Vaillant F28 Fault

Vaillant F28 Fault

The Vaillant F28 error code signifies a failure to ignite, which can be a common issue affecting the operation of your boiler. This problem can arise for several reasons, ranging from issues with the gas supply to faults within the boiler’s ignition system. Understanding the causes behind this error code is crucial for troubleshooting and resolving the issue to restore your boiler to normal operation.

Causes of the F28 Error Code

  1. Gas Supply Issues: A lack of gas supply due to closed gas valves, unpaid bills, or supply disruptions in your area can prevent the boiler from igniting.
  2. Ignition Problems: Faults with the ignition system, including failed ignition leads, electrodes, or problems with the ignition sequence, can lead to ignition failure.
  3. Blocked Burner or Flue: A blockage in the burner or the flue system can interfere with the proper mixture of gas and air, hindering ignition.
  4. Low Gas Pressure: Insufficient gas pressure can prevent the boiler from igniting properly. This could be a problem with the household supply or the boiler settings.
  5. Faulty Components: Components like the gas valve or the printed circuit board (PCB) that are malfunctioning can lead to ignition issues.

Troubleshooting and Resolving the F28 Error Code

  1. Check Gas Supply: Ensure that your gas supply is on and that there are no wider supply issues in your area. Check other gas appliances to confirm they are working.
  2. Reset the Boiler: Attempt to reset your boiler according to the manufacturer’s instructions. This can sometimes clear temporary faults and allow the boiler to ignite.
  3. Inspect for Blockages: Look for any visible blockages in the burner or flue that could be cleared. However, significant blockages or issues with the flue should be addressed by a professional.
  4. Monitor Gas Pressure: If possible, check the gas pressure to ensure it is at an adequate level for ignition. Adjusting the gas pressure should be done by a qualified professional.
  5. Seek Professional Help: For issues like faulty ignition components, low gas pressure, or if you are unable to identify the cause of the F28 error, it’s advisable to contact a Gas Safe registered engineer. They can safely diagnose and repair faults within the ignition system or other critical components.


The Vaillant F28 error code indicating a failure to ignite requires prompt attention to ensure the efficient and safe operation of your boiler. While some checks can be performed by the homeowner, many causes of this error code necessitate professional diagnosis and repair. Regular maintenance and servicing by a qualified technician can help prevent such issues and ensure your boiler remains in good working condition.