Edited:
Tx Mark.
I was actually informed that the low voltage signal input wire does not need a special controller. They stated that the wire can come directly from my Compool Lx220 controller, I think, or maybe the said it was the solar actuator valve. Anyhow, they said that it could be wired to go directly to the pump which would pick up the signal. For the booster, I believe they stated that it would be wired from the Intermatic mechanical timer. It sounded similar with the booster pump like a pool tech had stated that the EcoStar could do. He had stated something about setting some "fireman toggle/switch" on the Intermatic mech timer with the low-voltage wire run to the Ecostar. Maybe that's the same concept the Pentair tech was referring to?
Anyhow, now I'm not sure what to think Mark if you're right. In one aspect, I wonder if this low-voltage signal input would be necessary. But, perhaps it would be with needing the pump to communicate at least with solar. Perhaps I could explain my thought process better with an example. When reading the following, the questions at hand are: would low voltage signalling do anything different than the pumps' time clock/programs would with changing speeds? Why bother w/ the low voltage signalling if the VS pumps have a time clock/controller on them that could allow multiple speeds (the Pentair Superflo & Hayward MaxFlo allow 3 speeds; the EcoStar allows I think 4-8)?
Example: In the summer, right when the pump comes on, the solar may already be on. Let's say pump comes on at 1000, but the solar actuator may have already turned on by 0900. As such, speed 1 will need to be higher than normal to compensate for pumping to the solar on the roof right away upon start up. Then, speed 2 will have to be even higher because then that would be the short duration w/ both solar and the booster pump. Lastly, the 3rd and final speed would have to be the same as speed 1 as the solar would still be on.
So, again, w/ low voltage signalling, the solar could inform the pump that solar is on & we need to ramp up speed, but this would only work if the pump is already on. W/ out the low voltage, then I would just have to estimate when the solar is on and program that accordingly so that the pump has a high enough speed to get it to the solar on the roof. Problem w/ this, if it is not timed correctly and the solar is on, then if the speed is not sufficient when the pump first comes on, the solar panels won't prime & air would be produced through the system. I just don't see how the low voltage signalling could be that much more helpful. Am I missing something (hopefully, this time it was more clear)?