grundfos isolation flange . . . i don't get how it seals

archibald tuttle

unlike most spinning flanges the o-ring doesn't hit on the non=spinning surface, the brass of the non spinning surface is kind of carved away on two sides. I spent years getting used to better rubber o-rings over the flat gaskets. i guess i have to go back and man it does not seem like much sealing surface even for the flat gasket but maybe its been rough and ready tested. anyone done any of these?

hot_rod

They don't always seal, depending on the type of gasket and circulator. Some circs have a large diameter square o-ring that misses the sealing area completely.
Pretty much need to use flat gaskets with those.
Not a great design IMO.

archibald tuttle

@Hotrod is there a smaller o-ring convention on some pumps. i'll probably eat these and wait until i find a circulator with the small convention. neither my standard grundfos nor taco rings hit the sealing area on these.

archibald tuttle

and what were they thinking with those notched away sections of the small brass portion of the flange face?

hot_rod

Those flats allow the steel flange to slip on the valve. It would be tricky to make the brass valve with the steel flange assembled So either that "drop connection" or a snap ring.

Solid_Fuel_Man

That's dumb!

Not a fan or spinning flanges anyway. Just put the flange in the correct orientation. All my suppliers carry pumps in either the standard orientation or reverse flange. No issues with pump flanges. 

Tha said I like the black Grundfos iron flanges, they are much heavier than any others. 

 Webstone for iso flanges has never let me down. 

I still like to use a ball valve and not the iso flanges, I can do an install more economically in most cases. 

JUGHNE

I just got a set of B&G iso flanges, 3/4" NPT...101221LF
Big smooth brass 2 3/8" round gasket flats, spud installed into ball valve so that steel flange can rotate.
Made in Italy.

B&G NBF-22 has grooves for square cut O ring.
Bolt spacing fits all the Grundfos pumps I have laying around.

Will see how these work out for a HW recir system to do over Christmas vacation with school out.....(no mask needed then).

TAG

I ordered them along with the new Alpha pumps -- I don't understand why they have the cuts either ....

All three pumps went on w/o issue --- mine had flat gaskets as well. Or the installers switched them out?

hot_rod

Still my favorite way to connect to a flanged circulator. These Burnley spun copper rotating flanges were invented by a plumber in Montana. Not sure if they are still around.
It allows you to use whatever valve you want, sweat, press, grip
Ball, gate, balance, purge, really an endless choice.

Often times you do not need two iso flanges if you connect to a header with one valve to isolate all circs on one side, for example.

Solid_Fuel_Man

Never seen those @hot_rod

I'm going to see if any of my local suppliers stock or can get them. Good for both open and closed system too! I've always used the Taco sweat brass for open systems if I dont need isolation flanges. 

archibald tuttle

@hot_rod and @Solid_Fuel_Man

interesting, I get where you are coming from on the convenience of that flange. its pipe size i assume. unfortunately google and ebay have nothing for burnley circulator flange. surprising that is has been so disappeared. i'll check with my sister in bozeman and see if this concern was ever heard of.

I do, though, like the double shutoff flange approach (so I'd be interested in more than one Burnley). Be into the circulator with no other piping involved.

brian