A valve solution, looking for a problem

hot_rod

This doesn't make any sense to me? What conditions could be presented in a primary secondary piping that would warrant the need for a PAB in the boiler secondary loop?

Did engineering and marketing consult on this

Tinman

Remember the illustration Dan had in one of his books where it showed a semi-trailer truck slamming on the brakes inside a length of pipe?

Maybe that?

SuperJ

There is a bridge between the tee's allowing the flow to go around the pressure bypass, I don't see how you could develop enough pressure to put any flow thru the pressure bypass unless the pipe was seriously oversized.
In fact any one of the 4 circulators in the graphic could run on it's own without deadheading or creating any unwanted differential pressure. Everything is decoupled with bridges (sets of tees).

Alan (California Radiant) Forbes

It's like the peanut farmers providing recipes with peanuts in the ingredients. Panang beef with peanut butter, peanut butter and jelly sandwiches, salads with peanuts sprinkled on top, squirrel food with peanuts, etc. Those marketing exec's. are smart, but have us scratching our heads.

STEVEusaPA

I got this email today about the valve. Looks like their idea of a circuit setter.

Ironman

I'm a little confused by the installation instructions: they say to install the valve AFTER the circulator, but the diagram shows it BEFORE the circ.

Gordy

with delta P pumps. Why?

hot_rod

What would, or could change in the boiler flow path to require bypass?

No indication how to set cracking or threshold point of the valve? Wide open, or fully cranked down, somewhere in the middle? It is an adjustable valve that needs to be "set".

If anything it would be better applied on the zone circs if ZV were intalled.

Gordy

Depends on the boiler type, but in the present days of high efficiency it shoots it all to hell. I see the boiler hitting high limit with low load zones calling on top of an issue that’s already concerning.

hot_rod

Gordy said:

Depends on the boiler type, but in the present days of high efficiency it shoots it all to hell. I see the boiler hitting high limit with low load zones calling on top of an issue that’s already concerning.

The point of connecting a boiler as a secondary to a primary/ secondary piping is to assure it always has full flow, regardless or what any other pumps are doing. From my experience, when properly piped, it does do that. So what boiler, under what condition would need a bypass? A PAB is basically an adjustable pressure relief valve, a disc and spring pretty much.

I think putting stuff like this out there without explaining the purpose or intent, just adds confusion to the industry.

Bob518_802

By reading this, as a newbie just trying to learn what I can as I move forward with my project life... it sounds like mission accomplished on adding confusion, due to not providing explanation of the how and why of the device. But since I am new... to having to look at previous installations at my property, when I try to research many products, I often don’t find much information, but most professionals that use them often, just get what they need and move on. I especially find this with electrical items, but it is not limited to that industry.

Ironman

The main thing that they seem to be promoting this valve for is velocity noise from over-pumping a zone. OK, I get that and there may be a need for that to some extent where proper design was not incorporated into an installation. However, the confusion that I'm seeing is trying to promote it as something necessary for a boiler and leading some to think it belongs on a mod/con from their drawing and instructions. That's an idea that in my understanding is patently false and detrimental to a mod/con where the coolest return is desirable.

HVACNUT

If zones 1 and 2 were using zone valves rather than pumps, would it then be a feasible design?
And I dont get the primary pump pumping into the zone pumps.That wont cause pressure fluctuations?
I'm no piping guru by any means. Is it piped in series where if both zones were running, zone 1 would get the highest BTU output? Then zone 2 gets less BTU's, and so on? Would that have an effect on return temps and hence the bypass?
I'm going back to bed.

Gordy

hot_rod said:

Gordy said:

Depends on the boiler type, but in the present days of high efficiency it shoots it all to hell. I see the boiler hitting high limit with low load zones calling on top of an issue that’s already concerning.

The point of connecting a boiler as a secondary to a primary/ secondary piping is to assure it always has full flow, regardless or what any other pumps are doing. From my experience, when properly piped, it does do that. So what boiler, under what condition would need a bypass? A PAB is basically an adjustable pressure relief valve, a disc and spring pretty much.

I think putting stuff like this out there without explaining the purpose or intent, just adds confusion to the industry.

I should have been a bit clearer I was referring to mod/cons. As Ironman points out it’s not getting the coolest return possible.

Gordy

HVACNUT said:

If zones 1 and 2 were using zone valves rather than pumps, would it then be a feasible design?

And I dont get the primary pump pumping into the zone pumps.That wont cause pressure fluctuations?

I'm no piping guru by any means. Is it piped in series where if both zones were running, zone 1 would get the highest BTU output? Then zone 2 gets less BTU's, and so on? Would that have an effect on return temps and hence the bypass?

I'm going back to bed.

The boiler, and zones are secondary loops off of the primary loop.

clammy

If you can’t sell them where there suppose to go and there attended use then maybe you can sell them for something else for those who don t know .i remember ordering D b valves like 20 years ago and they where like what for what why then about 5 years ago the same guy tell me about how I should be buy these and how good they are I just smiled .most will just throw a ball valve instead if I need a set by pass in a $ tight job I’ll use a globe but they are less common these days in supply houses .with the vfd pumps these will go to even further into history .i will admit I rarely if ever see differential by pass valves installed by anyone.ain t that sad I know I had seen them in Germany many years ago very common .peace and good luck clammy