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Self-Care Guide for Small Oil-Sealed Rotary Vane Vacuum Pumps

The way you start and stop a vacuum pump can affect the lifetime and maintenance intervals of the equipment. In the current scenario where researchers may not have been able to maintain or run vacuum equipment as usual or where equipment has been stopped for some time, we believe it is important to review the condition of your vacuum equipment before restarting operation.
Below you will find a generic list of recommendations for the return to operation of small oil-sealed rotary-vane laboratory vacuum pumps, as well as a list at the bottom of useful components for carrying out these vacuum pump health check operation.

Disclaimer: The recommendations below are generic considerations for oil-sealed rotary-vane laboratory vacuum pumps. They are not meant as an instruction manual and they do not replace nor supersede your system's and/or equipment's instruction and operation manuals. Always follow the safety, operating and maintenance instructions from the equipment manual, which are specific to your equipment. We accept no liability nor responsibility for the incorrect use of your vacuum equipment nor for failure to follow your vacuum equipment's instruction and operation manual. We reserve the right to add/modify the recommendations below at any time.


  • Follow all safety precautions indicated in your existing vacuum equipment and system instruction and operation manuals and obey any local and national safety regulations.
  • The recommendations below assume that the vacuum pump is suitable for the application and that it has been installed safely and correctly, both electrically and mechanically.
  • If pumping in an Atex (Explosive Atmospheres) classified area or if pumping flammable or pyrophoric gases, take the corresponding precautions as per the equipment/system instruction manual as well as local/national regulations. Safely inert and isolate the equipment before performing any maintenance operation.
    If you are not 100% sure, ask.
  • Do not touch or inhale the thermal breakdown products of fluorinated materials which may be present if the pump or seals have been heated to 310 °C and above. Fluorinated materials (such as Viton®) are safe in normal use but can decompose into very dangerous substances if they are heated to 310 °C and above. The pump may have overheated if it was misused, if it malfunctioned or if it was in a fire. Material Safety Data Sheets for fluorinated materials used in the pump are available on request: contact your supplier.


  • Ensure that you are familiar with the vacuum installation and the gases and solvents being processed by the pump before manipulating the pumping system, and take the necessary and corresponding precautions.
  • Wear the appropriate safety-clothing and personal protective equipment when coming into contact with contaminated components. Dismantle and clean contaminated components inside a fume cupboard.
  • Vent and purge the vacuum system before carrying out any installation or maintenance work. Prevent any part of the human body from coming into contact with vacuum.
  • Allow the pump to cool (so that it is at a safe temperature for skin contact) before starting maintenance health check work.
  • Take suitable precautions to avoid the inhalation of oil mist and excessive skin contact with pump-oil, as prolonged exposure can be harmful.
  • Disconnect and isolate the pump(s) from the electrical supply so that they cannot be operated accidentally.

Hardware Checks

Read the safety section and your equipment manual before modifying, adding or removing vacuum components.

  • Check o-rings and seals and replace if they are damaged or deteriorated.
  • If fitted, check if the inlet filter is clean and clean/replace if necessary.
  • Check the inlet and exhaust seals and connections.
  • Check that there are no restrictions or blockages at the inlet and exhaust of the pump.
  • See below list of most commonly-used spares that may be useful to update the installation.

Oil Lubrication & Gas Ballast

The functions of oil in rotary vane pumps are to: seal, lubricate, cool and protect parts from rust and corrosion. Pump performance and lifetime require that the oil is replaced when necessary. After long periods without use or supervision, the lubricant oil inside the pump may have degraded.

Oil deteriorates over time depending on a number of factors, such as the conditions in which the pump is operated (pressure, cycles, temperature etc.) as well as the chemicals, vapours or particles present in the application.
The colour of the oil indicates the degree of thermal ageing and therefore the remaining useful life of the oil in your pump. Oil condition and oil level and oil quality will affect pump performance as well as pump life.

The oil in the pump should be clear; if the oil is cloudy or discoloured, it is contaminated with process vapours or has degraded.

If possible, measure the pump vacuum before, during and after changing the oil and/or running the gas ballast sequence.

Oil Condition

The above picture shows the process of oil degradation over time and acts as a good indication of when oil should be changed in a rotary pump. Ideally, oil should be changed before it reaches stages 5 or 6. If allowed to deteriorate to stages 9 or 10, the pump may become damaged and a full service and decontamination will be required.

Oil Quality

The quality of oil used is also important for a vacuum pump.There are several characteristics that distinguish high-quality vacuum pump oils from standard vacuum pump oils.

Standard oils don't specify vapour pressures or specify vapour pressures at ambient temperature only. Vacuum pumps operate above ambient temperature, and high quality oils specify the vapour pressure at the real working operating temperatures which should be lower than the pump's ultimate vacuum at those temperatures.
The difference between high quality and standard vacuum pump oil at real working temperatures can be several decades in vacuum level.

High quality vacuum pump oils, as well as having the right viscosity and basic properties, undergo specific manufacturing treatment processes and incorporate special additives that standard oils do not have. In practice, high quality vacuum pump are more chemically resistant, work better at high temperature and low pressures, degrade slower, emit less oil vapours and last longer than standard vacuum pump oils, sometimes more than 2 o 3 times longer. Which is cheaper in the long run, and generates less waste oil.
We recommend using high quality vacuum pump oil for every application.

Oil Change

Read the safety section and pump instruction manual before performing an oil change.

Note: When performing oil changes, if the pump can start normally and it is safe to do so, it will be easier to drain out the oil after running the pump for 10-30 minutes to warm the oil, then disconnect the pump from the electrical supply (this lowers the viscosity of the oil and enables it to be drained from the pump more easily) Allow the pump to cool (so that it is at a safe temperature for skin contact) before changing the oil.

If the oil is very contaminated or degraded but has not yet reached stages 9 or 10, replace it with new oil following the procedure indicated in the pump instruction manual. Depending on the degree of degradation and contaminants inside the pump, it may be necessary to drain the oil and replace it more than one time. We recommend filling the pump with oil to just below the maximum level line as indicated in the instruction manual.

Manual Gas Ballast

Refer to the equipment instructions. Safely inert the pump and isolate the pump inlet before decontaminating the oil with gas ballast. *If running automated gas ballast, please contact us or your vacuum supplier.

If the oil is clean or lightly contaminated, or once the contaminated oil has been replaced with new oil, we recommend running the pump for some time with the pump inlet isolated - with a closed valve or a blanking flange - and the gas ballast opened. Operating with gas ballast will help remove some contaminants from the oil, and in the case of clear or new oil it will help out-gas humidity present in the oil from the ambient.

Ideally, operate the pump until the oil is clear and check the oil level at regular intervals to ensure the level is correct and that the system is working correctly. For long periods of unattended operation or where gas ballast is used continuously during normal operation we recommend considering an exhaust mist filter accessory and in some cases also an oil return kit to recover exhaust oil mist back into the pump where applicable.
Return the gas ballast valve to its normal safe operating position.

Oil Loss

Several factors can affect the rate of oil loss in a vacuum pump, such as: running pressure, temperature, number of cycles, gas-ballast operation etc.
Consider using a high quality exhaust oil-mist filter and in some cases also an automatic oil-return kit to minimise oil consumption and extend maintenance intervals.
Replace your filter internal elements when necessary to keep the filtration properties active.

Final Checks

If the oil is clear, the oil level is correct, and the vacuum performance is insufficient:

  • Check the inlet and exhaust seals and connections.
  • Check that there are no restrictions or blockages at the inlet and exhaust of the pump.
  • Check if you are using high quality oil.
  • Check if the gauge is faulty, contaminated or has lost its calibration.

If you are still having difficulty or need assistance with your vacuum equipment, you can contact us by filling the form at the bottom of this page.

Useful Components for Small Rotary vane Pumps

Basic Components

Ultragrade Oil 15

Ultragrade Oil 19

Centering Ring

Inlet Strainer

Clamping Ring

Hinged Clamp

Swing Clamp

Nozzle Hose Adaptor

Vacuum Measurement

P3 handheld Pressure gauge

APG100 Pirani

ADC Pressure Display Controller

T Piece


Filters & Spares

Exhaust Mist Filter

Oil Mist Element EMF

Oil Odour Element EMF

Oil Return Kit

Foreline trap


Clean & Overhaul Kit RV

Blade Kit RV