I think it was more meant to say put any diversions or valves on the output side of the pump. All the magnetic drive pumps are capable of "pushing" water more or less, but restricting the intake of water will burn them out fast.

It is usually a good idea to put a ball valve in-line with the output in any case, so you can restrict if you want to. About a $3 expense.

The 3000 here has a 4 1/2 foot head, and it can start to overrun one of the AGA MegaFlows. I have to slightly restrict it to avoid a perfect siphon forming.

I admit, I like these pumps just a bit better than the Mag Drives, they use a lot less power to do their job.

-Paul