Thank you for the reply. Do you know if there is a threshold for the proportional control which switches the boiler relay?

I have Domoticz running on Windows connected to a HGI80. The boiler is controlled by the relay BDR91. I am interested in Boiler demand and saw that Dompticz has two devices "Boiler" and "Relay", one ( or both) of which I assumed controlled the Boiler relay. I had expected to see a binary on/off ...