Guy,
Since it is a VS pump, the pump should get constant AC power from a breaker.. All the programming to turn the pump on and off should come from inside the control head.
If there was some kind of programing error in the pump, you would think that it would be constant.. As in every Saturday at X hour the pump starts.. I can't see a programming error be intermittent. If this were my pump I'd want to monitor and see if the problem is repeatable..
The only other thing that might cause the problem is that the power to the pump is intermittent.. Maybe a bad connection of some kind, and that when the pump sees a reconnection of power, it goes into the priming mode.
Once the pump starts, when it should not be running, does it shut off on its own? Does it run for some fixed time and then shut off?
Is your waterfall scheduled to run each day at a specific time, or do you just manually turn it on when you want to use it. If you manually turn it on, do you press a button on the pump itself, or do your have some kind of timer or switch??
Thanks,
Jim R.