The Efficient Home Forum

After a number of years of ignoring the problem of my radiators being set to max / off by the boiler and opentherm, I’m wondering if going back to the simple on/off boiler control via a BDR91 would be better? This was my original plan as the boiler was installed by the previous owner and has an exte...

I just came across this thread, and having a Vitodens 100 connected with an OpenTherm wireless bridge to to evohome, I thought I'd share my experiences: - yes, the boiler goes up to 81 - 82 degrees and that value can not be changed on the boiler (afaik), - I also reduced the maximum heating input (...

Update on my setup - it all works! Viesmann Vittodens 100W boiler - heating controlled by opentherm bridge, as well as existing viesmann weather comp sensor. Hot water controlled through BDR91 acting as a relay switch wired into the Viessmann Cylinder Demand box and boiler trigger input. Existing Vi...

Thanks Richard Some follow-up questions on 3 and 4 3 - I don't have any external valves for the hot water. The boiler has its own separate feeds/returns for hot water and heating. I'm hoping opentherm can call for either water or heating as I'm not sure where I would wire the BDR into. 4 - comments ...

I have purchased the wifi boiler control and hot water controllers (Connected Thermostat Pack ATP921R3100 and ATF500DHW Hot Water Kit) and am now trying to wire up these to the boiler. A few questions / looking for advice: 1 - am I better wiring the controllers up using the BDR91 relays that come wi...