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.

How to setup a radiant heating system with 2 manifolds

freq Member Posts: 1
I'm designing a radiant heating system for the home I'm building. It's 3000 square feet total slab on grade. I'm trying to keep the pex tubing lengths between 250 and 350 feet. The majority of the circuits will come from a manifold in the utility room. Unfortunately, this room is too far from the garage to run circuits there. I'm thinking I'll need to put a manifold in the garage to run circuits in the garage. My question is, how do I feed hot water and return water from the manifold in the garage? Would I need a second hot water heater?


  • Zman
    Zman Member Posts: 7,355
    There is no reason you could not install a remote manifold with larger supply and return lines going back to the boiler.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Oliveone
    Oliveone Member Posts: 7
    Did you do a heat load for the house and the garage? You should keep ½ pex under 300 feet per loop. How many square feet in the garage, how tall, insulation level and how fare from boiler to manifold? Need to know how many loops and GPM is need for the garage to come up with pipe size to the manifold. In short lots of variables!!!

    Heat load design will give you most of the info you need. When I put my pex in the floor in 2015 Uponor provide me with the info for the pex placement. 4 loops at all just under 300 feet each.

    Keep us posted.

  • GroundUp
    GroundUp Member Posts: 1,422
    Essentially it's just a matter of cutting two tees into the same system you'd have if it were all a single manifold, and using either another pump or a pair of zone valves (one for each manifold) to make it a 2 zone system. Then as others said, you'd run pipe between the boiler system and the garage to connect the remote manifolds.
  • Zman
    Zman Member Posts: 7,355
    The OP is "One Hit Wonder" from 10 weeks ago....
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein