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Connect PAP to CI radiator- best way?

Bry_2Bry_2 Member Posts: 14
I want to add a small cast rad to my PAP fed system on a separate branch off my manifold. How is the best way to connect my PAP pipe to the spud on the rad? Thanks.


  • JohnNYJohnNY Member Posts: 2,135
    Radiators don't have a spud. What's a PAP? Is it Pex-Al-Pex? If so, you'll need a crimping tool and a crimp ring or else use a mechanical fitting sold by the distributor of the tubing you've bought.
    For installations, troubleshooting, and private consulting services, find John "JohnNY" Cataneo here at :
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  • Big Ed_4Big Ed_4 Member Posts: 1,095
    Cast Radiator with Pex , scares me with all that weight and nothing holding it to the wall .. Send an lag bolt into the wall to square ..

    Look into steel panel radiators , The new radiators , they are made to use Pex , and they use brackets to hang on the wall
    I have enough experience to know , that I dont know it all
  • Bry_2Bry_2 Member Posts: 14
    edited September 2017
    Thanks for the info. PAP is yes pex al pex. I just want to use an existing small cast rad to heat a small room that is electric only. I figure my manifold has an open valve and I have all this pex al pex leftover but I just don't know how to transition the pipe and 1/2 inch adapter to the 1 1/4" outlet (spud I think) to the PAP adapter. It's a small rad but I plan on securing it to the wall so nobody gets hurt.
  • Danny ScullyDanny Scully Member Posts: 1,038
    Spuds are from hand valves or radiator elbows. Do you have an old spud from one of those screwed into the radiator? You'll need to remove that to get to the female threads.
  • Bry_2Bry_2 Member Posts: 14
    edited September 2017
    All i have exposed at the rad are the union ring outside and what looks like half the union fitting inside and I am looking to tie into that with my pex al pex supply and return. I think it is the spud thatnis exposed, the part that connects to the old valve. Can I get a fitting to connect to this or do I need to source the valve?
  • Danny ScullyDanny Scully Member Posts: 1,038
    You can't do either @Bry. You need to remove the spud. At that point you can get the appropriate adaptor.
  • Bry_2Bry_2 Member Posts: 14
    Thanks.. I'll borrow a spud wrench and go from there. Is there usually a spud on both in and out connections?
  • Danny ScullyDanny Scully Member Posts: 1,038
    Yes, however, in my experience they almost always break. Usually have to cut/chisel it out or cut the collar off and wrench the whole thing out.
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