Solar Panel plumbing and flow rate

[Slachey]

I am at the office, so I don't have the details on the pump, but I believe it is a US Motors 2 HP pump. The panels are installed at ground level on a 30 degree rack that I built.

Thanks for your insight on this!

[mas985]

US motors is the motor not the pump. The pump wet end would be made by someone else (Hayward, Pentair, Jandy, Intex, etc).

[Slachey]

I will have to check when I get home. I know it is a Columbia 22" sand filter, but I do not recall the pump name on the motor.

Thanks again.

[Slachey]

Mas985,

I confirmed that the pump is a Columbia PMX 2HP single speed pump.

Again, thanks for the help.

[mas985]

That is a very low head AG pump so that explains the low PSI rise. It is probably SPL rated (double up rated) so you may need to redirect all the flow through the panels. But what was the filter pressure with all the flow going through the panels?


http://www.columbiapoolproducts.com/2-speed-2hp-pump/

[Slachey]

The filter pressure is ~ 20 psi either through the panels or not.

[mas985]

20 PSI is about 46' of head but only on the return side. Suction side is probably at least 5' of head. That is 51' of head and according to the head curve, you have about 25 GPM so not much flow rate at all. But the head loss in your plumbing is extremely high for the given flow rate (~5x the average pool with 1.5" plumbing). So I suspect there is some issue with the filter or other parts of the plumbing.

Is 20 PSI the clean pressure and has it always been that high?

Have you backwashed/cleaned the filter recently?

[Slachey]

When you say "issue", I am not sure what you are referring to? Note that there is 50' of 1.5" flex PVC going to the panels and 50' of 1.5" flex PVC coming from the panels. The 20 psi is typical, even after backwashing. The flow from at the pool return is very strong, and when I backwash, flow is quite strong as well. I just turned the pump on and checked the pressure gauge prior to starting. It was at 0 PSI.

[mas985]

What I mean by issue is that your pump is a low head pump and 20 PSI is awfully high for a pump like that so something in your plumbing is causing a lot of head loss.

But is the water traveling through the 50' of pipe without solar engaged as well?

[Slachey]

No. As explained in a previous post, I have an horizontal "H" manifold which is located next to the pump, although there is a 8' hose connecting the filter to the rigid manifold.