Mixing valve position

Thom Masse (rookie)

We installed one zone of radiant in a bathroom. We came off the boiler to a mixing valve (honeywell), air scoop w/expansion tank, Grundfurd circulator, and on to the feed PEX. The radiant panels are Roth, a large shower pan sits on one end of the room (7'x4'). We run that zone and get 80 degree return temp., and falling. Should it take "days" to become natural operating temprature?
On the return, it runs through a draw-off, ball valve, to a tee one to the boiler the other through a Temp. gauge and back to the mixing valve. The return is cold should it go to the cold of the valve or to the mix of the valve?

Radiant Wizard

How about a piping diagram

Why is there an air scoop and expansion tank. If this is off a boiler you don't need to add those things to the zone. Sounds like there are a couple of things going wrong here.

Weezbo

hmmm...

there are a few variables......is the room insulated with the windows and doors installed in the walls? .....next thought is do you allow the cold a checked path ,on the return to the boiler and a path direct to the cold side of the mixer? did you purge the air out of the lines? for starters.

Mark Eatherton1

Who's boiler

what pump? Any other loads connected?

ME

Thom Masse (rookie)

Thanks guys! What a place to learn from! Yeah, there is a chech valve on the boiler side of the tee. Lot of variables,yes. But our return is connected to the cold side of the mixing valve. That is an "in" port. If I'm thinking right. I offered my stupidity to my boss, told him about "the wall" and the replies I got, we are going to change things. In my readings in PM magazine, I've learned a few things. And knowing you guys are here. We are all to benefit.