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.

Dedicated manifolds for panels, underfloor and slabs

HotRod: Thanks for your reply yesterday concerning keeping each manifold for one temperature. I drew out a plan for the 10 panel radiators currently being planned on, and the 3 slab zones. Here is what I came up with for the radiators; If I split the panel radiators into 2 banks, and ran them in series, the total loop length would be about 300'. If I did all home runs to the boiler room, tubing would total 900'. If I placed (2) Caleffi manifolds near the loads, the total tubing would be 675'. It is hard to get all the tubing to the boiler room, so the remote manifolds are my choice.

Since there will likely be additional panels, I'd order manifolds with room to expand in the future.

One question: Would it matter if the Grundfos Alpha 2 was in the boiler room, right off the supply manifold, or remote located at the Caleffi manifold? My thought is to put a 1" ZV on the return line in the boiler room, the Alpha 2 directly above it on the 1" supply, run 1" HePex to the Caleffis, and then home run each panel to the Caleffis. All units on thermostats, tied into boiler room.

Does that make sense?

Thanks to everyone who comments.


  • RetrosPex
    RetrosPex Member Posts: 56
    Hotrod: Could you comment on this earlier post of mine? I ordered, and have received a beautiful Caleffi 8 zone 1.25" inverted manifold.

    Grundfos Alpha 2 pumps here now too, along with panel radiators. I need to make decisions on buying Twist Flows for individual zones, or putting a 1" Caleffi ZV at the 2" copper return manifold off 80g Boiler Buddy. I plan to home run each radiator tot he Caleffit. Then I will buy more of them and start in on the underfloor, and in slab.