solar heater

[CarlD]

Al is right.

But there is a paradox. The more water you can flow through the panels, the less of a temperature differential you'll see. This leads people to believe that a lower flow is better.

WRONG!!!!!!!!

The ONLY reason to limit flow is that some part of the plumbing (the pump, the valves, the hoses or the panel itself) is likely to fail from too high or too low pressure. The more water you can flow, the more efficient your system will be and the more heat you'll transfer. Your panels, at peak efficiency, on a blistering hot sunny day, will be no warmer than your pool. While you never achieve this, it is quite common for panels to be cool to the touch when you expect them to burn you.

That's because to warm your pool you are working on transferring HEAT, not temperature. BTUs are what count, gang, not degrees.