The F27 Fault Code on Vaillant Boilers: Causes and Solutions
The F27 Fault Code on Vaillant Boilers: Causes and Solutions

The F27 Fault Code on Vaillant Boilers: Causes and Solutions

The F27 Fault Code on Vaillant Boilers: Causes and Solutions

If your Vaillant boiler is displaying the F27 fault code, don't worry, it's not uncommon. In this article, we'll explain what this error code signifies and provide possible solutions.

All Vaillant boilers come equipped with error codes to notify homeowners of any issues and provide information about the nature of the problem. Each code has a unique meaning, which can be found in the Vaillant manual.

Some faults can be easily fixed at home, while others require the expertise of a professional. In the case of the F27 fault code, here's what you need to know.

What Does F27 Mean?

The F27 fault code indicates an incorrect flame detection. In simple terms, it means that the balance between the gas and flame is not appropriate for the boiler to function normally. This error code is exclusive to the Vaillant ecoTEC Pro and Plus boilers and will cause the boiler to shut down, preventing access to heating and hot water.


The Causes of Gas and Flame Imbalance

The F27 fault code can stem from a variety of reasons, and the resolution will depend on the particular cause. These are some of the most frequent explanations:

Moisture on Electrical Parts

 A buildup of moisture on electrical components can lead to the F27 fault code, which could be the result of a leak or a problem with the heating system.

Gas Valve Malfunction

 The gas valve is responsible for regulating the amount of gas that enters the boiler. If the gas valve is faulty, it may result in inadequate or no gas reaching the boiler, leading to the F27 fault code.

Worn Ignition Leads or Spark Electrode

 Over time, the ignition leads or spark electrode can wear down, leading to incorrect ignition of the flame, and resulting in the F27 error code.


PCB Failure

 A failing printed circuit board (PCB) can cause a variety of problems, including inadequate temperature regulation, a pump or fan issue, or a flashing display panel. A malfunctioning PCB can also trigger the F27 fault code.

Flame Sensor Issue

 Although it's possible, it's unlikely that a flame sensor problem could lead to an F27 error code. This is because the flame sensor plays a critical role in maintaining the proper balance between gas and flame.


Is DIY Repair of F27 Error Possible?

DIY repair of an F27 error is not recommended or allowed by law. It is important to hire a Gas Safe Register engineer to resolve the issue. Not only is it a requirement by law, but it is also critical for safety reasons.

If you suspect a leak to be the cause of the F27 error, it is recommended to turn off the water supply until a professional arrives. Attempting to repair the issue yourself could potentially be dangerous and is not advised.


Cost of Repairing an F27 Error with a Heating Engineer

The cost of hiring a heating engineer to fix an F27 error code varies depending on the nature of the repair. On average, Gas Safe Register engineers charge around £30 to £60 per hour for labour. However, this is just an average and the cost of labour can vary based on factors such as location.

Here is a rough estimate of the cost of fixing an F27 error:

Cleaning/Repairing Electrical Components - £80 to £200. Repairing or Replacing a Gas Valve - £160 to £320. New Ignition Leads - £50 to £170. Replacing a Spark Electrode - £40 to £160. PCB Replacement - £330 to £730. Flame Sensor Repair or Replacement - £40 to £150. Boiler Replacement - £800 to £2,800.

It's important to note that these costs are general estimates and may vary depending on the extent of damage and cost of parts. Additionally, if the cost of repairing the PCB is high, it may be more economical to replace the boiler instead. Some people may choose to finance a boiler replacement if needed.

It's always best to consult a professional for a more accurate estimate and to ensure that the repair is done safely and properly.

Will My Warranty Cover Repairs for an F27 Fault Code?

The warranty on a Vaillant boiler applies only to repairs resulting from a manufacturing defect. If the F27 error is caused by something other than a defect in the boiler's manufacturing, the warranty will not cover the necessary repairs or replacement.

Additionally, even if a manufacturing error is the root cause of the F27 fault, you should verify that your boiler warranty is still active. The standard warranty for a Vaillant ecoTEC Plus boiler is five years, but it can be extended to seven years if installed by a qualified professional. For the ecoTEC Plus range, the standard warranty is two years, but it can also reach seven years with the proper installation.

It's essential to note that these warranties come with specific terms and conditions, such as the requirement for annual servicing by a Gas Safe Register engineer. So, it's unlikely that your warranty, if you have one, would cover the repair of an F27 error.


Do you need help with a common error code on your Vaillant boiler? Look no further, as we have comprehensive guides on various Vaillant boiler fault codes.


Vaillant F22 Error Code.

Vaillant F23 Error Code.

Vaillant F24 Error Code.

Vaillant F25 Error Code.

Vaillant F27 Error Code.

Vaillant F28 Error Code.

Vaillant F29 Error Code.

Vaillant F54 Error Code.

Vaillant F62 Error Code.

Vaillant F72 Error Code.

Vaillant F75 Error Code.

Vaillant F76 Error Code.

Vaillant F83 Error Code.


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At Zara Heating, we understand the importance of having a well-functioning heating system, especially during the colder months. That's why we strive to provide the highest quality of service to our customers and ensure their Vaillant boilers are installed and running smoothly. Our team of highly skilled and certified technicians are experts in Vaillant boilers and have years of experience in providing top-notch installations and replacements.

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