Recent content by spunkets

The drain line must remain at atmospheric pressure, by plumbing code(law), because otherwise you'd be making a pressure tight connection between a building drain and a potable(?) water source, and the drain system is not designed for pressure applications at all. If your drain gets plugged...

Pressure is independant of volume. Listen to your coworkers and use an intermediate receptacle in the drain line. The receptacle should be open to the atmosphere, so that receptacle simply acts as a funnel.