taste. Symptoms feel like flu without a temperature: headaches, dizziness, nausea, tiredness. If several people at home feel unwell and it eases when you're out, take it seriously. Fit an audible CO alarm near the boiler and in bedrooms, test it, and if it sounds, open windows, leave and call 0800 111 999.

Warranty, servicing and what to do next

If your Baxi is still under manufacturer warranty, check the paperwork before booking anyone. Warranties often depend on annual servicing being kept up. If you have Smart Cover boiler cover, your boiler must also have been serviced in the 12 months before a breakdown claim, so keep your service records safe.

An annual boiler service is how most small faults get caught before they become winter lockouts. Bleed radiators that are cold at the top (our radiator guide takes fifteen minutes) and keep an eye on the gauge once a month. If you're watching running costs, see how to reduce your heating and gas bill.

And if the codes keep changing on an older boiler, repair or replace is worth weighing up calmly.

Baxi lockout at the worst moment?

Smart Cover boiler cover and home emergency cover are there for the covered breakdowns the checklist can't fix. Report an emergency any time on our 24/7 Emergency Helpline, 03333 449 247, and we'll arrange an engineer from our UK network for covered faults. For claims and other enquiries, call 03333 449 559.

Before you rely on cover, know the key terms:

• Cover is for gas boilers only. Oil, LPG and electric boilers are not covered.
• Your boiler must have been serviced in the 12 months before a breakdown claim.
• There is a waiting period from the start of your policy: 14 days for homeowner policies and 28 days for landlord policies.
• Claims are paid up to the claim limit on your policy schedule.
• Exclusions include wear and tear, sludge and limescale, faults that existed before your policy started, and repairs arranged without contacting us first.

See boiler cover or home emergency cover. Read the policy documents and IPID for full terms. Cover helps with repair costs for covered breakdowns. A gas smell or CO symptoms are always an emergency call to 0800 111 999 first.

Official sources

•   Gas Safe Register: find and check registered engineers
•   HSE: gas safety in the home
• National Gas Emergency Service: 0800 111 999
• Your Baxi manual or Baxi's own website for model-specific fault code lists

General information only. This guide isn't a substitute for your boiler manufacturer's instructions or advice from a Gas Safe registered engineer. Fault code meanings vary by model. Smart Cover is not affiliated with Baxi. This is a marketing communication. Cover is subject to policy terms, limits and exclusions. Reviewed 11 November 2026.

Smart-Cover Insurance Services, Smart Cover and Smart Cover 247 are trading names of Smart-Cover Direct Limited (FRN 600428), an Appointed Representative of City and Commercial Limited (FRN 314346), which is authorised and regulated by the Financial Conduct Authority. The Financial Ombudsman Service can be contacted at www.financial-ombudsman.org.uk.