Home / Guides / Baxi E133 fault code
Baxi E133 fault code: what it means and what to do
E133 on a Baxi means the boiler couldn’t light. Baxi says it points to the gas supply, the ignition or a blocked condensate pipe. Here’s how to check each one and reset it.
- E1 / 33how E133 shows on many Baxi displays
- 5seconds to hold reset on many models
- E119low pressure, a different fault
A Baxi we’ve worked on
E133 is the code Baxi owners ring us about most. On many Baxi displays it doesn’t even show as E133: the screen flicks between E1 and 33.
Baxi says it means a problem with the gas supply, the ignition or flame, or a blocked condensate pipe. The boiler tried to light, didn’t manage it, and locked itself out.
Two of those three you can check yourself.
What to check
Gas first, then the condensate pipe.
Is gas getting to the boiler?
Try the hob. If nothing on gas works, check your meter: top up a prepayment meter if it’s run out, and make sure the gas hasn’t been turned off. If the supply’s the problem, it’s one for your gas supplier.
Is the condensate pipe frozen?
Baxi says a frozen condensate pipe shows as E133 or E28. Its advice:
- Switch the boiler off, and the electricity off at the wall
- Pour hot, but not boiling, water onto the frozen part, only if you can reach it from the ground
- Mind your footing on icy ground
- Power back on and restart the boiler
Baxi says you shouldn’t need an engineer for a frozen pipe. If it still won’t go after thawing, call a Gas Safe engineer.
Showing the reset
How to reset a Baxi
| If your boiler has | Do this |
|---|---|
| A reset button | Press it until the red light goes out |
| A temperature knob | Turn it fully anticlockwise and hold until the red light goes out, then turn it back |
| A selector switch with R | Turn it to R and hold for at least 5 seconds, then release |
From Baxi’s reset guide, checked 2 November 2026. The Baxi 600 and 800 Combi 2 and System 2 use a different style of code and reset, so check your manual.
When to call an engineer
If resetting doesn’t stick.
Baxi says that if lockout happens often, a fault is indicated and you should contact your installer or engineer. Our advice is the same as for any make: one reset, one more after a fix, then book a repair.
What we’d look at
- The ignition and flame sensing parts
- The gas pressure at the boiler
- The flue and the fan
- The condensate trap and pipe
If your Baxi is getting on and keeps locking out, it may be time to talk about whether it’s worth repairing. We’ll tell you straight.
Fault finding
What should I do next?
- Gurgling, freezing outsideThaw the pipe
Then reset.
- Showing E119Top up the pressure
Low pressure on most older Baxis.
- E133 keeps coming backBook a repair visit
£120 including VAT, before any parts.
- Old Baxi, always breaking downRepair or replace?
Our honest guide.
Common questions
What does E133 mean on a Baxi boiler?
The boiler couldn’t light. Baxi says it points to the gas supply, the ignition or flame, or a blocked condensate pipe.
Why does my Baxi show E1 and 33?
That’s E133. Many Baxi displays can only show two characters at a time, so they flick between E1 and 33.
Can a frozen condensate pipe cause E133?
Yes. Baxi says a frozen condensate pipe will show as E133 or E28. Thaw it with hot but not boiling water, then restart.
How do I reset a Baxi boiler?
It depends on the controls: press the reset button until the red light goes out, turn the knob fully anticlockwise and hold, or turn the selector to R and hold for at least 5 seconds.
What’s the difference between E133 and E119?
On most older Baxi models, E119 means the system pressure has dropped below 0.5 bar. Top it up and the boiler should run. E133 is an ignition fault.
Do newer Baxi boilers show E133?
The Baxi 600 and 800 Combi 2 and System 2 use a different style of code, so you may see something like E.04.10 instead. Check the manual for your model.
Related pages
Sources: Baxi, how to reset a Baxi boiler; Baxi, what do error codes E133 and E28 mean?; Baxi, thawing a frozen condensate pipe. Checked 2 November 2026.
Not sure what you need? Give us a shout.
Book online in a couple of minutes or give the office a call, Mon to Fri, 9am to 5pm. We’ll tell you what we think, and if the answer is to leave things as they are, we’ll say that too.
Worcester Bosch Accredited Installer
Guarantees of up to 12 years on the boilers we fit. Gas Safe registered. Fife Trusted Trader. 400+ customer reviews.