When the air temp in my house rises to the target for the radiant system, the 'mix target' temperature for the water drops low, but the circulating pumps still run.   Is this OK?  It seems like the circulating pump runs all the time, regardless of whether heat is being added to the radiant circuits.  It's a viega basic heating control, and a grundfos pump.



Thanks

What's the set-up?  More detail needed; is there a slab w. a sensor?

Sounds like it is working on outdoor reset and yes the pump may run part or all of the time. A question for your designer I think.

There are air temperature sensors in the basement and 1st & 2nd floors - no slab sensors.