G union adapters gonna drive me crazy

archibald tuttle

different manufacurers use different standards for similar applications, e.g. 1/2 and 3/4 PRVs and backflow preventers. I need to buy some of the brass male nipple by female G union adapters that sometimes come with and sometimes not hte aforementioned PRVs and backflow preventers but it seems impossible or at least terra incognita to yours truly to specify the union end by size or even to say what the name of the fitting is i'm. looking for - nevermind that it takes an act of congress (maybe it will be easier in this session without getting back into the election) to even get the right washers to replace the originals which inevitably stick to the surfaces and fail.

forgetting my instinctive revulsion at these connections because they come from european habits, i do see that they work in certain circumstances but for an industry that has spent it's life designating sizes and naming fittings and is not so politically correct that it can still call them male and female, the inability to speak precisely about G-unions seems like a microaggresion to me :-).

takers, can anyone tell me what i'm looking for. in this case it is a TACO 3350 fill valve (outside of the g-union male threads is about 1.25) and, to add insult to injury, I can order them with the g-union adapter in press or sweat but not in IPS. I know IPS mean you needed an interal hex to install but that is how I set em up for years. i guess i'm being too burkian in resisting this change.

mattmia2

Are the taco and claeffi ones the same size? The washer is a terrible part of the design. I think I ended up cutting one out of a sheet of viton or fluoroelastomer to solve this problem.

hot_rod

The thread on the outside of a PRV, BFD, Fill valve, etc may not be a G nthread. Often they are a fine threads like this BFD.

Caleffi is switching all products to O ring connections, instead of fiber washers.

So the o-ring will be in either the tailpiece, or the valve body itself like this double check ASSE 1024 valve.

We do have some of the tailpieces with O rings in the catalog, it may or may not fit the nut on the valve you have.

I suspect that Taco has a large fine thread on the union side? A pic and measurement would tell what thread might be.

Screenshot 2024-11-08 at 3.10.12 PM.png

archibald tuttle

https://forum.heatinghelp.com/discussion/comment/1818857#Comment_1818857

maybe post the link here or did you PM. thanks. it does take an incredible amount of searching and I wouldn't think these would be so obscure. i may be wrong @hot_rod to refer to the taco connection as a G-union because I did once find a table of sizes for those and i'm not sure that these correspond but it uses the same kind of approach and flat fiber washer. i don't think i've ever had my hands on a TACO g-union pump. so will there be a rabbet in the union surface to hold the o-ring similar to the standard flange approach.

PC7060

https://forum.heatinghelp.com/discussion/comment/1818857#Comment_1818857

can you post here Mike?

hot_rod

Basically the US is the odd country out when it comes to flanged circulators and the use of NPT. That is why European manufacturers are so reluctant to make NPT components. Nobody else in the world want that thread. Maybe Canada ?

Although my latest batch of Viessmann stuff was 1/2, 1/2. The HP modules are NPT, the indirect tank coil and water connections, are BSP but adapters are included. The 20 G buffer is NPT. Both tanks were built in France.

I really wish we would merge to union body circulators, there is a much larger offering, they are a simple swap. No more rusty bolts, turn the motor to any orientation, iso valves are available also.

Maybe in a few years, is it 2026 or 2028 now?, when the PSC circs are no longer produced would be a good time to switch.

archibald tuttle

@MikeAmann thanks for the search indicia.

I did find the adapters i ordered last time i had this headache but they are female when what i want are the closer male version which (at least by the distributors i find) are not offered separately by TACO. Yet, according to pictures like this of their hydronic mixing valves, they do make the male adapters or have somebody make them so why are they so hard to find!

and the adapters are vaguely by application and not by size so i wouldn't even know if these actually fit a 3350 but i think i called joe mattielo when i had the trouble and he told me they did and a i bought some and they worked but then trying to search them up again is a massive PIA because there isn't really an industry standard as to what they are called or what would have appeared in the email confirmation of my order so i could just search my old orders.

that bugs me beyond measure. if its BSP fine, if its g-union fine or if its just some fractional or metric diameter with certain TPI, that's fine. just tell me what the hell it is. and the internal and external diameter of the required fiber washer!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

TACO is taking veterans day off so i can't call up my contacts there and **** about it at the moment. they usually all change their phone numbers once i start calling anyway :-).

is @John Barba still green? he changed his phone number , probably cause i pester him too much :-)

hot_rod

You almost need to pull the CAD design file to know what thread they cut. I don 't think measuring the diameter and pitch will tell much if it is an OEM thread. It may be in Master Spec or a BIM file.

That may be a re-badged valve and the file would be with the actual manufacturer.