Vacuum Pump Low Vacuum Reasons and Troubleshooting

Vacuum Pump Low Vacuum Reasons

First, the vacuum pump itself leaks


  1. The sealing ring is leaking.

The sealing condition of all sealing parts should be checked, and the damaged sealing ring should be replaced.


  1. Gas ballast valve gasket is damaged or not tightened.

The gasket should be replaced and the gas ballast valve should be tightened.


  1. The exhaust valve is damaged and the seal is not good

The valve plate should be replaced.


  1. When the intermediate plate in the vacuum pump is pressed in, the interference is too large, causing the vacuum pump chamber to deform and leak air.

The vacuum pump cavity should be repaired or replaced.


  1. Air leakage due to poor oil seal on the end surface of the vacuum pump.

End caps should be removed, inspect for debris or unevenness, and clean or repair.


Second, vacuum pump oil problem


  1. If the oil level is too low, add enough oil to the center line of the oil mark.


  1. The oil is stained and the oil quality deteriorates.

Replace with new oil.


  1. If the oil grade does not match, the vacuum pump oil of the specified grade should be replaced.


  1. The oil circuit is blocked, and the proper amount of oil is not maintained in the vacuum pump chamber.

The oil intake of the oil circuit and the oil valve should be checked to keep the oil circuit unobstructed.


  1. The filter screen of the air inlet is blocked.

The filter should be removed, cleaned, and then installed.


  1. The spring of the rotor is deformed or broken and the action of the rotary vane is not working.

The deformation of the spring should be repaired or replaced, so that the rotor accumulators can be well matched.


  1. The vacuum pump temperature is too high.

  • The temperature of the pumped gas is too high.

The gas should be cooled before entering the vacuum pump.

  • Inhalation of hard objects causes wearing of the vacuum pump body.

The vacuum pump should be disassembled to remove hard objects, and the scratched parts should be repaired or replaced.

  • The cooling water flow of the vacuum pump is not enough.

The cooling water flow should be increased.

  • Improper assembly will cause displacement of the rotor axis, resulting in single-side wearing.

It should be disassembled for inspection and reassembled.


  1. The clearance is too large due to poor machining or wearing. The correct clearance between the vacuum pump chamber, rotor, rotary vane and end cover should be checked and repaired or replaced with the specified accuracy requirements.


  1. Friction heats up during vacuum pump operation, causing the temperature rising too high, which makes the vacuum pump oil thinner and the sealing performance deteriorates.

It should be cooled by cooling water or an electric fan, and at the same time, check the clearance of the relevant parts and repair or replace it according to the specified accuracy requirements.


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