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Snow melt slabs

I have a snow melt system in my driveway. 4 zones approx 500 sf per. Using heated glycol running through 3/4" pecks @ 9" on center. The boiler is capable of heating the glycol to over 100 deg but is there a temp that is better suited for this application as to not damage the concrete with thermal shock?? The slab is normally below freezing at the beginning of the cycle so the glycol will go into the slab at 80 or 90 deg and come back to the heat exchanger at below 30 deg for an hour or two


  • GroundUp
    GroundUp Member Posts: 1,926
    Lower the better, depends how fast you need it to melt. I've got a sidewalk system at home I've run from well below zero with 150 degree glycol about a dozen times now, trying to break it, and it hasn't failed yet after 4 or 5 years. Typically I run it about 100-110 because I'm impatient, but again lower is better if you can get away with it
  • Zman
    Zman Member Posts: 7,573
    edited January 2019
    What size boiler? At full fire, your delta t will be fixed. Unless you have a huge boiler or very low flows, you won't get that wide of a delta.
    You should be able to melt snow with a supply water temp of 100-120 degrees.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    HVACNUT Member Posts: 5,863
    Agree with above. But you need to be proactive and start the boiler before the first flake hits the ground.