Baxi boilers are popular in the UK due to their low cost but are also well known for their reliability, however, there are a few common issues that can occur, causing a breakdown.

This guide will help to identify the most common five Baxi boiler issues and advise some troubleshooting tips to assist with getting the heating system back up and running again.

Some of the issues can be managed yourself, where you feel confident to do so, whereas some will require the assistance of a qualified Gas Safe engineer.

Common Baxi Boiler Problems

#1 Leaking boiler

Boilers can develop leaks which along with water damage, can cause immediate problems as the safety mechanisms can shut down the boiler.

Some Baxi boiler models appear to be prone to leaks such as the Solo range, 105HE, and 133HE Plus for some reason, however, leaks can occur in any model. When a leak occurs, often it is caused by a problem with wear and tears on the pump or diverter value housing over time. Other causes can be due to pressures issues or boiler vibrations causing the plastic elements within the boiler unit to crack over time.

In addition, depending on the amount of water damage that has occurred during a leak, the electrical parts inside the boiler could require replacing too.

Any leak will require a call out to a qualified Gas Safe engineer to investigate the matter further, diagnose the source, and provide a quote for any replacement parts. Always bear in mind that the costs of any replacement parts will also require the cost of fitting on top. Repairs can be expensive and sometimes it is more economical to replace the entire boiler than specific parts, especially with an aging boiler.

#2 Hot water or heating but not both

Another common fault is that either the hot water or heating works at any one time, but not both. This is often a sign that there is an issue with the diverter valve, an internal part that directs the heated water to the part of the heating system that it is needed.

As the diverter value is situated inside the boiler, a qualified Gas Safe engineer will be required to investigate if the valve is blocked or damaged, or if another concern is at fault.

The typical costs of a new diverter valve are around £300, therefore if a replacement is needed it is worthwhile considering the age of the boiler and if a new unit entirely would be more cost-effective.

Related boiler problems:

• How to descale a boiler.
• Boiler overheating.
• What is the age of your boiler? 
• How to balance your radiators.
• Faulty boiler heat exchanger.
• Boiler PCB faults.
• Boiler not igniting.
• No power to your boiler.

#3 Noise from the boiler

Most boilers will make low-level noises when functioning such as humming or water flowing sounds, however, if a banging noise has been noted the boiler may need some further attention.

There can be a range of issues that can cause noise and therefore a qualified Gas Safe engineer would need to be called upon to investigate further by undertaking an array of tests. However, with Baxi boilers, noise can often be attributed to a broken burner, which can also be confirmed by the fault code 128 being shown on the display panel.

If the engineer confirms that the burner is the cause, and identifies damage requiring a replacement, the costs can range from £300 – £450 for a replacement component inclusive of labour. Due to the costs involved, it would be worth having a discussion with the engineer as to whether a replacement boiler would be more economical.

Related reading: 

• Boiler leaking water from the bottom.
• How to reduce your boiler pressure.
• How to reset your boiler.
• Central heating pump problems.

#4 Boiler Keeps Locking out

There is a safety mechanism built into most brands of boiler to lockout if an issue is detected, to protect not only the internal parts but also the property that the boiler is located within.

However, some Baxi boilers are more prone to lockout issues than others, such as the Baxi Solo 1PF and 2PF models. Often the cause is due to overheating and therefore the lockout is to prevent a fire or further damage to the internal components.

There is a range of issues that can cause overheating within boilers. Some of the common issues should show the following Alpha boiler fault codes within the display window:

• Fault code 110 – Overheating
• Fault code 160 – Faulty fan
• Fault code 166 – Air pressure switch fault

Overheating can be caused by low pressure within the boiler. A suitable pressure level for a Baxi boiler is 1.5 bar, therefore if the pressure reading is lower than this you can top up the pressure. The process of topping up the boiler pressure will be detailed within the boiler’s user manual, however, is often completed via using the filling loop located underneath the boiler. Once the pressure is at the appropriate level, the next step would be to reset the boiler and wait to see if the matter is resolved.

If the boiler loses pressure again, another issue is at play causing the loss of pressure, such as a leak. In this scenario, it would be best to check the entire heating system for any evidence of leaks and call out a professional heating engineer for further guidance.

#5 Ignition Issues

Boiler lockouts can also be caused by ignition problems. Unfortunately, Ignition concerns are frequently seen within some Baxi boilers including the Baxi 100E and 105E models.

The lockout is to ensure the safety of the boiler and household, that no gas can escape.

This issue would need to be escalated to a qualified Gas Safe engineer to undertake tests on the boiler to find the cause of the ignition issue, which could include faulty gas valves or seals. If a smaller component is found to be the source, a replacement should not be too expensive however if larger parts are at fault the costs can soon ramp up and again, it would be worth discussing a boiler replacement with the engineer.

Boiler brand faults: 

• Common Biasi boiler faults.
• Ariston boiler problems.
• Vokera boiler faults.
• Baxi boiler problems.
• Alpha boiler problems.
• Worcester Bosch boiler problems.

Baxi Boiler Problems Conclusion

Even the most reliable boilers can become faulty and cause breakdown issues. Hopefully, this guide has provided oversight of the most common issues that occur with Baxi boilers and advise the next steps to get the boiler working again.