Vaillant F22 Fault

Vaillant F22 Fault

The Vaillant F22 error code indicates a problem related to low water pressure within the boiler system. This situation can arise for several reasons, including leaks in the heating system, recent radiator bleeding, or natural pressure loss over time. The low pressure prevents the boiler from operating safely and efficiently, necessitating prompt action to rectify the issue.

Causes of the F22 Error Code

  1. Leaks in the System: Small leaks anywhere in the heating system can gradually reduce water pressure.
  2. Bleeding Radiators: After bleeding radiators to remove trapped air, the system can lose water and, consequently, pressure.
  3. Natural Pressure Loss: Over time, it’s normal for a heating system to experience slight pressure decreases.

Troubleshooting and Resolving the F22 Error Code

  1. Check for Visible Leaks: Inspect the heating system, including radiators, pipes, and boiler, for any signs of leaks. If you find a leak, it will need to be repaired.
  2. Repressurize the Boiler: Most Vaillant boilers have a built-in filling loop that you can use to repressurize the system. The correct pressure level is usually around 1.0 to 1.5 bar, as indicated on the boiler’s pressure gauge. Follow the manufacturer’s instructions to safely repressurize your boiler.
  3. Bleed Radiators: If you haven’t recently bled your radiators, trapped air in the system could be contributing to the pressure issue. Bleeding the radiators can help restore normal pressure levels.
  4. Reset the Boiler: After addressing the pressure issue, reset the boiler according to the manufacturer’s instructions to clear the F22 error code and resume normal operation.
  5. Monitor the Pressure: After repressurizing the system, keep an eye on the pressure gauge to ensure that the pressure remains stable, indicating no further leaks or issues within the system.
  6. Seek Professional Help: If you’re unable to identify the cause of the low pressure, the pressure drops again shortly after repressurization, or you’re uncomfortable performing any steps, it’s advisable to contact a Gas Safe registered engineer for professional assistance.


The Vaillant F22 error code is a common issue that can often be resolved by repressurizing the boiler system and checking for leaks. Regular monitoring and maintenance can help prevent pressure-related problems and ensure your boiler operates efficiently and safely. If in doubt, always consult a professional to address any boiler issues.