Flowmeter Placement Questions

[BigDave]

I do like the operating simplicity of the VF. How accurate is it's flow measurement? I presume that it maintains flow by measuring flow and adjusting the speed to maintain flow.
I'm thinking about the Hayward ECO-Star Variable Speed with Safety Vacuum Release System. I believe that I can connect the GoldLine 235 solar control unit directly to the pump to run at pre-defined speed and that I would need a pentair control unit to get the solar control system's signal to the pentair pumps.
Am I wrong?

[mas985]

The VF does not measure flow directly but calculates it from a wattage measurement and an RPM setting. The three parameters of GPM, RPM and Watts have a direct relationship so if you know two, you can determine the third. It is probably much more accurate than any of the other measurement techniques that we have discussed.

As for the control of the pump, you need a Pentair controller if you want full control over the speeds.