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Boiler replacement radiant heat in garage

WirenutWirenut Member Posts: 6
Preferred replacement boiler choice for garage with radiant floor running glycol, load 46,000 BTUH design T 122 F, no other load. Also brand of glycol preferred


  • GroundUpGroundUp Member Posts: 991
    Where did the 122F come from? Seems mighty high for a garage. I'm really liking the HTP UFT-80W for jobs like this, and any inhibited propylene glycol will do the trick but I use either Cryo-Tek or PlumbGuard typically. They've both done me very well. How big is the garage and what's the tube spacing and diameter? All one zone?
  • Solid_Fuel_ManSolid_Fuel_Man Member Posts: 1,978
    I keep a detached radiant shop 60F with 100 degree water when its below zero. Two 10x14 foot overhead doors, 2500 square feet.

    Tubing (done by someone else 20 years ago) is 1/2" 12"OC. There was a chimney and oil boiler where that manifolds are. We demoed it all.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • WirenutWirenut Member Posts: 6
    122 degree supply T came from heat loss by uponor dist
  • hot_rodhot_rod Member Posts: 13,500
    If it has a wide tube spacing that temperature may be required to meet the load.

    Use a good brand glycol, for the best inhibitor protection. DowFrost, Rhomar, Nobel, Hercules are a few. 35- 40% should be adequate.

    Buy the pre-mix so you do not destroy the fluid with hard or high TDS job site water. It really should blend with DI or RO water.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
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