Baxi Potterton or Main E133 Fault code

Baxi Potterton or Main E133 Fault code

The Baxi E133 Fault: A Comprehensive Guide

Introduction: Hello there, dear Heatlab readers! Today, we're diving into a rather common, yet perplexing issue for many homeowners and professionals alike – (Psst, it's an ignition fault!) the notorious Baxi E133 fault. Found not just in Baxi boilers but also in Potterton and Main models, this error code can be a source of significant inconvenience.

Baxi E133 Fault

Understanding the E133 Error: The E133 error code is essentially an ignition lockout fault, indicating issues related to the boiler's gas supply or ignition system. This means that your boiler is having trouble igniting the gas, leading to disruptions in your central heating and hot water supply​​​​​​.

Common Causes: This error code can be caused by a variety of factors, including:

  1. Blocked or faulty gas valve.
  2. Damaged or defective ignition leads.
  3. Malfunctioning ignition electrode.
  4. Poor gas supply or pressure.
  5. Incorrect gas valve adjustment​​.

Troubleshooting Steps: Before you call in a professional, here are some steps you can take to potentially resolve the issue:

  1. Check the Gas Supply: Ensure the gas meter and shut-off valve are on. Verify if other gas appliances are functioning, which can help isolate the issue to your boiler​​.

  2. Examine the Ignition System: Look for visible damage to the ignition electrode and leads. Replacement may be necessary if damage is evident​​.

  3. Assess the Gas Valve: Check for signs of damage or blockage. Professional repair or replacement might be required if issues are apparent​​.

  4. Reset the Boiler: Sometimes, simply resetting the boiler can clear the E133 fault code. Turn off the boiler, wait a few minutes, then turn it back on​​.

  5. Clean the Ignition Electrode: If the electrode is dirty or corroded, cleaning it could resolve the issue. This involves turning off the boiler, removing, cleaning, and reinstalling the electrode​​.

Professional Assistance and Costs: While some fixes can be DIY, issues involving the gas valve or other internal components require a qualified gas engineer. The cost of fixing the E133 fault code varies depending on the specific issue and whether professional assistance is needed. Simple fixes like resetting the boiler or cleaning the ignition electrode can be done at little to no cost, while more complex repairs may lead to higher costs​​.

Safety Considerations: It's crucial not to ignore the E133 fault code. Continuing to use your boiler with this error could be risky, as it indicates a problem with the gas supply or ignition system. To avoid potential hazards, address the issue as soon as possible​​.

Prevention Tips: Regular boiler maintenance, including annual servicing by a qualified engineer, can help prevent issues like the E133 fault code. Keep an eye out for signs of wear or damage in your boiler’s components and address any problems promptly​​.

Conclusion: In conclusion, the Baxi E133 fault is a common issue that can often be resolved with some basic troubleshooting. While some of the fixes can be done by homeowners, others require the expertise of a professional. It's essential to approach this error with caution, given its connection to the boiler's gas supply and ignition system. Regular maintenance and prompt attention to any signs of malfunction can help prevent this fault from occurring. Remember, safety first!


  1. What does the Baxi E133 fault code indicate?

    • The E133 code signals an ignition lockout fault, typically related to problems with the gas supply or the boiler's ignition system.
  2. Can I fix the E133 fault on my own?

    • Yes, some basic troubleshooting like checking the gas supply, resetting the boiler, or cleaning the ignition electrode can be done by homeowners. However, if the issue involves more complex components like the gas valve, professional help is advisable.
  3. Is it safe to continue using my boiler with an E133 error?

    • No, it's risky to use the boiler with this fault code as it indicates an issue with the gas supply or ignition system. It's best to resolve the problem promptly.
  4. How can I prevent the E133 fault from occurring?

    • Regular maintenance and annual servicing by a qualified engineer are key to preventing this fault. Also, be vigilant for any signs of wear or damage in the boiler components.
  5. What are the costs involved in fixing an E133 fault?

    • The costs can vary. Simple fixes like resetting the boiler or cleaning the ignition electrode are usually low-cost. More complex repairs requiring professional assistance will be more expensive.

Table: Troubleshooting the Baxi E133 Fault

Step Action DIY or Professional Notes
1. Check Gas Supply DIY Ensure gas meter is on and other appliances are working.
2. Examine Ignition System DIY Look for damage to ignition electrode and leads.
3. Assess Gas Valve Professional Check for damage or blockage.
4. Reset the Boiler DIY Turn off, wait, and turn back on.
5. Clean Ignition Electrode DIY Remove, clean, and reinstall the electrode.
6. Call a Professional Professional If DIY steps don’t resolve the issue.


By following this guide, you should be well-equipped to understand and tackle the Baxi E133 fault. Remember, when in doubt, it's always safer to consult a professional. Stay informed and ensure your boiler's health for uninterrupted warmth and comfort.

All the best! Lee Gas safe registered engineer 

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