QuickPit Venting Motor
The QuickPit venting motor is installed outside of the building where it expels flammable gases out from the bottom of the pit to the outside air.
Some municipalities will require venting your pit, so you need to ask them directly. You don't want to have to break-up and replace concrete to lay the PVC lines.
QuickPit Vent Suction Tube
(This picture is a bit dark)
What you are looking at is the back wall of the pit, which is covered by the stairs.
The large diameter PVC pipe connects to the outside pump. The diameter of the pipe in the pit is determined by engineering.
The PVC pipe vent can be installed wherever local ordinances required. Under the stairs is most convenient.