How to turn on the power
From HSG Wiki
Upon entering the space the power needs to be turned on.
Flipping the light switch signals that someone is in the space. You will hear a couple of relays clicking which will enable power and startup the barsystem.
To turn off the power upon leaving the space, hit the big red button behind the door which will close down the barcomputer and turn off the power to other systems. This process takes a few minutes to complete. Make sure not to flip the lightswitch again after having hit the red button or the shutdown procedure will be aborted.