Hi All,
I have and very old boiler (kessell) Vitodens 200 WB2, first model. This was installed in my house in 2004 in the UK and KNX bus was installed back then. in the UK, KNX isnt really used. Viessmann UK dont really know anything about KNX gateways. The KNX included a heating actuators to radiators. There is only one heating circuit and DHW. I eventually installed the KNX gateway to control this boiler. The boiler does has weather compensation. I thought the system was 'dumb' as it appears if you dont have a seperate heating circuit, with a seperate heating pump, then the gateway cant turn on or off the internal heating pump. I dont have under floor heating, not a lot of people have underfloor heating in the UK. I managed to get it to work to transfer data to KNX, change heating curves and slopes, change the main set point temperature. Anyway, the boiler is 20 years old and is getting old and it is time to replace it with a new Vitodens 200. I will have to replace the the KNX gateway when I change the boiler but once again, I think it will be a 'dumb' gateway and they are nearly 900 EURO.
What is the benefit of using the KNX gateway, with just weather compensation? Has anyone used OPENTHERM? Theben make a opentherm gateway, and does appear that it can use the actuator/temp sensors to control heat demand from the boiler, rather than the viessman knx gateway. Also the theben opentherm gateway only costs 250 euro.
Any thoughts from anyone?
Many Thanks Nigel from the UK
