Solar Panel plumbing and flow rate

[Slachey]

Guys,

My 4 x 20 panels have the internal manual valve that allow one panel to divert flow down one half, then the 2nd half, but I am not using them in this fashion. The (2) panels are installed horizontally and in parallel, one above the other, with the left side headers coupled and the right side headers coupled. The inlet is at the lower left on panel 1 (lower panel) and the water flows through the left header of panel 1 and panel 2 before going through the panels and discharging at the upper right header of panel 2 (upper panel). I believe this is the proper configuration based on what I have been reading on this site. It has been cloudy here, so I have not been doing much testing, but there was a few hours of sun over the weekend. The panels seemed quite hot when the 3-way valve was adjusted to ~ 25% opening towards the panels and 75% towards the pool, so I kept adjusting the valve until the panels become cool. This occurred when the valve was nearly 100% towards the panels. I also checked the filter gauge and did not see any increase in pressure at all. In the pool, the water coming from the return was ~ 2 degrees warmer than the surrounding water, so it sounds like it is working properly. The fact that there is no pressure rise is quite surprising to me. Is this common? My pump is a 2 hp single speed unit.

[mas985]

At 100% flow, no pressure rise would be very unusual. Almost impossible given the panel size. Are you sure that there is no other path for the water to flow besides through the panels? Also, is the pump running on full speed? On low speed of a two speed would be very low pressure rise.

[Slachey]

The pump is a 2 hp single speed unit as I mentioned in my post. My plumbing manifold is in a horizontal "H" configuration. On the upper horizontal leg, the flow is from right to left from the filter. In the middle of the leg is the 3-position diverter valve, and to the left is the plumbing to the panels. On the lower horizontal leg the flow is from left to right from the panels and through a "T" section. To the right of the "T", the flow goes back to the pool. The vertical leg between the diverter valve and "T" is the bypass, allowing flow directly back to the pool. I have the diverter valve adjusted so that there is zero flow going through the vertical leg and 100% flow going to the left towards the panels. Location wise, the pump / filter is located directly next to the pool and I have 50' of flex PVC going to and from the 20' long panels.

[mas985]

I should have asked this before but what is the make/model of the pump?

Also, where are the panels installed roof (1 or 2 story) or ground?

Filter pressure with solar on?

[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.