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UPONOR TruFlow valves

wmwinn Member Posts: 4
My hydronic system has been in use for 7 years.  Every season, I have sticky valves on zones that aren't used very much.  In every case, they are sticking in the closed position - resulting in a cold room.  Replacing these valves has helped, but it's just a matter of time before they stick again.

I was wondering if the installer made a mistake.  All of my manifold / valve assemblies are installed on the SUPPLY side.  It seems like the water pressure on the supply side would tend to keep the valve closed.  Shouldn't the valves be installed in the RETURN side - so that opening the valve would be aided by the water pressure?

Any help or advice would be appreciated!


  • JharrisSeattle
    JharrisSeattle Member Posts: 26

    Uponor truflow & truflow jr have valves on the supply and return side. Supply side is opened,closed and balanced using a alan wrench provided with the manifold. The return side has a adjustment cap that is replaced if acuators are used. proper orientation is as follows. Improper installation def. can affect performance.
  • wmwinn
    wmwinn Member Posts: 4
    Valves on supply or return?

    Thanks for the picture.... mine is a little different than this.  The supply side has thermostat controlled zone valves with a 4-wire MVA on top.  The return side does not have anything on it at all.  I believe the balancing is achieved by a black plastic disk on top of the valve - on the supply side.

    I'll take a picture and post, if that would be more helpful.  It seems to me that the supply side water pressure is keeping the valves closed.  If someone with more experience could confirm that my installation is backwards (Valves should be on return, not supply) - then it's worth calling another plumber to do the switch.

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