Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Boiler replacement radiant heat in garage

Wirenut Member Posts: 9
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


  • GroundUp
    GroundUp Member Posts: 1,868
    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_Man
    Solid_Fuel_Man Member Posts: 2,646
    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!
  • Wirenut
    Wirenut Member Posts: 9
    122 degree supply T came from heat loss by uponor dist
  • hot_rod
    hot_rod Member Posts: 21,898
    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
    Living the hydronic dream