F.26 — Fault: Gas valve without function

What does F.26 mean?

The boiler has detected that the gas valve is not functioning correctly, which prevents it from regulating the gas supply to the burner.

• Gas valve stepper motor is not connected.
• Multiple plug on the PCB is not correctly plugged in.
• Interruption or damage in the cable harness for the gas valve.
• Gas valve stepper motor itself is defective or the main electronics are faulty.

Click steps to track your progress.

1. 1

   Press the fault clearance key on the boiler to reset it.

2. 2

   Visually check any accessible electrical plugs and connections for the gas valve.

3. 3

   If the fault persists, contact Vaillant Service Solutions, as this involves the gas supply system.