Viessmann 200W - no modulation below 17%

[Apprentice]

Dear All, I have a Viessmann 200W (last year model, 7 inch color display) and out of nowhere it does not modulate under 17% anymore, making it unusable. (underfloor heating, external module getting commands from 3 distributors, running the system at around 30 degrees, and because of the high modulation the temperature rises and the boiler shuts off).  Commands, everything else seems to work - any thoughts as to what I could look for?

Thank you for any suggestion and all the best!

[Apprentice]

Sorted it out.  One setting in commissioning menu (in connection with the connection to the chimney) was wrong. 

[RaduB]

Hello!

I have the same issue. Can you please tell me which setting you modified to resolve this problem?

thank uou!

[Apprentice]

Hi, it only works if you start the commissioning process again.  One of the settings (on the first screens, where you have type of house, etc) refers to the connection of the boiler to the chimney: one boiler to the evacuation system or several boilers to the same evacuation system.  i got no modulation under 17% in case the option with several boilers was (wrongfully) selected. Hope it helps.

[RaduB · Accepted solution]

thank you very much. resolved