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help identifying manifold and flow meters

See pics.

Helping a friend trouble-shoot a ~15+ year old radiant system at a co-op house. The manifold does not have any valves on the return side, just the pex compression fittings and smooth on top, with flow meters on the supply manifold. I can't make out any brand name on the manifold except an indiscernible stamp in the cast brass which might be a few letters. The flow meters have what looks like a lower case tn?

The main question we're trying to answer is that he is convinced the supply and returns manifolds were installed in reverse (improperly), and that's why none of the flow meters are working. We have one spare flow meter and it does look like the spring compresses up for increased flow, which would make sense if water is entering from below, not spring extends down for flow entering above, like what i'm used to seeing. So his argument makes sense, but I said I've only ever seen flow meters designed to work on the return side. It's entirely probable that it was installed improperly as the system was installed with some mix of non-professional labor originally.

So question 1,
Are there some flow meters which work on the return, and i am mistaken with that assumption that flow meters are always supply side only?

2, what brand is this so we can buy replacements for the flow meters?

And I guess also 3, if all the flow meters are bad, is that indicative of some other deeper problem?


  • Derheatmeister
    Derheatmeister Member Posts: 1,542
    Looks very similar to Roth..
    Can you not just repipe/reverse the flow in the mechanical room?
    If the repipe in the mech room does not work you could just swap them...However that may open a can of worms since these look dated and O-rings may be compromised during this operation..
    These O-rings may be metric and hard to find..
    It may be time for new manifolds.
  • EternalNoob
    EternalNoob Member Posts: 42
    I can re-plumb supply to return in the mech room pretty easily. Just don't want to do that if it's not actually plumbed improperly, though i suppose it may be the thing i'll have to do to answer that question.

    Ah, i found a Roth brochure on the google that shows a flat valve-less manifold. That looks pretty close. Thankyou. Same brochure shows flow meters on the *supply* manifold.