How to Fix an E133 Baxi Boiler Fault: Error Repair Guide

Last updated on October 12th, 2024

The E133 Baxi fault code is shown on the boiler display when there is a problem and your boiler goes to lockout.

I have been carrying out boiler repairs full-time for over a decade and having fault codes on the screen when I arrive is very welcome. Here I’ll show you how to deal with an E133 fault based on my on-the-job experiences.

What Does E133 Mean on a Baxi Boiler?

This error code is also used on Main and Potterton boilers (Baxi-owned). The Baxi, Main and Potterton E133 faults are the same.

The E133 fault code meaning according to a Baxi manual:

E133 indicates that the gas supply has been interrupted, ignition has failed or the flame has not been detected.

Baxi

Here are some of the most common causes from my experiences:

• Gas Supply Fault: The boiler has been locked out due to not getting any gas. This can be checked quite easily without having to open up the boiler
• Frozen Condensate Pipe: Another cause for could be a blocked or frozen condensate pipe. If it’s below zero cold weather and you have an external condensate pipe, there is a good chance it has frozen causing your boiler to lockout
• Faulty Boiler Parts: It could also mean that a part in the boiler is faulty and needs to be replaced, but a lot of the time in my experience it is a gas supply issue

How to Fix E133 Fault

The first thing I would check is that the gas is turned on at the gas meter emergency control valve (ECV).

Gas supply fault

If you have other gas appliances, like a gas hob or gas fire, check to see if these are working to find out if you are getting gas in the property.

Prepay gas meter: If you have a prepayment gas meter, make sure you are in credit, as this is quite a common situation I come across.

Frozen condensate pipe

If it’s freezing outside, having a frozen condensate pipe is possible. You can pour hot water on it to melt the frozen condensate water inside the pipe and reset the boiler.

Faulty boiler parts

A gas supply problem or a frozen condensate pipe are the most common causes of a Baxi E133 error but it could be caused by faulty boiler parts.

Here are some other potential causes:

• Faulty gas valve: Might need a new one
• Worn-out spark electrode: Might need to be cleaned, bent or replaced
• Faulty PCB (printed circuit board): The PCB is the brain of the boiler and might need to be replaced

How to Reset a Baxi Boiler

The first thing I would do on a Baxi boiler that is not working, no matter what fault code is showing, is to check the pressure and reset the boiler. This is the simplest way to get your boiler working again, as it might have just locked out.

Modern Baxi boiler

To reset a modern Baxi boiler (eg 600 or 800), you must find the reset button. This is a button that has ‘Reset’ on it. You have to press the button to reset the boiler.

Sometimes you have to hold it down for a few seconds, but on some Baxis, it just needs to be pressed and released.

Older Baxi boiler

If it’s an older Baxi (Duo-tec, 105 etc..) with a knob to turn the boiler on and off, then you will need to turn it fully anti-clockwise and hold it there (at R) until it resets.

Baxi E133 won’t reset

If your E133 error won’t reset, this means you have a problem that needs to be fixed before trying to reset it again. When the ignition has gone to lockout it won’t reset until the cause of the E133 error is fixed.

If you have fixed a gas supply issue and it still won’t reset, this could mean there is air in the gas pipe. You should try resetting it a few times to get the gas into the boiler and to get rid of the E133 error code.

Baxi boiler guides

• Baxi boiler no hot water
• Baxi boiler pressure
• Replace pressure relief valve
• Baxi boiler leaking

Conclusion

Fixing an E133 Baxi problem is usually done by fixing a gas supply issue. If you have a prepayment gas meter, make sure you put some money on and reset the boiler.

On a cold winter night, an E133 Baxi error is likely to be caused by a frozen condensate pipe. This is easily fixed by pouring hot water over the condensate pipe outside and resetting the boiler.

If you are sure you have gas and the condensate pipe isn’t frozen or blocked, you should ring a local gas engineer as it could be a gas valve problem.

Feel free to ask any questions in the comments below, and I’ll do my best to help. If you found this post helpful, please consider sharing it.

FAQs

How do you clear the fault code on a Baxi boiler?

To clear the fault code on a Baxi boiler, like Baxi E119 boiler fault and E133, you must reset the boiler. If the fault code appears after resetting the boiler, you will need to find and repair the problem causing your boiler to lock out and show a fault code.

Why is my Baxi boiler not turning on?

If your boiler is not turning on at all, and nothing is on the display, then you probably have an electric supply issue. You need to check the fused spur switch that should be next to the boiler. Make sure it is switched on and the 3 amp fuse is good. It could also be that the circuit breaker at the main fuse board (consumer unit) has tripped, so check there also.