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Last updated: 7th June, 2024


Baxi Boiler E133 Error Code

Baxi Boiler E133 Error Code

Key takeaways

  • The E133 error on a Baxi boiler signifies an ignition lockout or gas supply issue.
  • Homeowners can attempt to reset the boiler, but more serious faults require a professional.
  • Repairs must be carried out by Gas Safe registered engineers to ensure safety and compliance.

Understanding boiler error codes is essential in determining the proper course of action. The presence of an E133 code specifically highlights a safety feature in Baxi boilers that prevents operation if a fault is detected.

Encountering an E133 error code on a Baxi boiler can be a source of frustration for homeowners. This code indicates an ignition lockout or a problem with the boiler's gas supply, calling attention to potential issues that can disrupt normal operation. 

The E133 error requires diagnostic procedures to understand the underlying cause, which may range from simple fixes like resetting the boiler to more complex faults that necessitate professional intervention.

Understanding boiler error codes is essential in determining the proper course of action. The presence of an E133 code specifically highlights a safety feature in Baxi boilers that prevents operation if a fault is detected. 

Homeowners may perform basic troubleshooting, like checking for visible issues or trying a reset. However, complex repairs, especially those that deal with gas supply, should be conducted by a Gas Safe registered engineer to ensure safety and compliance with regulatory standards.

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What Is a Boiler Error Code?

A boiler error code is a specific diagnostic tool that signals to the user there is an issue within the heating system that requires attention. They serve as a valuable first step in the troubleshooting process.

Explain What Boiler Error Codes Are in General

Boiler error codes are alphanumeric sequences displayed on the control panel of a boiler. These codes are programmed to alert users to specific malfunctions or irregularities in the boiler's operation. Upon detection of a fault, the boiler's internal monitoring system generates a corresponding error code, which usually halts the operation to prevent damage or unsafe conditions.

  • Fault: The term signifies a malfunction within the boiler's components or system.

  • Error Code: This is the specific code related to a particular fault.

  • Boiler Maintenance: Regular check-ups to ensure the system operates efficiently.

Importance of Understanding Error Codes for Boiler Maintenance

Comprehending what different error codes represent is crucial for effective boiler maintenance. They provide immediate insights into the nature of a problem, which can:

  • Facilitate faster troubleshooting.

  • Help owners and technicians take appropriate measures to rectify the issue.

Grasping the meaning behind these codes can thus mitigate extensive damage, promote safety, and extend the lifespan of the boiler. Regular maintenance, coupled with an understanding of fault codes, ensures that a boiler remains in good working condition, maintains performance levels, and adheres to safety standards.

What Does the Baxi Boiler E133 Error Code Mean?

When a Baxi boiler displays the E133 error code, it signifies a critical issue relating to gas supply or ignition. This code requires immediate attention to ensure the boiler's safe and efficient operation.

Detailed Description of the Specific Error Code

E133 is a specific fault code that appears on Baxi boilers when the unit has a problem with gas supply or ignition process. It is a prevalent issue that stops the boiler from functioning correctly until rectified.

Possible Reasons Why This Error Code Appears

The E133 error indicates several potential causes:

  • Gas Supply Issues: A common reason for seeing E133 on the display is a disruption in gas supply to the boiler. This could be due to the mains supply being turned off or a fault within the supply line.

  • Ignition Failures: If the boiler attempts to ignite but fails, this can trigger the E133 error code. Potential culprits include damaged ignition electrodes or issues with the boiler's printed circuit board (PCB).

  • Faulty Gas Valve: The gas valve controls the flow of gas into the burner. A defective valve may not open properly, leading to ignition problems.

  • Condensate Pipe Problems: A frozen condensate pipe or blockage can lead to a build-up of condensation, triggering the E133 fault.

  • Pressure Irregularities: Incorrect gas pressure either too high or too low may cause the boiler to lock out and display the E133 error.

These issues are safety mechanisms designed to prevent damage to the boiler or risk to occupants, thus requiring immediate inspection and repair by a qualified engineer.

Signs of the Baxi Boiler E133 Error Code

Recognising the signs and symptoms of the E133 error code is essential for prompt and effective troubleshooting of a Baxi boiler. This specific fault code indicates an ignition issue or problems related to the gas supply.

List and Explain Common Signs and Symptoms That Indicate This Specific Error

  • Control Panel Notification: The most immediate sign that an E133 fault has occurred is the display of the error code itself on the boiler's control panel. The appearance of 'E133' indicates the boiler has recognised a problem and is alerting you to take action.

  • Ignition Failure: When the boiler attempts to ignite but fails, it's a clear symptom. This malfunction could be intermittent or consistent, resulting in the inability to heat water or warm the household.

  • Absence of Flame: If you observe that there is no flame when the boiler operates, this could be a direct sign of the E133 error. The absence of a flame signifies that ignition has not been successful, despite the boiler's attempts to initiate the process.

  • Fluctuating Water Temperature: Another symptom associated with the E133 fault is water temperature inconsistency. Difficulty maintaining a stable temperature could imply an underlying ignition fault.

  • Boiler Lockout: In some events, the boiler may enter a safety lockout mode following several unsuccessful ignition attempts. This safety feature prevents further attempts that could potentially be unsafe without resolving the error.

The presence of one or multiple symptoms should prompt further investigation and likely, intervention by a qualified engineer to ensure the continued function and safety of the Baxi boiler system.

Can I Fix This Boiler Error Code Myself?

Dealing with a Baxi Boiler E133 error code can be a bit technical, but certain steps can be safely performed at home to resolve the issue without the immediate need for professional intervention.

DIY Tips for Resolving the Error

Firstly, resetting the boiler can sometimes resolve the E133 error. The user can attempt this by locating and pressing the reset button on the boiler interface. If the error persists, the homeowner can also check the gas supply. They should ensure that the gas stopcock is fully open and that there is gas flowing into the house by testing other gas appliances. Additionally, a routine examination and cleaning of the ignition electrode might be in order, as a dirty electrode can prevent successful ignition.

  1. Press the reset button on your boiler.

  2. Confirm the gas supply is active; other gas appliances should be working.

  3. Clean the ignition electrode carefully to remove any buildup.

Warnings or Advice on When to Avoid DIY and Seek Professional Help

However, it's important to know when to step back. If you've conducted the basic checks and resets without any change, it's time to consider professional repair. Especially if the issue might involve intricate parts such as the printed circuit board (PCB), professional expertise is paramount. Moreover, tampering with gas appliances without the proper knowledge and certification is not only likely to void any warranty but also poses serious safety risks.

  • Avoid DIY if there's no change after a reset.

  • Don’t attempt repairs if you suspect a faulty PCB.

  • Prioritise safety and seek professional help if unsure.

Do I Need to Contact a Gas Safe Engineer to Fix This Error Code?

The Baxi boiler E133 error code signals an issue with the gas supply, necessitating expert analysis. Accurate diagnosis and repair by a Gas Safe engineer ensures safety and compliance with legal regulations.

Advice on When It's Necessary to Call a Professional-

In the event of an E133 error, first ensure your gas supply is active and the boiler reset attempt has been made. If the issue persists beyond these initial checks, professional assistance is required. A Gas Safe registered engineer should be contacted if:

  • The boiler fails to operate after a reset.

  • There is evidence of a continuous gas supply malfunction.

  • Annual servicing has not been carried out to identify this issue earlier.

Situations involving gas appliances carry inherent risks. Consequently, expertise from a qualified engineer is imperative to rectify the E133 code safely.

All of iHeat’s engineers are fully qualified and Gas Safe, ensuring a swift and safe installation.

Explanation of What a Gas Safe Engineer Is and Why Their Expertise Is Important

A Gas Safe registered engineer is a technician certified to work with gas appliances. Such accreditation is both a legal requirement and a guarantee that the engineer has the necessary skills to manage gas safety effectively. The importance of their role includes:

  • Ensuring the boiler repair complies with current safety standards.

  • Possessing the capability to detect and remedy faults beyond the scope of lay knowledge.

  • Implementing fixes that prevent future complications.

Considering that a compromised gas appliance can lead to hazardous situations, the appointment of a Gas Safe engineer represents an investment in both safety and peace of mind. Regular maintenance and timely professional repair can extend the life of a boiler, ensuring it operates efficiently and without risk to occupants.

How Much Does Fixing the Baxi Boiler E133 Error Code Cost?

Diagnosing and repairing the E133 error code in Baxi boilers involves several variables, which influence the overall cost. One may experience a range of expenses depending on the complexity of the fault and the repair interventions needed.

General Cost Range for Fixing This Error

The cost of repairing an E133 error code on a Baxi boiler typically fluctuates between £150 to £500. This range accounts for the most straightforward fixes, such as resetting the boiler or thawing a frozen condensate pipe, to more costly repairs involving part replacements.

  • Minor Fixes: £150 - £200

    • Resetting the boiler

    • Thawing the condensate pipe

  • Major Repairs: £300 - £500

    • Replacing the gas valve

    • Repairing or replacing the printed circuit board (PCB)

These figures include the fees charged by Gas Safe registered engineers for their service and time. It is important to note that costs can vary by region and the engineer's level of experience.

Factors That Might Affect the Cost

Several factors can influence the final bill for rectifying the E133 fault:

  • Extent of Damage: If the boiler has sustained significant damage or wear, this could necessitate more extensive repairs or even a full replacement of parts.

  • Cost of Parts: Some parts, such as the gas valve or electrodes, may be pricier due to their function or the boiler model.

  • Engineer’s Rates: Charges may vary based on the engineer's expertise and reputation.

  • Emergency Call-outs: If one requires immediate assistance outside of normal working hours, this will likely increase the cost.

  • Boiler Age and Condition: An older boiler may have out-of-production parts, making repairs more expensive.

  • Payment Method: Some engineers might offer different rates for payment methods such as credit or if the customer has a pre-paid meter.

Prices may also be impacted by whether the repair is a short-term fix or a long-term solution, with the latter potentially offering better value for money despite a higher upfront expense.

Do I Need a New Boiler?

When faced with an E133 error code on a Baxi boiler, it is crucial to understand whether a simple repair will suffice or if it's time for a new boiler. This section outlines the key considerations.

Criteria to Decide Whether a Repair Is Sufficient or If a New Boiler Is Required

Diagnosing the severity of an E133 error is essential. If the issue lies with a simple fault, such as a blocked gas valve or a defective ignition lead, a repair by a Gas Safe registered engineer might resolve the problem. It is when repairs become recurrent or the cost of fixing approaches that of a new boiler that one should contemplate replacement.

Information on the Lifespan of Boilers and When Replacement Is Typically Recommended

Boilers, much like any home appliance, have an expected lifespan—typically between 10 to 15 years for brands like Baxi and Potterton. Replacement is usually considered when the boiler reaches this age range, particularly if performance declines or breakdowns become frequent.

How Much is a New Boiler?

Boilers can be a daunting purchase for many people as they’re an appliance with a lot of responsibility, providing heat for you and your family is something you want to get right. Boilers aren’t exactly a quickly disposable item either, potentially lasting you a decade.

New boiler cost can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap


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System to combi conversion


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New boiler install


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Back boiler to a combi


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System to system


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The discussion on the Baxi boiler E133 error code demystifies its common causes and the steps required for troubleshooting and resolution.

Summarise the Key Points Discussed in the Blog Post

The E133 error code is typically associated with problems in the gas supply or ignition system. Identifying the root cause is essential for a homeowner and may involve checking for a frozen condensate pipe, blocked gas valve, or faulty ignition leads.

Critical steps for addressing the issue include:

  • Thawing a Frozen Condensate Pipe: If the condensate pipe is frozen, carefully pouring warm water over it can resolve the problem. Following this, resetting the boiler is advisable.

  • Inspecting the Gas Valve: The gas valve should be checked for blockages. If the valve is faulty, a Gas Safe registered engineer must be consulted.

  • Examining Ignition Leads: Damaged or defective ignition leads can prevent proper ignition. These should be inspected and replaced by a qualified individual if found to be the issue.

Preventative measures are also crucial to avoid future occurrences of the E133 fault code. Regular maintenance and servicing can help ensure that components such as the condensate pipe and gas valve remain in good working order, precluding the need for emergency repairs. It is imperative that any rectification is carried out by a competent engineer.

Frequently Asked Questions

How do I fix my Baxi boiler E133 error?

To rectify an E133 error on a Baxi boiler, first check the gas supply to make sure it is on and that there are no issues with supply pressure. Then, reset the boiler according to the user manual. Persistent problems may require professional service to inspect the ignition system or flame detection sensors.

What does 133 mean on a Baxi boiler?

The E133 code on a Baxi boiler indicates that the boiler has experienced an interruption in gas supply, a failure in the ignition process, or the flame has not been detected after several attempts. This is a safety feature to prevent gas from accumulating without being ignited.

How do I clear the error code on my Baxi boiler?

To clear the E133 error code, you can try resetting the boiler using the reset button or turning it off and on again using the main power switch. If the code persists, it may indicate a more serious issue that requires attention from a qualified technician.

How do you ignite a Baxi boiler?

To ignite a Baxi boiler, ensure the gas supply is on. Then, follow the startup procedure outlined in the boiler's user manual, which typically includes setting the thermostat to a desired temperature and using the boiler's control panel to initiate ignition.

Why is my Baxi boiler not igniting?

If a Baxi boiler fails to ignite, it could be due to a problem with the gas supply, such as valves not being open or low pressure. It might also be an issue with the ignition system itself, including faulty spark electrodes or problems with the flame sensor.

How do I get the flame back on my boiler?

Reigniting the flame in a boiler involves checking gas supply valves, ensuring good pressure, and following the boiler's ignition procedure. If these steps do not work, the flame sensor or other components may need cleaning or replacement.

How do you fix a flame failure on a Baxi boiler?

Fixing a flame failure on a Baxi boiler may require cleaning or repositioning the flame sensor to ensure it can properly detect the flame. If these actions don't resolve the issue, it's best to consult a professional engineer who can pinpoint and repair the cause of the flame failure.

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Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.