Vaillant F.26 Fault Code
Meaning of Fault: Gas valve without function
What this means is that the detection of the stepper motor is not taking place. This could be caused at the source, which is the PCB being at fault by not issuing the correct voltages. Can be caused in the transmission cables ie the harness cables and connectors etc or finally it could be the stepper motor at fault itself.
Vailant’s own meaning says: Gas valve stepper motor not connected, multiple plug on the PCB not plugged in correctly, interruption in cable harness, gas valve stepper motor defective, electronics defective
Part numbers for Gas Valves:
Following is a list of Gas Valve part numbers for a range of Ecotec boilers.
0020148381 Gas Section with Regulator. Used in: Ecotec Plus 612, 615,618,624,630; VU XXX/5-5, VU XXX/5-5 R1, VU XXX/5-5 R2, VU XXX/5-5 R4