Swimdaddy,

Yes, I have a check valve on the return side plumbing of the solar panel. As I am using Flex PVC that will connect to rigid PVC at the valving manifold I will be using PVC Unions that can be disassembled. With this said, I like your thought to simply fill a bucket and adjust flow accordingly via the valve until I can at least determine flow rate (gpm) at various valve settings.

CarlD,

Although I completely agree with your second sentence, without knowing the pressure that the panels can tolerate, or a method to measure such pressure, I think that I will use the manufacturers gpm rating as a starting point and measure flow via Swimdaddy's suggestion.

Thank you both for your suggestions!