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  1. #1
    I have an addition to a school building that will be housing kindergarten kids. The main school has a hot water boiler that will be generating between 130 F to 190 F to provide hot water heat to perimeter fin tube radiators. I want to use water off of this boiler to also heat the radiant floor. However, the floor heat should be maintained between 90 F and 120 F... a lot lower than the rest of the system. I thought about adding a mixing valve to lower the water temperature, but no matter how much water gets diverted with the mixing valve, the water temperature being supplied to the floor will still be too hot. The simpler, the better. I could use a heat exchanger and additional circulation pump for the radiant floor, but don't want to make it that complicated. Does anyone have any ideas of how I can reduce the temperature to the radiant floor?

  2. #2
    the water temp will be too hot even if you mix the return water? have piped a few where the return water supplies the radient floor and is supplemented by mixing hot supply water on really cold days when return temp on loop is too low

  3. #3
    Join Date
    Nov 2001
    Moose Jaw, Saskatchewan, Canada Occupation:Interprovincial Plumber, Commercial Gasfitter Interests:
    Use a tekmar mixing control with a injection pump. Go to for all the info and sample applications.
    I love my job, but paydays Thursday

  4. #4

    I went to the tekmar site, but I could not find what you were referencing. I did see a lot of snow melt systems and a lot of packaged boiler controllers. I also noticed that they have a 4-way valve.... What do you use that for?

  5. #5
    Join Date
    Aug 2002
    manitowoc wisconsin
    I agree with rick primary/secondary piping with injection is the way to go.Tekmar makes good stuff!Go to thier application drawing library.The controls have the capability for multiple zones including snow melting look deeper.

    [Edited by markwolf on 08-04-2004 at 11:53 PM]
    Take your time & do it right!

  6. #6
    Join Date
    Sep 2002
    It sounds like to me that adding the tekmar stuff is making complicated.

    I'm also confuse of why you dont think a thermostatic mixing valve wont lower the temps enough to your floor
    emitter even with high temp emitter.

    The three way "mixing valve" has a internal thermostatic element that will react to change of the incoming fulids
    by opening and closing its inlet port as necessary to
    maintain a nearly fixed outlet temp.This is why the circ
    need to be after the valve.

    One boiler,high and low temp emitter the tmv is just find for this type of setup..thats what they are made for.

    Primary/secodary piping is the way to go.If your floor emitter is the last thing on your loop,I see no problem
    why the tmv will not do the job.

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