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Uponor manifold incorrectly installed. Can I simply reverse the pieces?

I have a radiant heating system in my home, and I noticed my uponor manifold is installed incorrectly. I have attached a photo below. As you can see, the hot water is going into the return line of the manifold, and the cold water is coming out of the supply side.

Overall the system works, but Uponor said this isn't optimal. Also, the flow meters don't operate at all.

Can I simply swap the two manifold pieces in this situation? The water lines to/from the boiler are copper and can't be moved easily. The red loops don't have any slack in them so I can't move them. But I think I can just swap the placement of the two manifold pieces. Is this right?



  • a4agarwala4agarwal Posts: 7Member
  • IronmanIronman Posts: 5,084Member
    You should be able to. Which one is now the supply?
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • a4agarwala4agarwal Posts: 7Member
    Right now the one on top has the hot water going to it (you can see the red at the top right of the photo)
  • IronmanIronman Posts: 5,084Member
    Having the flow backwards will cause the flow meters not to work as you've discovered. Other than that, probably not an issue. You should have no problem switching them other than purging air which may be minimal if the manifold is higher than the tubing.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • VoyagerVoyager Posts: 214Member
    I see no issue swapping positions. Check the middle pex connection on top as it looks pretty misaligned in the fitting. I am surprised it doesn’t leak.
  • GroundUpGroundUp Posts: 541Member
    The very first radiant system I ever installed was my own back when I was 18 in my 40x40 shop. Used Zurn manifolds, piped it backwards just like yours. It's been that way for 12 years and has never failed to heat the building (in MN, was -35F this morning) with 100 degree supply water. No, the flowmeters don't work but I'm okay with that. Judging by the delta T and pump curve, it's flowing perfectly
  • DZoroDZoro Posts: 768Member
    I haven't used those manifolds so I could be wrong on this, but it looks like you can remove, and just swap out the flow meters with the flow valves. It looks like the actual manifold of the supply and return are identical.
  • hot_rodhot_rod Posts: 11,609Member
    If ever actuators were added, they do not like to work against reverse flow. I'd change it if you can.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • a4agarwala4agarwal Posts: 7Member
    I contacted Uponor and they said that while most of their manifolds would work fine if reversed, this one (the plastic version) might restrict flow in this direction. So they recommend swapping the pieces.

    Thanks everyone for the help on this.
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