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Disconected Uponor zone valve - a couple questions please

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MoreCowbell
MoreCowbell Member Posts: 16
edited April 27 in Radiant Heating
4-valve Train.jpg
Upanor valve for kitchen.jpg
Disconnected top of kitchen valve.jpg

Hello,

This is something I discovered in a new house I just bought. One zone valve (Uponor) in a series is disconnected. The “base” has what looks like a little pin sticking up. Therefore, in looking at the “cap” (top part), I would think I’d see a corresponding “pocket” that the pin inserts to. But as shown in the picture I took, there is no pocket. On inspection, neither the pin or the blue/green mating “dot” retract. And the top part does not want to thread onto the brass bottom part. Very strange …

Does anyone recognize this Uponor valve? Can anyone explain why it won’t reconnect?

Any help in explaining this mystery is appreciated.

Comments

  • hot_rod
    hot_rod Member Posts: 27,705

    When the pin is up, the valve is open. Typically there is a plastic cap that replaces an actuator. This allows you to manually operate that port. Screwing down the cap closes the port.

    Sometimes those pins stick and that is what destroys the actuators. You should be able to push the pin down with a piece of wood, etc.

    Uponor has used a variety of different manifolds and actuators, I don't believe they make their own. Some versions used the Honeywell PowerTrack, a rack and pinion actuator. Those are hard to find, but a conversion kit is available for some.

    Send a pic.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • MoreCowbell
    MoreCowbell Member Posts: 16

    Thank you HotRod - I forgot to attach the pics !! Please see them now.

  • GGross
    GGross Member Posts: 1,940

    Whoever replaced the actuator didnt get the right adapter ring and just left it like that lol

    you need to add this spacer ring to that one

    https://www.supplyhouse.com/Uponor-Wirsbo-A3019900-Spacer-Ring-VA33-for-Thermal-Actuators?srsltid=AfmBOoqfYG-shqITacv0gv_S2uCyTY4KWzkfLh5VTkc2Spa999zJk1SV

    Bernie_the_Brewer
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,769
    edited April 28
    https://forum.heatinghelp.com/discussion/comment/1895209#Comment_1895209

    Those adapters were for the old Wirsbo manifolds, no? The manifolds are marked "TA" - Tour Andersson. This looks like a newer (Uponor) manifold.

    Edit: OK - I see the Wirsbo name now.

    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • MoreCowbell
    MoreCowbell Member Posts: 16

    Thank you GGross & Alan.

    Per Bob’s comment, I inspected and see that that pin can be depressed ~⅛”. So as it was found, it appears that the valve has been “stuck” open for who knows how long.

    Especially when I couldn’t readily thread on the top piece, it struck me that the base and top piece may be incompatible. GGross’ link to that missing “bushing” was appreciated; I’ll explore that.

    Amazon wants $25 for the same ring !! 😱

    https://www.amazon.sg/Spacer-Ring-VA33-Thermal-Actuators/dp/B06XNMWS1V

  • MoreCowbell
    MoreCowbell Member Posts: 16
    edited April 29

    A little more here:

    Per Google AI for the actuator:

    The Uponor AEF 40405-00 (also known as part number A3023522) is a 24V, 4-wire normally closed (NC) thermal actuator designed for radiant manifold zone control. It consumes low power (1W), includes an end switch to activate pumps or relays, and is compatible with Uponor EP, Stainless-steel, and TruFLOW manifolds.

    This is the opposite of what Hot-Rod suggested above, and in fact makes more sense: that the loaded pin against the spring would open the valve, and that the relaxed position would be closed. So – for whatever reason the actuator was disconnected - the valve has been closed. I take the advice to get that ring to see if that will facilitate reconnecting the actuator.

  • hot_rod
    hot_rod Member Posts: 27,705

    The valve was closed with pin up, that’s odd.

    If there was no flow in that loop, could be the pier on the other manifold is closed. That would prevent flow with the actuator removed.

    Got a pic of the other manifold?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • MoreCowbell
    MoreCowbell Member Posts: 16

    Hi Bob & thanks. I was only reporting what I read on Google, which (as I said) suggested that when the pin is up ("relaxed" state), the valve is closed. Since this (4-zone) train was unfortunately not diccovered during inspecton, that Kitchen loop could not be tested per se. Which other manifold were you referring to?

    Not sure of the term "pier".

  • hot_rod
    hot_rod Member Posts: 27,705

    You have a supply and return manifold. Actuator typically on return manifold.

    On most manifolds you can turn flow off on the supply or return manifold. Generally the flow meter on the supply manifold acts as a shutoff. (valve #1 on the lower pic)

    I have not seen a manifold that closes a port when the pin is up? If so it would take a different type of reverse motion actuator. When you screw on the actuator it pushes the pin down, closed. The actuator heats up and allows the pin to move up.

    If the pin is up, actuator removed, and you have no flow, (valve #5) it could be the opposite manifold port is turned off.

    Or the pump is not running.

    This Caleffi cutaway shows the pin motion and the actuator vs flowsetter manifold.

    Screenshot 2026-04-29 at 2.04.18 PM.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • MoreCowbell
    MoreCowbell Member Posts: 16

    I appreciate your post Hotrod, and the description for the actuator shown seems to be very much like mine that was disconnected. The system of a supply & return manifold is foreign to me and definitely now what I have. My understanding has always been that the boiler sends hot water out to one or more manifolds and attached Aquastats open depending on respective T-stat state.

    In my case, there are 2 Wirsbo manifolds: one with 6 Aquastats attached and the other with 4 Aquastats attached. Interestingly, a few zones are served by 2 Aquastats. As I said, when I can, I aim to get that “missing ring” that will allow me to reconnect the actuator.

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