Vaillant F62 Fault

Vaillant F62 Fault

The Vaillant F62 error code signifies a problem with the gas valve shutoff delay. This fault occurs when the gas valve in your boiler fails to close within the expected timeframe after the burner has been turned off. This delay can pose safety risks, as it implies that gas could continue to flow or leak into the combustion chamber when it should not, potentially leading to unburned gas accumulating.

Causes of the F62 Error Code

  1. Faulty Gas Valve: The gas valve may be malfunctioning or stuck, preventing it from closing promptly. Wear and tear or mechanical failure can cause this issue.
  2. Electrical Faults: Problems with the electrical circuit controlling the gas valve, such as faulty wiring or a malfunctioning printed circuit board (PCB), can impair the valve’s operation.
  3. Control System Errors: The boiler’s control system, including the PCB, may be issuing incorrect commands to the gas valve, leading to delayed shutoff.

Troubleshooting and Resolving the F62 Error Code

  1. Immediate Action: Given the potential safety risks associated with gas valve issues, it’s advisable to turn off the boiler and contact a Gas Safe registered engineer immediately. Do not attempt to fix this issue on your own.
  2. Professional Inspection: A qualified technician will need to inspect the gas valve and associated electrical components to diagnose the cause of the delay. This inspection may involve testing the gas valve’s operation, checking the wiring, and evaluating the PCB.
  3. Repair or Replacement: Depending on the diagnosis, the solution may involve repairing or replacing the faulty gas valve, fixing electrical connections, or addressing issues with the boiler’s control system. Only a professional should perform these repairs to ensure they are done safely and correctly.
  4. System Check: After any necessary repairs or replacements, the technician should check the entire system to ensure it’s operating safely and efficiently. This check will confirm that the gas valve closes as expected and there are no leaks or other safety concerns.
  5. Regular Maintenance: To prevent future occurrences of the F62 error and other potential boiler issues, ensure your heating system receives regular maintenance from a qualified professional. Annual servicing can help identify and address wear and tear before it leads to significant problems.


The Vaillant F62 error code indicates a serious issue with the gas valve’s shutoff timing, requiring immediate professional attention. Due to the potential safety hazards associated with gas leaks or unburned gas accumulation, homeowners should not attempt to resolve this issue themselves. Regular boiler maintenance by a Gas Safe registered engineer is essential for identifying potential problems early and ensuring the safe operation of your heating system.