[mike31154]

Always cool to see someone such as yourself trying a new product & a controllable return pump is certainly an option many of us could use! Once something like this gets rolling, often other manufacturers will look to get in on the game provided patents don't stifle competition too much.

Good to hear that you'll be getting some more specs on the unit, particularly the head loss curve. As far as the electrical part of it, seems many products have a lot of technobabble on their web pages to impress & confuse folks in an effort to persuade them that their product is somehow exclusive.

Panworld has been producing DC voltage pumps for some time, but there is no controller, you simply feed the rated DC voltage directly to the pump, same as a standard AC voltage pump. Thing is, our homes are fed 60Hz AC voltage, so to run any DC pump, you need a rectifier to produce the DC voltage. With a heavy duty variable resistor, you could make a simple manual control for any DC driven pump, much like a conventional dimmer. It would take a few more parts & circuits to make this automatic & that's generally where the high cost comes in.

Here's my best guess as to why they talk about pure sine wave with respect to this pump. Looking at the Controller circuit diagram on page 12 of the User Manual, I suspect that the motor itself is a 3 phase AC motor & the only thing DC about it is the Controller itself. The Contoller is fed household 60Hz, 2 phase AC voltage which it rectifies to DC. This DC voltage is then fed to the Control Circuit which actually produces a 3 phase AC or PWM signal. The PWM signal is then fed to the 3 phase Inverter Bridge & finally to the AC motor. This is probably why they talk of the pure sine wave. As I mentioned earlier, the motor itself is actually a 3 phase AC motor being fed a controllable, pure sine wave AC signal from the motor Controller!

Hope this is not too confusing & somewhat informative, I tried to keep it relatively simple and of course it's just my best guess as to how it works based on the block diagram. Bottom line I think is, the relatively high cost of this pump can be attributed to the Controller.

Looking forward to hearing a bit more once you get your hands on these.