Opentherm to Bosch EMS

[speedychuck]

Hi,
New to the forum, although a returning member to the evohome shop. I think I was actually the first person to buy an opentherm interface from the evohome shop.

Anyway, I've just moved house and taken the evohome system with me. I've gone from an ideal logic combi, to bosch greenstar system boiler.

From my reading, I need to get an opentherm to EMS converter for the Bosch. I was just wondering if there is a uk supplier, as I they all seem to be in Holland. Also, I was wondering if anybody had experience with this and evohome.

Thanks!!

[Richard]

Hi, and Welcome.

As far as Worcester Bosch goes, they won't allow these converters to be officially used, as they are not made by Bosch and have therefore not been certified. That being said, I believe they do work. Holland is the only option for supply, as rules are different there and manufacturers get paid for allowing OpenTherm to be used on their appliances.

I hope that helps and let us know how you get on.

[XAPPO]

I am interested how you got on with using EMS with openTherm - did you try the convertor?

I have a 24 TRV evoHome system but would really like to install a WB boiler. I could replace the whole evoHome system with WB EasyControl (or perhaps drive it in on/off mode?) but I've been happy with evoHome and EasyControl doesn't yet support mechanical zoning valves.

I'm also looking at the other EMS interface that allows bus snooping and integration with MQTT / Home Assistant and then maybe kludging the evoHome demand signaling into EMS. That would be an interesting project but something I think would fall foul of my time availability.

Also were you happy with ideal as I am considering the ideal Evomax2 possibly in cascade.

[Lukefree233]

Not wanting to start a new thread about Bosch to Opentherm.

Just reinstalling a system in our new house and wondering if anyone has used the Bosch EasyControl Adapter (EMS converter to opentherm) - Part number7 736 701 560.

I'd quite like to use Opentherm control on the new system when the R8810 is available again and this seems to be the official replacement for the Nefit adaptor. I've not seen much about the adaptor but I didn't want to purchase one with the R8810 and find out its not going to give me any benefit over the std. non-Opentherm control or be troublesome in operation.

Thanks.

[Richard]

Not wanting to start a new thread about Bosch to Opentherm.

Just reinstalling a system in our new house and wondering if anyone has used the Bosch EasyControl Adapter (EMS converter to opentherm) - Part number7 736 701 560.

I'd quite like to use Opentherm control on the new system when the R8810 is available again and this seems to be the official replacement for the Nefit adaptor. I've not seen much about the adaptor but I didn't want to purchase one with the R8810 and find out its not going to give me any benefit over the std. non-Opentherm control or be troublesome in operation.

Thanks.

People misunderstand what this adaptor does. It allows Bosch's EasyControl system to work with OpenTherm, not the other way around. So therefore unfortunately, nothing like the Nefit adaptor.

[wisniol]

I live in Poland. I bought a Nefit EMS-OT Converter in the Netherlands.
It works perfectly with my Buderus Logamax plus GB072(K)V2 (EMS protocol communication, Bosch group).
To put it very simply, my configuration:
Honeywell Evohome -> Honeywell R8810A1018 -> Nefit EMS-OT -> Buderus boiler.