B & G Dou - Flo Valve??? Main loop Supply/ Return and Secondary loop Supply / Return

BarthBoiler

My question is what can I use in replacement of this valve and how to pipe it .. I'm sure I'm over thinking it as well … I have called B & G / Xylem spoke with local reps and no-one knows what it is or what it does … There is 4 zones all have their own valve identical to this one Main supply goes into this and out to the main return loop while in the center of this is the units zone loop supply/return. The red Bell looking things are the valves , now i dont know if they are for balancing or are for isolation. or both. my problem is this unit is getting hottttt!! replaced the thermostat it is functioning properly. The pump is with-in a year old. I even pulled the circ check valve to make sure it was working properly. so the only thing i could think that's faulty is this B & G valve. Please any assistance would be great. Im sure ill be replacing all of them sooner than later there is 8 zones per floor 14 floors .

20250206_101425.jpg

20250206_101429.jpg

20250206_101439.jpg

delcrossv

It's a mixer for primary secondary piping. See Idronics 7 for more details. Paging @hot_rod as Caleffi probably has a replacement.

bburd

The manufacturer didn't know what it is… but Heating Help did! The site is such a wonderful resource!

BarthBoiler

Thank you Delcrossy so much! I should have came here first honestly. You guys are truly awesome much appreciated. Now the question is. If this mixing valve is faulty could that be the reason this zone gets hot when the t stat is not calling and the circ is off? Nothing else is tied and they have in-floor. I stuck with the original style 120v heat only w/ anticipator New now after all the troubles and still troubles..

hot_rod

https://forum.heatinghelp.com/discussion/comment/1845085#Comment_1845085

I can’t quite see the date at the bottom of that page?

delcrossv

https://forum.heatinghelp.com/discussion/comment/1845117#Comment_1845117

I think it's 1965.

EBEBRATT-Ed

@delcrossv Good catch never seen one of those.

delcrossv

https://forum.heatinghelp.com/discussion/comment/1845103#Comment_1845103

I'd think so if the secondary has low resistance. I've never put one in,so it's a guess.

hot_rod

I searched 700 of the 2500 legacy product docs at the B&G site and didn't come up with that spec sheet.

I would think someone at B&G could find that info, maybe contact the Little Red Schoolhouse, their training center.

It looks like more than just a set of close tees, it has some adjustability by the looks of it.

BarthBoiler

I searched 700 of the 2500 legacy product docs at the B&G site and didn't come up with that spec sheet.

I would think someone at B&G could find that info, maybe contact the Little Red Schoolhouse, their training center.

It looks like more than just a set of close tees, it has some adjustability by the looks of it.

Thanks for taking your time @hot_rod I truly appreciate it This item seems to be a recluse, I will try to reach out to the little red school house and see what they can come up with. I had a chance a few years ago to get a glance at damaged unit on a shelf, and i did notice it seemed like there was a flap like a check valve that had threads going into the flap assuming for the valve handle to control the flow… i couldn't see the other side because it was not removed at the time . Im going to assume again the opposite side of the valve was the same… At this point I am curious as the exacts on this valve and also I need a replacement that will work for the customer. I found this item Series 521 MixCal™, Adjustable thermostatic mixing valve with gauge (NPT). Hoping this would work as a replacement, but Also don't want to jump the gun and do the customer a disservice .

Thank you everyone for the input I'd buy coffee and doughnuts if I could :)

BarthBoiler

Also B & G wasn't much help in the matter, I was directed to my local reps… who actually laughed at me