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A Comprehensive Guide to Solve the F28 Error Code in Your Vaillant Boiler

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A Comprehensive Guide to Solve the F28 Error Code in Your Vaillant Boiler

One common problem faced by users of Vaillant boilers is the error code F28. If you’re encountering this error on your Vaillant boiler, there’s no need to worry – in this blog we will discuss the causes of the F28 error, troubleshooting steps you can take, and when it’s time to call in the certified engineers.

Understanding Error Code F28:

The F28 error code of the Vaillant boiler indicates a problem with ignition. Essentially, the boiler has failed to ignite, leaving you without heating or hot water. This issue can stem from various underlying factors, ranging from simple fixes to more complex technical problems.

Reasons for Error Code F28:

  1. Deficiency of gas supply: One of the main reasons for the F28 error, is a disruption in the gas supply to the boiler. This could be due to a closed gas valve, low gas pressure, or issues with the gas meter.
  2. Damaged ignition system: A malfunctioning ignition conductor, faulty ignition lead, or ignition PCB can prevent the boiler from lighting properly, which causes the F28 error.
  3. Air intake blockage: If the air intake pipe is blocked or restricted, it can hinder the ignition process, leading to ignition failure and the F28 error.
  4. Electrical issues: Problems with the boiler’s electrical connections, such as loose wires or damaged components, can also contribute to error code F28.
  5. Water in the Boiler or the Flue Duct: This may occur after heavy rain when the water enters through the flue duct and the boiler is full of water

Troubleshooting Steps to Fix This Issue:

Before contacting a professional, there are numerous steps you can take yourself to resolve the F28 error on your Vaillant boiler:

  1. Check the gas supply: Confirm that the gas valve supplying the boiler is working and that there are no issues with the gas meter or supply line.
  2. Reset the boiler: Try resetting the boiler by switching it off, waiting for a few minutes, and then turning it back on. This can sometimes clear temporary faults.
  3. Inspect the air intake: Check the air intake pipe for any blockages. Clear away any debris that may be hindering airflow to the boiler.
  4. Restart the ignition process: Follow the manufacturer’s instructions to manually reignite the boiler, ensuring that the ignition system is functioning properly.


Facing the F28 error code on your Vaillant boiler can be frustrating but with the right knowledge, you can troubleshoot the problem effectively. If you are not able to fix this issue despite all troubleshooting efforts, contact us to seek help from our professional gas engineers who are competent to effectively fix any boiler related issues.

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