Liquid Pipes are a one way pipe that can handle a maximum of 10,000 fluid (10 Buckets). They will only accept fluid if they do not contain any fluid in them so they will never constantly drain fluid. Blue side is Input and the Red side is Output. You can rotate the Liquid Pipes output by right clicking on it (While not holding a Power Wire). You can rotate the Input side by Right Clicking while holding a Hammer. When placing Liquid Pipes they will orientate based on the side of the block you are looking at.

The Toggle version will only output fluid if there is a redstone signal being sent to it.