Baxi E133 Fault Code: What It Means and What to Do

If your Baxi boiler has ground to a halt and the display is flashing E133, you're probably standing in a cold house wondering how urgent this actually is. The short answer: E133 means your boiler has lost gas supply or failed to ignite, and it's shut itself down as a safety measure. It's one of the most common Baxi fault codes, and in many cases it's fixable in minutes, but not always something to poke around with yourself.

What does E133 actually mean?

On most Baxi combi and system boilers (including the Duo-tec, Ecoblue and Platinum ranges), E133 is logged when the boiler tries to ignite the burner but doesn't detect a flame, or when gas flow to the burner has been interrupted. The boiler's control board waits a set number of attempts, then locks out and shows the code rather than continuing to try and fail.

It's not the same as a pressure fault (that's usually E119 or E110 on Baxi units, and worth checking against our pressure guide if you're unsure which code you're actually seeing). E133 is specifically about gas and ignition, not water pressure.

Common causes of E133

• Gas supply interruption: a meter that's tripped, a gas card that's run out on prepayment meters, or a closed gas valve
• Weather compensation or delayed ignition: some Baxi models briefly hold off ignition in certain conditions, which can trip a false E133 on older firmware
• Faulty ignition electrode or PCB: over time these components wear and can fail to spark reliably
• Blocked flue or condensate issue feeding into an ignition lockout
• Low gas pressure from the supplier's network, though this is less common

What you can safely check yourself

Before booking an engineer, a few checks take two minutes and cost nothing:

1. Check other gas appliances (hob, fire) are working. If nothing gas-powered is on, you may have a supply issue rather than a boiler fault.
2. Check your gas meter hasn't tripped or run out of credit if it's a prepayment meter.
3. Try resetting the boiler once, following the reset button instructions in your manual. If E133 reappears immediately, stop resetting it repeatedly, repeated ignition attempts on a genuine fault isn't good for the boiler.
4. Check the boiler display for any other codes appearing alongside E133, which can help narrow down the cause.

If none of that clears it, this is a job for a Gas Safe registered engineer, not a DIY fix. Anything involving the gas valve, ignition electrode or PCB legally has to be handled by someone registered, and you can always verify an engineer's registration on the Gas Safe Register before they arrive.

When it's more than a one-off fault

If E133 keeps coming back after a reset, or your boiler is older and has needed repeat call-outs, it's worth asking whether repair is really the best use of your money. The Energy Saving Trust notes that older, less efficient boilers cost more to run as well as to maintain. Our guide to signs you need a new boiler covers how to weigh up repair against replacement, and our new boiler cost guide gives realistic figures for the Midlands.

Regular annual servicing catches worn ignition components before they cause a full lockout, which is usually cheaper than an emergency call-out.

Getting help fast

If you're without heating or hot water right now, don't wait around. Book an emergency callout and a Gas Safe engineer covering your area will get things moving again. If it turns out replacement makes more sense than repair, we can get you a fixed price with no obligation.