Baxi E133 Fault Code
Gas supply fault — the boiler failed to light or lost the flame during ignition and has locked out.
General guidance only — not a substitute for professional advice. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
What does the Baxi E133 fault code mean?
Gas supply fault — the boiler failed to light or lost the flame during ignition and has locked out.
Common causes
- No or low gas supply Common
The most common cause — gas turned off at the meter, a prepay meter out of credit, an isolation valve closed, or low gas pressure.
- Frozen condensate pipe Common
In freezing weather a blocked condensate pipe can stop the boiler firing and produce an E133 lockout.
- Ignition or flame-detection fault Sometimes
Faulty ignition leads, electrodes or a flame-sensing probe can prevent the boiler detecting the flame.
- Faulty gas valve or PCB Rare
A failing gas valve or printed circuit board can cause repeated ignition failure.
How to fix it
- Check your gas supply. DIY safe
Make sure other gas appliances work, the meter has credit, and the gas isolation valve under the boiler is open.
- Check the condensate pipe for ice. DIY safe
If the external pipe is frozen, thaw it with warm (not boiling) water.
- Reset the boiler. DIY safe
Hold the reset button to clear the lockout. Avoid repeated resets — 2 or 3 attempts is enough.
- Call a Gas Safe registered engineer. Gas Safe engineer
If E133 persists, the ignition components, gas valve or PCB need inspection by a Gas Safe engineer.
Parts you may need
- Ignition electrode · from £25
- Gas valve · from £150
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £80–£450, depending on the underlying cause.
Frequently asked questions
What does E133 mean on a Baxi boiler?
E133 is a gas supply / ignition fault — the boiler couldn't establish or detect a flame and locked out for safety.
Is E133 something I can fix myself?
You can safely check the gas supply and a frozen condensate pipe, then reset. If it keeps returning it's a gas component fault for a Gas Safe engineer.