Purchased a Wiser system over two years ago in anticipation of using Opentherm when the old boiler was replaced. I then had the boiler replaced with a Vaillant Ecotec Plus 430. I also purchased from the Netherlands a Vaillant Opentherm module but never installed it as I then discovered that the Wiser Opentherm option was allegedly only compatible with combi boilers.

Is anybody running a Wiser system with Opentherm using a system boiler?