Yo.
I've been trying to build a pump stack, and I learned from the wiki that the pumps can supply power to each other by stacking them correctly as follows:
a pump that is, say pumping from east to west must5 have a pump directly over it pumping from west to east. In addition, the pump on top must have a channel/hole directly underneath its "output" square, such that its output square has nothing between it and the intake square of the pump beneath it.
I think I have this setup; after all, I can't build a screw pump if the hole in the floor is on the wrong side, so it isn't like I can accidentally have the hole over/under the wrong part of the pumps.
I currently have it so the pump on the bottom is pumping west to east, and it has access to a magma source. I confirmed this by hand-pumping it (The dwarf in question was lucky to escape that one alive!) and the pump above pumps east-to-west. The above pump has a hole in the floor directly underneath its output square which is directly abov the bottom ones input square.
According to the wiki, they should be "connected" for power purposes, so I tested this by hand-pumping the topmost one, but this does not draw magma from the lower one. In fact the lower one doesn't appear to be powered when I do this.
It shoudl be noted the top pump has no hole near its intake, so it can't draw anything up. The reason for this was to test their ability to power each other without drowning the dwarf working the upper pump in magma.
Could someone tell me where I have gone wrong? Is it necessary to have the top pump have a hole for drawing magma before it will power the bottom one?