union standard for TACO pressure reducing valves

archibald tuttle

just got a TACO 3350 out of the box and notice that they no longer (at least in the packing a bought) include a union fitting for the inlet.



i guess they figure with a union on the backflow preventer and with the cartridge style serviceable nature and brass bodies of these german valves that there will be less need for a union at the pressure reducing valve.



color me old fashioned.  i'l like to throw in the union because i have a tee between the pressure reducer and  the backflow preventer upstream of it with a ball valve for my quick filling.  I;ve never been satisfied with any 'quick fill' adaption on these various valves. Reading the literature on the 3350, everything sounds good, like you can trigger quick fill with a button push, and engineers tell me they get pretty good flow, but only up the set pressure according to the literature that came with it. 



So TACO tells me this is a standard 3/4" ISO union. Apparently the bits i've save over time are actually 1" iso x 1/2" sweat of course.   So trying to search for the 3/4" and you get brass to brass tapered seat unions coming up as well. Google can't parse the difference well, unless there is a way to be more specific on the search.  These are take a flat faced rubber or fibre washer face seal type union. the literature gives the threads (1 and 1/4 x 14) but not any designation that i can easily search.



i have found a few scattershot but they are frighteningly expensive - at least those i've found - and they don't even have any specs online that truly indicate to me that the thread sizing matches.



If anyone knows what i am looking for and where to find it at a rational price, that would be great.  my plumbing house locally just look at me and say, if you buy so and so's pressure reducer it comes in the box.  So much for all the help you get from the local counter that is supposed to make you want to keep them afloat. I'm not complaining if they didn't have it in stock.  i would have been willing to have them get it for me if they wanted to go to the trouble of finding, which you'd think wouldn't be too hard for them. but i'm on my own on this one, except for my thousands of Heating Help BFF.



brian

SWEI

If these are a "Nut G" type union

actually expressed in inches (which oddly is an EU standard) you can get copper adapters (female thread, fits the male valve body) from Mr. PEX.

archibald tuttle

Mr who . . . or is the Dr. pex

Mr. pex seems to be system manufacturer and didn't have an easy product by product interface from their front page. i see mr. pex products at pex supply but can't bring that union.



What the heck does Nut G stand for?



google searches bring a few hits but no reliable listings or any specs. i do see that a few of the pressure reducing products are listing "less union" on pex supply. so i can find instances of not selling them but can't find anybody who is selling them, at least that i am sure it is them.



zorotools of all odd places has a pair for sale that are 1/2" copper and i believe they came up when i searched 3/4" union but i don't see specs. The pair is $24.00 which seems a little rich but my main problem is terminology, specs, knowing i'm getting the right thing and that i can compare a few sources to see the most cost effective.



TACO didn't mention Nut G, they said 3/4 ISO, and their spec says 1 and 1/4-14 UNS-2A. it does seem you are on the right track with the Nut G reference although most things (including some ball valves) offered with Nut G union have no pictures on their ecommerce pages. further complicating my hope of knowing what the heck i actually want.



thanks for your help.  it's more so far than i've gotten anywhere else.



brian

SWEI

Nut G

is what Aquatherm calls their adapters.  I've never been able to Google my way into a domestic source for them, but I'm pretty sure they're the same fittings used on most EU solar and boiler circulators.



Turns out that Mr. PEX only stocks them in 1", 1-1/4", and 1-1/2" union sizes (each of which mates with the next size down in CTS.)



I'm pretty sure these are the same fittings Caleffi uses -- check out P.68 of their 2013 catalog.

archibald tuttle

can't find right catalog

SWEI



i keep finding 36 page catalogs. i found something called a catalogue and something call a fittings and accessories catalogue but they both have only 36 pages so i can't find page 63.



this is the link i'm using, do you have a different one?



http://www.mrpexsystems.com/professional_downloads.asp



thanks,



brian



PS -there should be a fairly good size pile of these unions somewhere from all the folks who got on in a box but were replacing a valve where a union was already installed. now that i am missing one, i am looking at every installation i service which is plenty on account of the cold and freezing pipes.  hyrdronic's achilles heal.  anyway, i now see but don't know why i didn't remember that virtually all the backflow preventers seem to have what must be the 1" nut G style union and all the pressure reducing valves (at least the residential sized ones) have the 3/4" nut G style.   I'm not sure why they wouldn't have standardized between these but **** do i know.  And why these remain mysterious european knowledge is beyond me since they are in probably half the homes in america. talk about the manchurian heating system.

SWEI

Union transition fittings

Page 20 of http://www.mrpexsystems.com/pdf/MRPEX_Catalog_2013_NoPricing.pdf under

Sweat Transition for 3-Way and 4-Way Brass Mixing Valves

archibald tuttle

just my luck, only 1 G and up as you said

but at least i actually found one in America.  unfortunately they carefully list the pipe side size as 1/2" sweat but do not list the union size.  talk about frustrating. because of course both the 1G and 3/4G are often used in 1/2" sweat, one for backflow preventers and the other for pressure reducers, so i have no idea what size these are.



http://www.zorotools.com/g/00054945/k-G1550656?utm_source=google_shopping&utm_medium=cpc&utm_campaign=Google_Shopping_Feed&kw={keyword}&gclid=CL-NmaCv7LsCFcU5QgodvSwAjg



zoro tools is an interesting mix of stuff often at decent prices.  kind of like a cut rate online version of graingers.  they often are fairly good in their documentation but not in this case.



so if i knew what pumps they were servicing with these and what standard was most frequently applied in that context, i would know if they were the right size. they do seem to intended for "hot water return pumps" -- i assume maybe that is hot water recirculating pumps for keeping hot water close to outlying taps.



if they happend to be the right size,  $12 a piece seems kinda steep, but as compared to unavailable . . . 



I don't understand why the companies that make these valves don't offer this as a part and while i can understand that it improves economy on replacements to sell them without the union, they ought to include a new washer at least.



my humble opinion as usual.



thanks for helping me look.



brian