Vertical Manifold and closely spaced Tees - Good or Bad?

[MNBobcat]

I have an OWB. I am in the process of installing a Primary/Secondary system with the primary pump in the house rather than on the boiler. I'd like to locate the primary pump for my system as near to the basement floor as possible to take advantage of the natural pressure to be gained by having the pump as low as possible below the boiler. My pex enters the basement by the ceiling.

My plan was to put a 90 on the pex source and come down the wall, through the manifold and then into the return. I'm wrestling with a question and would appreciate some advice.

If I mount the pump by the floor I assume I'd have to use a couple of 90's to make a loop and come back up the wall and then use a 90 to go into a horizontal manifold. I would then need 2 more 90's after the manifold in order to connect into the return. I'm trying to keep my head as low as possible. All of those 90's won't help.

I was wondering what the ramifications are if I were to mount the manifold in a vertical position with the secondary pumps coming off the side rather than above or below? Would I introduce problems with ghost flows? Bad idea?

Forgetting my question about the vertical manifold, if you were designing this primary/secondary system where would you position the primary pump on the wall and how would you plumb things? I have to keep the primary system as free of 90's, and other things that would increase head, as possible. The pex size for my main loop is slightly under sized.

Thanks!

 

[Nofossil]

I'm having a hard time visualizing your question. A picture is worth a thousand words - even a sketch on a napkin photographed with a cell phone.

 

[ewdudley]

I have an OWB.

...

Forgetting my question about the vertical manifold, if you were designing this primary/secondary system where would you position the primary pump on the wall and how would you plumb things? I have to keep the primary system as free of 90's, and other things that would increase head, as possible. The pex size for my main loop is slightly under sized.

Thanks!

Presumably you're going to have flow check in your secondaries, so those circuits will be invisible to the primary loop when they're inactive, and they will draw correctly independent of manifold orientation when active (or so I would imagine, keeping in mind that I've never been there, never done that). Just be sure to sequence the secondaries to have loads requiring the hottest water drawing before ones that can cope better with not-so-hot water.

As for the primary pump, if you're looking at greater than normal head pressures out of the pump due to marginally sized piping, you need to be sure you're happy with the pressure drop you're going to see way back at the OWB. Google for "point of no pressure change" and be sure you understand the ramifications of having your pump located any further than necessary from the system pressure reference point.

--ewd