Hydraulic seperator ...how much does pump placement matter?

icy78

As the title asks.
Is there a problem if pumping into the Seperator on the boiler side? (Other than reduced air removal possibly)
Still pumping away on the loop side.
Still hot on top and cold on the bottom.

And...can the extank be plumbed to the same port as the air vent? Teed off below it.
TIA

hot_rod

Like this?

If the boiler prefers the circulator pumping into it, high pressure drop style boilers, this works fine.

I like the expansion on either return "blue" connection at the bottom. It's placed in the cooler fluid. It would work connected on the top connections or into the convince port up top. Try not to pipe it directly off the bottom port, it will get dirt and debris.

I like the indirect tank piped directly to the boiler like this, no need to go thru separation and possible temperature blending. with the appropriate circ of course.

icy78

Like this Bob.

hot_rod

yes, but I prefer the expansion tank and fill valve connection on the bottom. Fill valve can tee into the expansion tank connection, a tee above the exp tank nipple, for example.

Expansion tank with connection up, ideally.

icy78

Ok That makes sense. Have the tank (bladder) away from the hottest water and NOT on the drain connection due to dirt?

And to be clear, its OK to pump into the Hydraulic Seperator ? I didnt see that senario anywhere on your site . We have a site where it's almost a "have-to-plumb-that way"

TAG

NIce -- how do you determine the pump size -- using those "quicksetter" balancing valves?

That's a nice simple layout

ScottSecor

@icy78 we made the mistake of piping the expansion tank and feed-water off the bottom of the hydro-separator the first time we installed one. Needless to say, we don't do it that way anymore.

As Hot Rod suggested in his diagram works best. I realize this method adds another large diameter tee to the materials list, but in the long run it to outperform the other methods. You'd be surprised at the amount of debris, silt and metal chips that end up in the bottom of the hydro-separator.

hot_rod

The distribution, secondary circulator is and ECM type delta P.

Open all actuators, say the design calls for 1/2 pm per loop X 5 loops adjust the quick setter to 2.5 gpm. As zone actuators close the delta P circulator will adjust accordingly.

You still want to size the circulator close to that 5 GPM , both manifolds flowing, total load, even if it modulates.

icy78

Thank you for the info everyone. One thing I would still really like to know .... is it okay to pump the hottest water INTO the separator?
I would think that this would encourage the building Loop pump to pull the hotter water into itself rather than mixed water (at low load conditions) from the separator so would that, or is that a viable concern? Or is it basically a wash?
Not worth worrying about?
I will say that all the pics and diagrams show boiler pump, pumping into the boiler, away from the separator and the building loop pump, pumping away from the separator on the hot side . It makes sense.. However I can find nothing that recommends this type of piping other than the quantity of pics LOL.
@hot_rod ?

hot_rod

The temperature going into the separator will be the exact same regardless if you have the circulator on the sep supply (top) or return (bottom). Same for the flow rate.

The whole concept of a separator is the barrel dimension is large enough that there will be no pump interference or crossing over of flows if both circulators are up top, at the bottom, or one on supply and one on return.

Circulator mounted at the bottom port pumping towards the boiler will be in a cooler fluid, like I mentioned about the expansion tank. Not a huge deal, but why not?

The circulator on the bottom pumping towards the boiler is for the boilers benefit, not the sep.

icy78

> @hot_rod said:
> The temperature going into the separator will be the exact same regardless if you have the circulator on the sep supply (top) or return (bottom). Same for the flow rate.
>
> The whole concept of a separator is the barrel dimension is large enough that there will be no pump interference or crossing over of flows if both circulators are up top, at the bottom, or one on supply and one on return.
>
> Circulator mounted at the bottom port pumping towards the boiler will be in a cooler fluid, like I mentioned about the expansion tank. Not a huge deal, but why not?
>
> The circulator on the bottom pumping towards the boiler is for the boilers benefit, not the sep.

Thankyou Bob.

hot_rod

If you want to zone with circulators, it could look like this. Not different size circs. The key is them header pipe needs to be sized large enough to supply all those circs total flow requirement.

An example of one circ on return, multiple on supply from the sep.