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Viessmann vitotronic mixing valve--- not needed????

CBRob Member Posts: 273
edited November 2019 in THE MAIN WALL
Was studying the manual for the vitotronic mixing control.
It seems to be just another lever of outdoor reset curve..
It's more adjustable by room temp and day vs night...
It has to use water from the boiler that is hotter than the desired supply temp, which is counterproductive when seeking a lower boiler temp for efficiency.

Spent a couple more hours reading the manuals.
This mixing control is for heating 2 different types of zones at the same
Time. Like a radiator at 140 and a thin slab at 100, you'd mix
The slab water to cool it down.
I have no idea what its doing in my system. I have gypcrete zones only,
And some dhw and snowmelt that are on other loops and a HX.
I'm considering setting the valve to a fixed position and disabling the control.


  • CBRob
    CBRob Member Posts: 273
    edited November 2019
    Pic of the return lines feeding the mixing valve.
    Drawing from the return line as well as from the other end of
    The supply manifold.