Setting up Tado Extension Kit with Vaillant EcoTec Plus 938 boiler


Hi all

I hope someone could shed some light on this for me

I'm trying to set up my Tado Extension Kit with a Vaillant EcoTec Plus 938 boiler and connecting the cables – as the installation manual – to the BUS connections to the right of the 24V RT connection

When I switch the power to the boiler back on nothing happens with the  Tado Extension Kit , no power, no flashing lights, nothing!

Has anyone else had this problem? If so, have they managed to fix the issues?