[wtallis]

If there's a limit on how much positive pressure a pump can generate to push water above itself, then what approximately is the value of that limit, and how would a pump capable of exceeding that limit allow you to construct a perpetual motion machine?

[na85]

The limit depends on the pump. If you're pushing water uphill the weight of the water will eventually equal the maximum pressure that the pump can deliver and you won't be able to push any further.

This is basic high school physics.

[wtallis]

You've completely misunderstood this this conversation. The limit on the height from which a pump can suck water is a limit that applies to all pumps, no matter how powerful. There's no comparable limit for pumps pushing water upward. Yes, each particular pump will have its own limits, but there's no comparable overarching fundamental limit.

[zaroth]

Thank you, you’ve explained this better than I could