When accompanied by a Grate and at least one Fluid Pipe, the pump can transmit water through its thick input side to the thin output side. That means that water goes in the thick side and out the thin side. The liquid (Lava, water etc.) is then transmitted through Fluid Pipes to another grate. The grates must be connected to the fluid pipes at the bottom. Currently, the only liquids that can be transmitted are lava and water, as the RedPower machines do not recognize Oil and Fuel as liquids.
The pump itself requires blulectric power (about 75v and 90A of power in one test) as well as a continuous redstone signal to operate. While the pump has enough power and a steady signal, it will continuously pump any liquid it can find on the input side.
WARNING: When pumping a non-viscous liquid, such as water the pump tends to produce more liquid at the output than was present at the input. This may cause any storage containers to overfill, causing a significant cleanup job. The pump is very powerful and capable of filling large spaces with liquid in a few minutes.