I am upgrading my old Ariston boiler to Vaillant ECOTEC/PRO VCW 286. I have been using Tado for a few years and unfortunately got zero help from Tado's customer care. Some input would be appreciated with regard to installing/wiring
Hopefully this thread will help. Wire the extension kit to the ebus connector and make sure you change the settings on the smart thermostat.
Only thing I can think is check you have the HW option in the setup correctly set.