Liquid Ring Vacuum Pump Troubleshooting

Though our vacuum pumps are designed to operate efficiently and effectively for years without quality issues, sometimes problems may arise.

This chart highlights various trouble shooting tips for some of commonly used liquid ring vacuum pumps.


Possible Causes


Low suction capacity


Excessive clearance between impeller and disc

Adjust clearance

Seal leakage

Compress or replace seal

High seal water temperature

Increase water supplying

Pipeline leakage

Tighten flang bolts,replace gaskets or re-weld fracture

Low vacuum levels

Flange joint gas leakage

Tighten flange bolts or replace gaskets

Pipeline fracture

Re-weld or replace pipeline

Seal leakaging

Compress or replace seal

Hot temperature water ring

Lower supplying water temperature

Insufficient water supply

Increase supplying water

Water ring temperature rises because parts friction

Adjust or re-install parts

Vibration or noise

Anchor bolts loosing

Tighten anchor bolts

Foreign object friction inside pump

Check and take out the foreign objects

Impeller break off

Replace impeller


Open the suction pipeline valve

Hot bearing

Insufficient lubrication oil

Check oil lubrication and refill if needed

Overtight packing material

Loosen packing material properly

No or insufficient sealing water

Feed sealing water or increase water supply

Over tight bearing or bearing bracket fitting causing friction

Adjust the clearance between bearing and shaft or bearing bracket

Hard starting up

Pump rust due to longtime not running

Rotate the impeller manually or with special tool

Tight packing material

Loosen packing material gland

Deflected friction between impeller and pump casing

Reinstallation and adjustment


Subscribe to receive more articles about pump and vacuum industry.


Leave a comment

Please note, comments must be approved before they are published