UFH mixing valve setting

[Johnnyt]

I have a 20kW Viessman system boiler on a 4 pipe system for DHW and UFH.

There is a mixing valve at the UFH manifold that seems to be at odds to the indicated flow temp on the boiler and measured flow temp on the manifold.

The boiler readily modulates down to 2kW and cycles approx every 35 mins.

The boiler is quite sophisticated and I can have 3 different flow rates for different times of the day. I do not have weather comp.

Is there any value in say setting the UFH mixer to say 50c, so in effect permanently open and just let the boiler regulate the flow temp which is presently at 37c.

The flow temp on the boiler does match the temp on the hot side of the manifold when the mixer is set high and I have a deltaT of 8c with five zones controled by in room wall mounted programmer/stats.

 

Edited December 14, 2023 by Johnnyt