FREQUENTLY ASKED QUESTIONS
Q1: My industrial vacuum pump was expensive. What is the most important thing I can do to maintain it?
A: Insure that the vacuum pump oil is in good condition, or change the oil as necessary. Dirty or contaminated oil can cause severe damage to your vacuum pump and/or your vacuum process. Make sure all your accessories and components of your vacuum pump are correct. Otherwise, these types of issues might cause pump efficiency problems.
Q2: Can I use my industrial vacuum pump to evacuate oxygen tanks?
A: No, never pump even low concentrations of oxygen with a hydrocarbon oil filled pump. Oil sealed vacuum pumps must be built and treated for oxygen service, when using special hydrocarbon-free oil. Mixing an oil filled pump with oxygen can result in an explosion.
Q3: I see some smaller exhaust ﬁlters are a lot cheaper than larger ones. Can I use these instead?
A: Never use an exhaust filter smaller than is recommended. This can cause a restriction in the system, with air coming in the pump faster than it can exit. Not good.
Q4: Is there anything special I need to do when changing pump oil?
A: When changing your oil, run the pump for 20 minutes or so to warm it up. Then drain and change the oil as the warmer it is the easier the flow from the oil case.
Q5: Is it OK to turn my pump off while the line is under vacuum? I heard this could cause a problem.
A: Do not leave pumps under vacuum when you shut it off, if possible. If you are not using the pump, vent the intake line prior to or right after cutting the power.
Q6: I was installing a new pump the other day. When I ﬁrst plugged it in, a lot of smoke came out the exhaust. Will this stop once I connect up the intake and exhaust lines?
A: Never run industrial vacuum pumps without it pulling a vacuum on something. A wide-open intake causes a huge load of air to continue blowing through the pump. Hence the oil smoke.
Q7: When is it best to check the oil level?
A: Oil levels should be checked and adjusted while pumps are running. If the levels appear to be running low when not operating...who cares? The vacuum pumps arent running.
Q8: We are installing a 3-phase vacuum pump. I know rotation is important but how best to check it?
A: On pumps driven by a 3-phase motor, check rotation upon installation. 'Bump' the starter briefly while observing the motor fan. Should the pumps be spinning backward, reverse any 2 of the 3 power wires (with power off) then recheck?
Q9: What causes smoke to come out of my pump? It doesn’t do it all the time, but should I be worried?
A: Smoke (oil vapor) coming from a pump exhaust means you probably have an air leak. Remember, smoke out = air in.
Q10: What's the deal with vacuum readings? Some guys talk about 0-30” and other guys talk in microns. Which is correct?
A: 0-30" mm is the normal range for a vacuum pump. 30” is all there is, so beware of someone selling a pump that can go over 30”. Not possible. When using a high vacuum gauge, essentially, the 30th inch of vacuum is split into tiny pieces, called ‘microns’ or ‘millitorr’. On this type of gauge, unlike the 0-30” gauge, the smaller the numbers, the better the vacuum. i.e. 5 microns is better than 10 microns.
Q11: How can I tell if I have a bad vacuum pump vs. a leaky system? They are all tied together.
A: Test your vacuum pumps by itself, before trying to vacuum test the complete system. This is most easily done by temporarily mounting a gauge directly on to the intake of the pump. This gives you the best / most accurate idea of pump performance.
Q12: When should I be changing my vacuum pumps' oil?
A: Check your vacuum pumps' oil for color, clarity, and level before starting your process and regularly during use. If you can, drain a ½ cup of the oil and look at it periodically. When it starts getting discolored or has an odor, it is past time to change it.
Q13: Is there a temperature range on the vacuum pumps? Ours run in a closed room, which gets pretty hot.
A: While each vacuum pump is different, about 158F (70c) is as hot as you want to get. Always try to keep it cool. Any pump’s natural enemy is heated and should have a supply of fresh air. If it is enclosed, use a fan for cooling otherwise try to install it in an area with open air. The high heat will lower the viscosity of your oil, hindering its ability to pull a good vacuum. If your vacuum pumps don’t pull a good vacuum, things can deteriorate rapidly.
Q14: Some people swear the Edwards E2M30/28 is the best pump ever, while others say the same thing about The Alcatel 2021-series. What is the real story?
A: The answer is that both are excellent vacuum pumps. Both have a comparable ultimate vacuum. The difference is the Edwards displaces 8 CFM more air, meaning it will obtain its ultimate vacuum sooner. However, that is only if the intake line is not restricted, which is on most vacuum ovens. Because the intake tract on the vacuum oven usually cannot flow the same amount of air as the Edwards vacuum pumps, the real useable CFM is restricted down to close to that of the Alcatel pump. This means both vacuum pumps will do a comparable job. So, the Edwards owners think their vacuum pumps work great, which they do, while the Alcatel owner has vacuum pumps doing a comparable job. One last thing to consider, because the Alcatel is a smaller pump it does cost less, meaning the Alcatel is a better value.
Q15: ‘Oil Backstreaming’. I have heard the term but don’t quite understand it. Can you explain it?
A: When air is traveling while vac pumping, as it is when you are evacuating a chamber or an oven, it is darn near impossible for anything to go the opposite direction. However, after the chamber ( or oven ) is evacuated, your system is in what is called the ‘molecular flow’ range. This just means that there is low airflow left in the system that the remaining molecules could conceivably flow rate either direction. The reason this is a potential problem is that oil molecules could float ‘upstream’ from your pump all the way up into your chamber/oven, contaminating whatever is inside.