Troubleshooting Low Vacuum Levels

Low vacuum levels are one of the more common problems/symptoms experienced in vacuum systems. The word "symptom" is really emphasized here, because the difficulty is rarely caused by the vacuum pump alone. However, the vacuum pump often gets changed out, only to discover the problem still exists. 

First, recognize that vacuum levels are a measurement of resistance to airflow, where the airflow is induced by the vacuum pumps and the resistance is the various dewatering processes and system piping. Changes in resistance to airflow are caused by various process variables, including machine geometry and machine speed.

The following sections discuss some typical causes of low vacuum levels, including:

Open valve in the vacuum line or header; plugged screens at the vacuum pump inlet; uncovered barometric seal leg from a pre-separator; and low seal water flow at the vacuum pump.

Plugged screens at the vacuum pump inlet

Uncovered barometric seal leg

Low seal water flow