Viessmann programming

Alan (California Radiant) Forbes

The Vitodens 200 programming has a field, "Setting Room Temperature" that you can adjust to your desired room temperature. I really don't understand how this works since there is no indoor temperature sensor for any kind of feedback, just an on-off thermostat, i.e. there is no way it knows what the room temperature is. And in order for it to work, it would have to adjust either the reset ratio or the parallel shift, no?

iix

My understanding is that the room temperature setting is for short term adjustments to the reset curve. You would want to set your curve with the slope and shift settings then the room temperature setting is used for set backs.

GW

Yes it's a baseline number without indoor sensing. 20c or 68f is the normal. Turn it up and your entire slope and or shift rises as well, making more heat. Turn it down and vise versa. The three settings you mention are independent. The boiler is intended for constant circulation

Gary

Paul Pollets

The Vitodens 200 will accept a Vitotrol 300 or 200 thermostat, which has an internal sensor that can be enabled by coding. If you're not using one, a regular thermostat is not best for the application as a regular T-stat will stop the continuous circulation. Your heating curve needs to be in the ballpark and the Viessmann thermostats will actually change the heating curve, without having to adjust the boiler computer.

Alan (California Radiant) Forbes

Thanks, you guys! Very helpful!

GW

Paul Pollets said:

The Vitodens 200 will accept a Vitotrol 300 or 200 thermostat, which has an internal sensor that can be enabled by coding. If you're not using one, a regular thermostat is not best for the application as a regular T-stat will stop the continuous circulation. Your heating curve needs to be in the ballpark and the Viessmann thermostats will actually change the heating curve, without having to adjust the boiler computer.

yes just need to play with the b2 setting!!