I recently had a large pool built after doing some deep research on past posts in this forum. I am facing an unexpected issue:
I spec'ed the manifold at 4" diameter, along with 2" returns, and oversize filter, and put in a Pentair variable speed pump. The outcome is great. I can circulate my 30K gal pool on 125W usage for the pump, with 0 psi measured pressure at the filter, and I am very pleased with this great result.
The bypass for the heat pump and salt cell, however, is only 2", because that is what the heat pump requires. The outcome is that, in order to insure enough water flow through the bypass, I end up having to tighten the manifold exhaust valve (main valve) to "almost" closed, thereby losing the advantage of my 4" manifold.
I understand, of course, that the 4" manifold also benefits me due to less friction. But I would really like to be able to leave the main valve open to take the full benefit of my 4" manifold. What is wrong in the design? Is there any way, short of an accessory pump for the heat pump bypass, to allow me to open that valve? I did some calculations about adding a pump for the bypass, and figured I would lose a lot of my power savings by doing so.
Any thoughts? I can't think of any solution.