While the Pump Room puzzle in Signalis may look intimidating at first glance, it's actually one of the easier enigmas to solve in the game. You just have to know where to look for the solution. 

This quick guide will tell you how to move the water around in the Pump Room to drain the Protektor Bathroom and reach the area below, where you'll find several important story items. 

If you're here because of the Pump Room puzzle, it's likely that you already have the Pump Room key. But for the sake of thoroughness (and not assuming that everyone that's made their way to this guide has found it), you can pick the Pump Room key up in the Protektor Bathroom off of the West Corridor in the New Medical Ward. 

Take the Pump Room key from the Protektor Bathroom, cross the West Corner down and right, and enter the Pump Room itself (it's the room south of the Waiting Room with the 5-Lock Door). Inside, you'll see tanks and a water-level monitoring station at the top of the room, as well as two desk on the far right of the room. Interact with the not on the table without the light. 

This note tells you exactly how to solve the Pump Room puzzle, explaining how to move the water from each tank to drain the Protektor Bathroom. The goal here is to fill Tank A halfway and Tank B three-fourths of the way while emptying Tank C.

In lieu of taking a picture and referencing that (because it's difficult to remember), here's what the note says, with a few formatting additions and directions to make it easier to understand: 

With Tank A full, here's how to equalize the reservoir: 

If you've followed the directions correctly, a small cutscene will play as soon as the water levels are equalized properly. With the Pump Room puzzle solved, you can now use the hole in the floor of the Protektor Bathroom to reach a new, lower area and several important items and keys necessary to move forward. For more, such as how to solve the gas valve puzzle in the incinerator and how to engrave the Blank Key, click the links or head to our guides hub.