This step continues the retort cooling process. Cooling water continues to flow into the Process Vessel and flows out through the drain valve, which controls the level. Control is removed from the Pressure Relief valve, releasing pressure by opening the vent valve (note: pressure may be steadily released using ramp control employed in a second Pressure Cool step). When the atmospheric cool time is completed, and an established temperature setpoint in the Process Vessel is achieved, the step ends.