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Isolation flanges

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  • archibald tuttle
    archibald tuttle Member Posts: 819
    edited November 2020
    just trying to make my shortest post ever and then commenting. but i am kind of interested in everything. manufacturer. quality/servicability of ball vall and stem. material of flange (see some, e.g. grundfos and maybe taco, that flanges seem to be different metal from the brass valve body but i can't really tell). gaskets, flat vs. ring, availability of press versions although i'm still sweating and threading many.

    I need to pick some up and i'm not absolutely opposed to offbrand chinese vs. branded chinese or made . . . american , german, swedish, who knows where these are made. Pricing (without mentioning specific numbers) can be found in a competitive range so it seems like I don't have to pay twice as much for a brand name but sometimes generics have good features and quality so I'm really interested in wide ranging discussion, especially since i'm not going to be able to flit booth to booth and see who can give me the best speil at AHR. Paging @hot_rod
  • hot_rod
    hot_rod Member Posts: 15,070
    In my experience with valves both inexpensive and most expensive is that all valves can seize after time. It has to do with fluid quality and how often they are exercised.
    Regardless of the name on the handle, most valves these days are imports. I've never seen an Uber engineered iso valve, really little market for them. Iso valves mainly are used when a circ fails. Nowadays that could be 20 years down the road.

    I prefer valves that at least have a stem packing nut that can be tightened, that is the most common leak path. Some brands leak around the stem as soon as they are installed, probably due to the assembly machine and tolerances.

    I prefer Italian brass, but as you know...
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Leon82
    Leon82 Member Posts: 684
    I have Tacos. I believe the flange will swivel so you can orientate it how you need it.
  • archibald tuttle
    archibald tuttle Member Posts: 819
    edited November 2020
    @Leon82 the swivels are handy and it emphasizes that the real sealing is done at the center of the flange where it doesn't spin whether with ring style or flat seal.

    do you have the newer tacos. their shut off flanges say brass for material, but I don't know if the spinning part of the flange is brass because its painted green and I can't really get a look at the thickness profile from the side. the grundfos ones are definitely a different material on the spinning flange vs. the valve body - stainless? - and I'm looking at the pictures and maybe there is some kind of dielectric o-ring or something. brass and stainless aren't that far apart on the galvanic scale so threading brass into a stainless heat exchanger, for instance, is probably better than cast iron if wanting a threaded nipple and not adapter format right to copper (which is about the same distance anyway as brass) but they do make stainless nipples so i even wonder about approaches that mix brass and stainless. and, in the era of no lead brass (what the hell for when it comes to heating flanges and pumps?!) the premiums between brass and stainless are similar and maybe even have flipped a little although I haven't run into a completely stainless isolation valve.

    indeed the conservation of the more expensive but less corrosive material means pumps (and maybe zone valves) might eventually migrate to G style unions. certainly the cheapest way to buy stainless pumps.

    and then there is the question whether its not bad to have a little sacrificial iron somewhere in there that takes the brunt of the problem although it seems like (speaking of G unions) maybe they could make some sacrificial link between two brass or stainless threaded G unions with some kind of monitor for when the tubing fills up with rust and then you could throw it away and thread another one in (kind of like what we used to do with the cast iron quick fills . . . )

    no question in my mind that the brass isolation flanges are miles ahead of the nonisolation steel flanges that were the bedrock of the industry for 50 [100?] years. and yet the steel flanges, when not in leaking or sweating applications were goood for 50 [100?] years . . . so a lot of this is just my typical overthinking.

    maybe ditto for pump material with cast iron 007s and bosses just fine 25 years down the pike, although critical pumps or questionable water quality i'm always going to go solid brass or stainless these days.

    and "I think maybe they say you can change the flange on the grundfos model isolation flanges, which i suppose could be handy if they have offerings for the odd pump that needs a different one although I have never run into that situation.

    @hot_rod I totally agree re the packing nut. I put a bunch of watts isolation flanges in early in the isolation flange revolution when I repiped the system in my own house and watts was a good name stocked by a local distribution house i rely on and i didn't think about going over the engineerings of the flanges.

    no 'packing nut' on these. I don't know if they have changed design but these leaked almost immediately. not continuously, thank god for small favors. cause i used threaded on the boiler side and solder style to the 3/4" loop piping. big PIA to change those.

    and have to agree, going to ball valves seems like valhalla compared to the system I was working on yesterday with 2" gate valves that seem to take a half hour to close, but the systems I have with 2" ball valves I'm not entirely confident that I continue to get reliable absolute shutoff, junk carried into the seats, etc. and they do seize if not exercised. Which then gets me into the conundrum, do I want to exercise as many as I can all the time but one of them is going to get compromised in the process. then there is that belts and suspenders instinct to put in a valve so you can change the valve . . .

    ok, so if that is overdone and only multiplies the exercise problem, then I wonder about pressing them on vs. threaded, because a brass valve on a copper adapter I am going to be able to change. so then the question is, is the offset standard or am i going to have to redo the piping anyway because a new isolation flange is longer (or shorter) than the old one.

    and then i realize that i could have repiped a couple in the time i spent thinking about this. but, if i'm going to obsess anyway, i'm just trying to get as close to right as I can . . .

    SuperTech
  • hot_rod
    hot_rod Member Posts: 15,070
    I expect within the next few years most small circs will be composite bodies, so no need to worry about electrolysis at that connection.
    I'm not sure valves will switch to composite or polymers soon? Certainly PVC and CPVC and other plastics have been used for valves for a long time.
    I disassembled a 15 year old Maxi/ Laars comb boiler recently, it had a composite volute Grundfos, ported out to connect to a manifold inside. Even had a Caleffi air vent built into the volute:)

    A few reasons for polymers, less concerns with corrosion and easy to manufacture, less weight. Once they drop out of the mold they are pretty much ready to assemble, holes, threads, mounting pins are all part of the mold. Cost of the raw material is a bit more stable compared to copper alloys, brass for example.

    I agree with union body circulators, simple to install, same gasket fits all brands of pumps, rarely leak at the gaskets. 2 bolt flange style need to disappear!
    i doubt you will ever find a perfect, never fail ball valve, certainly not for the $$ you are willing to spend.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • GroundUp
    GroundUp Member Posts: 1,283
    I don't think Webstone can be beat in that department, honestly. I buy probably 120-150 pairs of flanges a year and have tried literally everything available in the US either online or local, and keep coming back to Webstone. They have an adjustable packing and most come with T handles in addition to long handles for maximum flexibility especially when coupled with rotating flanges, although I would rather have the non-rotators if possible. Wright Valves makes a darn nice iso flange as well, at a great price compared to Webstone, however the only supplier I can find that carries them has been perpetually screwing up my orders, overcharging, sending damaged parts, sending nothing, etc and then denying fault- to the point that I went from spending over $100k a year there to boycotting them completely.