How to Clear Baxi Boiler E133 Ignition Fault
Last updated: 7 September 2026
Check the gas supply, check the condensate pipe, and reset the boiler.
Overview
Baxi boiler E133 ignition fault indicates a problem with the gas supply or ignition system. This guide covers diagnosing and fixing the E133 error.
Step-by-Step Fix
Before beginning any repair, ensure you have isolated power or water supplies. Clear your workspace, gather standard hand tools, and wear appropriate personal protective equipment (PPE).
- First, check that the gas supply to the boiler is turned on. Locate the gas isolation valve near the boiler and ensure it is fully open. Check that the gas meter is not displaying an error or that the gas supply has not been interrupted by the supplier.
- Check the condensate pipe for any blockages or ice that could be preventing the boiler from igniting. If the condensate pipe is frozen, thaw it by pouring warm water over the pipe. Do not use boiling water, as this can damage the pipe.
- Reset the boiler by pressing the reset button on the front panel. This is usually a small button that may be labelled with a circular arrow symbol. Hold the button for a few seconds until you hear the boiler attempt to restart.
- If the boiler attempts to ignite but fails, wait a few moments and try resetting it again. Sometimes the boiler may need a few attempts to purge any air from the gas line. If the boiler still does not ignite, there may be a problem with the gas supply or the ignition system.
- Check the ignition leads and electrodes for any signs of damage or wear. If the electrodes are dirty, clean them with a soft brush. If the leads are damaged, they will need to be replaced by a Gas Safe registered engineer.
- Check the burner for any signs of blockage or debris. If the burner is blocked, the gas will not ignite properly. This is a job for a Gas Safe registered engineer, as it involves working with the gas supply.
- If you have checked the gas supply, the condensate pipe, and the ignition system, and the boiler still shows E133, call a Gas Safe registered engineer. There may be a more serious fault with the gas valve or the ignition control board.
- After the repair, test the boiler by turning on the heating or hot water. Ensure the boiler fires up correctly and that the E133 error has cleared.
Common Error Codes
Review the common error codes and operating symptoms below to quickly identify the root cause of the fault before ordering replacement parts.
| Symptom / Code | Likely Root Cause | Recommended Resolution |
|---|---|---|
| E133 | Ignition fault | Check the gas supply, check the condensate pipe for blockages, and reset the boiler. If the error persists, call a Gas Safe registered engineer. |
| EA | Ignition fault (Worcester Bosch) | Check the gas supply and the condensate pipe. If the error persists, call a Gas Safe registered engineer. |
| E119 | Low system pressure | Repressurise the boiler using the filling loop. Check for leaks in the system that could be causing the pressure to drop. |
| E9 | Low system pressure (Worcester Bosch) | Repressurise the boiler using the filling loop. If the pressure drops again, there may be a leak in the system. |
Frequently Asked Questions
What does Baxi E133 error mean?
Baxi E133 error indicates that the boiler has tried to ignite but failed to do so. This is often due to a gas supply issue, a frozen condensate pipe, or a problem with the ignition system. It is a common error that can usually be resolved by checking the gas supply and condensate pipe.
How do I reset Baxi boiler E133 error?
Press the reset button on the front panel of the boiler. Hold it for a few seconds until you hear the boiler attempt to restart. If the boiler does not restart, check the gas supply and condensate pipe before trying again.
What causes Baxi E133 error?
Baxi E133 error is caused by the boiler failing to ignite. This can be due to a gas supply issue, a frozen condensate pipe, a faulty ignition electrode, or a problem with the gas valve. It can also be caused by low gas pressure from the supplier.
Can I fix Baxi E133 error myself?
You can check the gas supply and the condensate pipe. If the error persists after these checks, you will need to call a Gas Safe registered engineer. Do not attempt to work on the gas supply or the ignition system yourself, as this is dangerous and illegal.