Vaillant F28 Boiler Error/Fault Code

If your boiler displays an F28 Error/Fault Code, it either has an ignition problem or a gas valve fault. To learn about the issue in detail and its causes, make sure you read the blog until the end!

What Does F28 Mean on a Boiler

If you have Vaillant boiler models, e.g., Vaillant ecoTEC Pro, ecoTEC Pro Plus, Turbomax Plus 824/828E, the fault code F28 indicates ignition faults or issues with the gas valve. The fault code will be displayed when your boiler fails three ignition attempts. The error code is a safety mechanism that halts operation if one of the boiler’s components is malfunctioning.

The ignition is essential as it lights up the gas, creating a flame that heats the cold water supplied throughout your home. The gas valve monitors the flow of gas within the boiler. So, if one of these critical components isn’t functioning as it should, it displays the fault code to protect you from potential malfunctions that put your safety at risk.

Reasons Behind the F28 Fault Code

Problem #1: Gas Valve Fault

The gas valve is a crucial component that controls the gas flow within your boiler. If it fails, it affects the boiler’s functionality and efficiency. The fault in your gas valve occurs mainly due to mechanical and wiring issues.

The Mechanical fault occurs due to wear and tear, which causes the valve to stick during operation. This results in difficulty opening and closing the gas valve when gas is needed to supply your boiler.

Another reason for a faulty gas valve is a loose wiring connection. As we all know, all boiler components are connected through wiring to the boiler’s PCB, which is the heart. So, if the wiring connection between your gas valve and PCB is loosened, then your PCB won’t reach the signals, and your gas valve will malfunction.

Possible Solution for Mechanical Fault:

To solve this issue, you will need to replace the gas valve, which will cost you around £100-£200 for the valve and £150-£300 for the labour.

Possible Solution for Wiring Issue:

To solve your wiring issues, you will need to contact a certified professional who will inspect the wiring and fix the loose connections; this will cost you between £180 and £500.

Problem #2: Frozen Condensate Pipe

A condensate pipe carries the wastewater outside your home that is produced by your boiler during combustion. During winter, the condensate pipe freezes, causing a blockage that prevents drainage. Due to this, the boiler halts its operation and displays an error code.

Possible Solution:

To solve this issue, you will need to defrost the frozen condensate pipe. To do that, you will need to locate the area of blockage, pour warm water on it, and then restart your boiler.

Related Articles:

• How to Defrost Frozen Condensate Pipe
• The Boiler Condensate Pipe is Blocked!
• My Pipes have Frozen Help!

Problem #3: Fault with the Boiler’s PCB

The PCB is the heart of your boiler, acting as a control centre that ensures all the components are working seamlessly. If any component fails to transfer the signal to the PCB, it will display an error code and halt the boiler’s operation for the time being. A faulty PCB could be due to loose wiring connections or a manufacturing defect.

Possible Solution:

As mentioned above, contacting a certified professional can solve the wiring issue, costing between £180 and £500.

However, if the PCB is damaged due to a manufacturing or installation defect, you must replace it altogether, which will cost between £350 and £500, excluding the installation cost. So, if the PCB gets damaged, investing in a new boiler is more logical.

Problem #4: Damaged Electrode

The electrode ignites the flame when gas enters the boiler through a gas valve. Over time, these electrodes become damaged due to wear and tear and need to be cleaned or replaced.

Possible Solution:

Contact a gas-safe registered engineer who will replace the electrode if it is too worn out. This will cost you around £100 to £300.

Problem #5: Low Boiler Pressure

Another reason the F28 error code is displayed is low boiler pressure. Low boiler pressure could be related to multiple reasons: you have recently bled your radiator, or there are leaks in the pipework.

Possible Solution:

If you have identified leaks near your boiler, immediately contact a gas-safe registered engineer. If you have bled your radiators recently, you can re-pressurise your boiler via a filling loop.

Related Article: How to Increase Your Boiler Pressure.

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Final Thoughts

After reading the above, you will know the reason behind the Vaillant boiler F28 fault code and the possible ways to solve it. Throughout the blog, you will realise that to solve this problem, you will need the assistance of a certified professional.

Although scheduling an annual boiler service helps you identify these problems in advance, if the problem persists and your boiler gets old, investing in a new boiler might be the right choice.

If you want to know more about similar fault codes for your Vaillant boiler, read our blog, Vaillant Boiler Fault Codes. If you require any assistance or have queries, please get in touch with us on 0345 0774 177, and one of our representatives on call will assist you and help solve your problem.