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New radiant install

Rich_L Member Posts: 77
I just completed a new house radiant install. There are 9 zones, 2 seperate loop temps, outdoor reset, mod-con boiler with an indirect water heater. Just finished last Friday and things were really comfortable today! I love doing these systems!


  • Very Pretty

    Two separate loop temperatures?  Staple-up and in-slab? Radiators and radiant? What kind of tempering valve did you use?

    Your solder joints look perfect and I can't see anything out of level. 

    I'd say it took you 5 working days to do that by yourself.  It would take me longer and I'm embarrassed to say it wouldn't look as good.
    Often wrong, never in doubt.
  • DJS
    DJS Member Posts: 4

    This is why I do this. I just love the look of a great piping job. Great job  hope you have many a comfortable days!!!!
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    Question about two loop temperatures.

    I have a radiant slab at grade for one zone and oversized fin-tube baseboard for my other zone. Also an indirect hot water heater. I, too, have a W-M Ultra.

    Because of the way things worked out, I just use the three thermostat inputs. Priority 1 runs the indirect. Priority 2 runs the slab, and priority 3 runs the baseboard. The U-control can drive only three circulators, so I have another relay to take care of the baseboard zone. The baseboard uses a constant temperature (175F for me), and the two heating zones use different reset curves.

    The way things work, if the radiant zone is getting priority, I use the radiant reset curve. If the baseboard wants heat too, it gets it, but only at the temperature demanded by the radiant zone. If the baseboard has priority, it gets the higher temperature its reset curve demands and the cirulator to the radiant zone is cut off. Because the heat load for the baseboard zone is low, and the baseboard is so oversized, this works very well.

    I imagine most homes would not work out so nicely, and that the higher temperature reset curve would be needed at all times, and that the lower temperature zone would need to be served by a temperature mixing valve.

    Which approach did you manage to use?
  • Rich_L
    Rich_L Member Posts: 77
    edited December 2011
    Two temp system

    Thanks for the kind words! Many years ago a journeyman I apprenticed under told me you should be willing to "sign your name" to every job you do. I take pride in how my job looks as well as how it works. I know many here do the same!

    Alan, it's a staple up and in slab job. The slab is below grade (basement floor) and has a very steady heat loss. Simple to do with a Honeywell AM101R-US-1 mixing valve.

    DJS, Thanks, unfortunately not my house but hopefully many comfortable days for my customer!

    JDB, Indirect has priority. The staple up needs the higher temperature so it runs on the reset curve of the Ultra, the in slab has a very steady heat loss since it's a basement so I mix down to a set temp. 85 degrees water temp handles out -5 degree design temps in my area (Iowa). The mixing valve gives a steady set temperature regardless of the staple up temp. I've done these before for slab on grade with higher heat loss, with a Tekmar control and 3 way mixing valve for out door reset for two different temp circuits. I used to do injection loops with Tekmar control but that was before condensing boilers became popular.

    Thanks again, Rich
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