Most homeowners don’t realise that a persistent E133 fault isn’t just “bad luck”, it’s caused by natural debris build-up over time. It is completely preventable.
If you’ve ever had your boiler lock out with an E133 ignition fault, you’ll know how frustrating it is, especially when it happens in the middle of winter. Across Bolton and surrounding areas, this is one of the most common ignition faults we see on Baxi 600 and 800 combi boilers.
Trying to resolve the issue yourself first? Follow our step-by-step guide on how to fix a Baxi E133 fault code .
The E133 fault code means your boiler has failed to ignite or detect a flame safely. While it can sometimes be caused by gas supply issues, repeated E133 faults are usually linked directly to internal component performance.
Your Baxi boiler relies on a highly coordinate, precise ignition sequence. If any single part of this sequence fails, the system locks out instantly:
Gas is released into the combustion burner chamber.
The ignition electrode creates a spark to ignite the gas fuel.
The flame is actively detected by the sensing electrode probe.
The boiler confirms safe operation and begins pumping hot water.
Over time, your boiler naturally builds up deposits inside the combustion chamber due to natural gas burning processes. These are:
This build-up collects directly on key components, especially the ignition electrode and flame sensor. When these parts become contaminated:
The most effective way to prevent ignition faults is simple: regular yearly boiler servicing. During a professional service, we:
Removing carbon build-up ensures a strong spark.
Ensures flame current registers correctly with the brain.
Guarantees safe combustion and gas air ratio checks.
Ensures delivery pressures meet manufacturers’ guides.
From experience working on boilers across Bolton, the majority of repeat E133 faults happen on boilers that haven’t been serviced regularly.
Once the issue goes beyond basic checks, it involves gas-related components and internal electrical systems. These are not safe to work on without the correct qualifications. Internal gas components must only be handled by a Gas Safe registered engineer.
Gas Safe Compliance Required
While basic external checks (like resetting or checking your meter) are safe, internal cleaning and inspection must be carried out by a Gas Safe registered engineer.
Tried the reset and it’s still failing? It could be a faulty gas valve or ignition electrode. We’ll have it firing again the same day where possible.
We carry out boiler servicing for £80 across Bolton and surrounding areas, working on Baxi boilers every week.
Our service is designed to:
Transparent pricing. No hidden surprises..
What’s included
If your Baxi is constantly showing E133, the internal components might be failing. An upgrade could save you £400+ a year on bills.
Boiler is over 10–15 years old.
Energy bills keep increasing.
Constant breakdowns or callouts.
Banging or whistling sounds
Cold spots around the house.
Yellow flame or pilot light issues.
Leaks or visible corrosion.
Lacks modern smart features.
Wider Coverage
Because we’re locally based in Bolton, we offer fast installation dates and reliable aftercare support, not a national call centre.
A clean boiler is a reliable boiler. If you want to avoid an E133 lockout next winter, book your Annual Boiler Service in Bolton for just £80.
