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Model: WVP12
Item Title:Oilless oil-free vacuum pump with twin piston 1.15 HP 115 VAC 11.5 CFM for workshop/Science lab setups
S&H: $59.95, Continental USA, S&H varies to other areas and countries.

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What kind of pump do I need:

This is is the first and the most important question any pump user should ask before investing in a vacuum pump. Consider these factors:

1: What is the vacuum level you need?
2: How big is the pump that I need?
3: Oilled rotary vane pump or oilless piston pump?

The first question is the main factor in purchasing a pump, if you need really deep vacuum, expecting in the micron range, you need 2-stage rotary vane vacuum pump, period. Any oilless vacuum pump will not get to 29 inch Hg easily. Single stage rotary vane pump will get more than 29 inch Hg, but hard to get to the micron range, no matter how the pump is rated. The real work application is likely not an ideal system, any single stage pump may not perform as it is rated. The oil in the vaned pumps provide the lubrication and the seal to achieve a deep vacuum. In some application, molecular pumps are needed after priming with a stage rotary vane vacuum pump(s).

How big is the pump you need is determined by the factors of system size and the rate of leaking. If you have a big void space and you need to get to a vacuum fast, a bigger pump should be considered. If the system leaking (or operational leaking, like a pulsator in a milker), a bigger pump should be considered. Most likely, your equipmemnt manufaturer will tell you how big the pump should be. As a user, always pay attention to prevent any leak in line.

Oilless pump may be considered if your vacuum need is less than 25 inch Hg. The oilfree pumps are almost carefree, never to worry about the oil level in the pump, never have to fight with the oil mist problem that is associated with the rotary vane pumps. In the long run, the cost of the oil will add up more costly than investing in a oil-free pump, which is usually more expensive than a rotary vane pump.

We have oiled rotary vane vacuum pumps and oilless/oilfree vacuum pumps. Choose the right pump for your operational needs.

How do I take care of the rotary vane vacuum pump?

For caring of your vacuum pump, ourt Technicians and the factory customer service have concluded, most of the returned pumps are abused or lack of proper care during usage or installation, especially for those buyers using the pumps for workshop and lab setups.
1st: vacuum pump is NOT a vacuum cleaner or Shopvac: It can not tolerate dusts or debris. We have find these materiels in the returned vacuum pumps: glass pieces, metal dusts, wood chips, silicone gel, Epoxy in different sizes and shapes, even nails. If the input air in your operation has dusts or liquid of any type, PLEASE use a and/or filter to remove the contaminents from entering the pump.
2nd, DO NOT run the pump without oil or with dust-filled oil if you are using rotary vane pumps; a burned pump will ruin the warranty. Oils serve as a coolant to the moving parts of the pump and lubricate and seal the parts for air leak. Low oil or dirty oil will cause improper lubrication and cause the pump overheat.
3rd, Get the Right Pump for the Job: VIOT Rotary Vane Vacuum Pumps are primarily designed for HVAC field service, system evacuation jobs. You may use the rotary vane pumps for high vacuum operations like workshop setups, such as vacuum bagging.
4th, Know your system need and your pump: If your operation needs DEEP VACUUM, make sure to get the setup right before using it, leak-prove the vacuum line and the whole system. If you need to keep the flare port, use a female flare connector for the hookup, you can not slide a tubing to the thread and expect to get a deep vacuum. Oilless/oil-free pumps are good for applications where not-so-deep vacuum is needed and the envisonment can not tolerate oil-mist, like in workshop and lab setups and milker machine hookups, but these pump will never get Deeper than 25 inch Hg on Vacuum pressure it will never get to the micron range.
5th, Invest in your system: Right setup prevent problems in the future. Yes, invest in the equipment. so that the pump become a part of the investment of your working system. These things can be added to the vacuum line according to your application: dust filter, Liquid trap(available, click). If the intake air is saturated with vapor of any kind, use a low temperature liquid trap, vacuum tank, control/isolation valve/solenoid, vacuum switch/controller, vacuum gauge, exhaust muffler with hose etc. We do carry some of these add-on parts like the vacuum gauge, control switch, filters and the exhaust muffler, at: http://viot.us/showFAQ.php?model=VPD5

Q:What refrigerant or oil type are your pumps compatible with?

A: Rotary Vane Vacuum pumps are compatible with all refrigerant systems with different oil types in the system. There is no compatibility issue what so ever, and you do not need to worry about cross contamination of one kind of oil to another system either, because the vacuum goes in one direction and there should be no cross contamination if you do not get the vacuum oil sucked back to the AC system. The only issue you may consider is the port size, but this is solved by the use of the right manifold gauge set or other attachment tools, not an issue of vacuum pump.

Note: PLEASE recover the refrigerant in the system before hooking up a vacuum pump. Any pressure higher than atmospheric pressure may blow the pump and void your warranty!

Q:How Do I Add the vacuum oil to my rotary vane pump?

A: Remove the exhaust muffler on top of the vacuum pump, exposed is a hole to the oil reservoir. Add the vacuum oil through this hole. Watch the oil level from the sight viewing glass at the front end of the pump. Remember to put the exhaust/muffler back after adding the oil. If the muffler is supplied with a cap, remove the muffler cap before powering up the pump. Other manufactures may have a special port for adding oil to their pumps, refer to the user manual if different from our pumps.

Q:Do I Need To Change The Oil on the Pump? How often do I need to change the oil?

A: Yes if you have the rotary vane pump. How often? It depends. Changing the oil on a regular bases(say Every 4 months or half year), may extend the life of your pump. I change the oil when the oil is getting a little dark, or after I worked on a burned out system, or when the compressor oil get sucked into my pump. If you use the pump a lot, make sure to change the oil a little more often.

If you have the oilless oil-free pump, you do not need the oil at all.

Q:What general care of vacuum pumps do I need to be aware of?

A: A few things here:
1, Change oil when needed if you have the rotary vane pump,
2, watch the oil level, do not over fill and do not under fill.
3, do not over heat the pump: if you are using the pump at ultra-high vacuum(near the max vacuum), the pump is running at the full power, not only the motor produce heat, the pump generate heat too, lubrication is critical at the full capacity running. Lack of oil will cause the vanes overheat and burn the pump. DO not run the pump at the max vacuum for over 30 minutes.
4, do not let too much moisture or solvents, or debris get to the oil, design a trap on the intake air line, if needed.

Q:What applications your pumps can be used for?

A: Thousands of our pumps of different models are sold in the last decade. Besides AC system evacuation jobs, our pumps have been used in these applications according to what buyers have told us:

  • Shop equipment hook-ups: Molding, lamination/gluing applications; resin infiltration/"pregnant" vacuum bagging: boat/car/airplane body repair jobs(click here and see how); etc.
  • Degassing operations: this kind of operation include: Silicone, applications like this: https://www.youtube.com/watch?v=eHyAhXMj8cc concrete pouring, chocolate casting, with or without a mold. Usually done in a vacuum chamber for dentistry or resin casting.
  • Jewry Making: Epoxy parts together under vacuum(no micro-air bubble in the glue, givinga more desirable cosmetic finish);
  • Dairy Farm Pulsator; click for how it is set up. Dairy farm use for milking(most single stage and large CFM rated pumps: VPDS6 or VPDS12, if you have only a few animals, VPDS3 should do it fine).
  • Lab equipment hook-ups:Dryer degassing, small scale light-duty evaporation and vacuum filtration, etc. but not overnight freeze-dryer, not production scale evaporators, etc.
Any thing else? You have to tell us, so we can extend this list. we have pumps from 1.5 CFM to 12 CFM. If you are in need of a good general purpose pump, we have it for you. if you can not decide on a pump, email me and ask

Q: How do I decide on a vacuum pump? What model is good for my job?

A: It depends on your job. If you are using the pump for an industrial operation, you need a continuous duty or heavy duty pump. if your operation is HVAC evacuations and/or each run is less than an hour, use the intermittent duty or continuous duty pumps. VPDx(where the x stands for the size of the pump for CFM rating) are continuous duty pumps, VPBx are intermittent duty pumps. Pumps are rated on the free air replacement as CFM(cubic feet per minute). Bigger the CFM, larger the pump. How big your pump needs to be? This will depends on how quick the vacuum level has to be reached or the nature of the job. Bigger the void space in the vacuumed system(or the refrigeration system), bigger the pump needs to be. Also, how fast you want to reach to the needed vacuum is also a factor to be considered. Bigger the pump, faster it will reach to the wanted vacuum. You will never regret if you choose the pump one size bigger than you need. Of the same CFM rating, 2 stage pumps out perform the single stage pumps and reduce the time needed to reach to the vacuum level by half. We have pumps from 2 CFM to 12 CFM, a wide range for you to choose from.

Q: What does the micron rating mean? How does it relate to inch Hg vacuum or absolute pressure?

A: Atmospheric pressure at seal level is about 29.92 inch Hg. Any pressure below this number is considered to be under vacuum. However, this pressure vary with the altitude abobe sea level, higher the elevation, lower the pressure. for example, if you live at 2000ft above the sea, the maximum vacuum you can get is -27.8 inch Hg. see this link for details: Air Pressure. So, absolute vacuum is 0 inch Hg, or some may say 29.92 inch Hg vacuum! At very low pressure under vacuum, micron is used. It is an absolute pressure, one micron is defined as 1 micrometer Hg. One inch Hg has about 25,400 microns. 100 micron will be about 29.92 inch Hg vacuum! Deep vacuum pumps are rated by their vacuum levels they can achieve in microns. So, the lower the micron rating, better is the pump, deeper the vacuum it can reach.

Q: Are the repair parts available?

A: Yes, all replacement parts are available for warranty repair. If your pump is out of warranty period, and you need a part to be replaced because of damage or wearing, email me at: Johnm at sign viot.us, we will get you the part for a reasonable price. Make sure you tell us the Model of your pump and what part need to be replaced. There is a picture here if you need to know which part you need.

Q: I am using vacuum pump indoor, I noticed the oil vapor is obvious after a few hours running the pump, do you have a more powerful oil eliminator or muffler?

A: Every vacuum pump has the same "smoking" problem. Some manufacturers use very large and expensive oil-eliminator to help with this situations. We have a new solution, that is an exhaust muffler with tubing connection, if you are planning to use the pump in a closed space/indoor, you can use this exhaust with plastic tubing or garden hose to conduct the exhaust air to an exhaust hood or out door. make sure the tubing will NOT be blocked or give any back pressure to the pump.

just replace your existing muffler with this one and connect the tubing to it with a clamp. DO NOT reduce the the tubing size, make sure the condensed oil is running in one direction, and that does not block the exhaust air way.
This muffler is available at: http://viot.us/HVAC/product_info.php?cPath=27&products_id=212

If your operation does not need more than 25 inch Hg vacuum and you are using the pump indoor, consider using a oil-free/oilless pump. The later may be slightly pricer, but it is maintenance free and may save you money over the period of operation.

Q: I am running the pump at very high vacuum and noticed the pump getting too hot, what is going on here?

A: if the pump is properly lubricated and there is some air flow, it should not over heat.Lubrication is the key. The pump need a little air to bring the oil to the inside to lubricate the vanes. if your operation run the pump to an extreme vacuum where there is no air flow, and your system does not have a vacuum/control circuit to shut off the vacuum, the pump will loose lubrication and overheat. In this case, consider this: invest a little by adding a control switch, let the system shut off the pump when it reaches a vacuum level, say 28 in Hg. and automatic turn the pump on when the vacuum dropped to a level(say 24 in Hg). we do have one vacuum switch, available at: Vacuum Switch This switch can handle 15A circuit, if your pump is bigger, consider using a power relay with bigger current rating. continue running when it is over heated may damage the vanes, and void the warranty.

All our pumps come with a built-in thermal protector in the motor, this feature helps to protect the motor from over heating if that occur duing your operation.

Q: Silicone, Epoxy, composite or similar "Molding" or bagging Operation, how does it work and what size of pump should I use?

A: I received a lot of questions regarding this kind of operations and the pump selections, so instead of answering them again and again, I will pull some of the answers together here.

How it works? silicone/chocolate/concrete/Epoxy/gluing/boat/car body/airplane body repair or other molding/baggin/chamber operation(like surf board snow board, ski board, or even violin making) all these use a semi-liquid material to fill a gap between parts or inside a mold, when it is mixed, it will have micro air bubbles in the liquid part and between the liquid and the surfaces of parts or mold, these small air spaces reduce the electiveness of the "gluing" or make the products cosmetically unattractive. a vacuum casting is the easy answer. Under deep vacuum say 1% of atmospheric pressure (about 29.6 inch Hg), the micro air bubble will enlarge 100 times of its original size, the gravity will make them much lighter and escape from the liquid or semi-liquid gluing materials. In so doing to eliminate any air bubbles, micro or macro.

How it is applied? This varies a lot and depends on your operation, from a small vacuum chamber like a bell jar to a whole sheet of plastic covering a 3 X 6 ft counter top, to 16 X 10 ft poured concrete slab. If you have come to this far to read this, you are looking for a vacuum pump, you must have a system to apply the vacuum. This is a good link for the setup: https://www.youtube.com/watch?v=pRE90uu4CVw

what size of pump is good for my operation? This all depends on your size of operation and how the vacuum is applied, if there is a constant leak of vacuum, and the nature of your material, etc. Usually, smaller the chamber smaller the pump, leaking system may demand a much bigger vacuum pump. Faster curing material need a bigger vacuum pump than a slow curing concrete. One thing needs to keep in mind, the surface of the glue material always cure faster than the inside because of surface evaporation. You want a pump that pull to a deep vacuum fast enough to let the micro-air-bubble to enlarge under the vacuum to escape from the glue material before the surface cures. After the surface has cured(means sealed in this case), the glue material may still be soft, but any air will not be able to escape from it or entering it, at this time, running the pump continuously will NOT help, you may turn off the pump and let the part stay in the vacuum chamber for a few more ours if it is a fast curing glue or overnight if it is a slow curing concrete. Turning off the pump and release the air also give the chamber an higher pressure that make the molded part to cure to a higher density than at vacuum.

What pumps to choose from? Only 2 stage pumps are suggested for this kind of operations. These pump are tested by the market and recommended: VPD5(5.5 CFM), VPD8(7.5 CFM), VPD10(9.5 CFM), and VPD12(11.5 CFM) can be chosen depends on your size of operation. Adding a vacuum tank/reservoir will also help in speeding up the vacuum drawing. For this kind of operation, the general rule is, a bigger pump is alway better than a smaller one. But, on one occasion, one complained the glue burst in the mold, so you have to know the nature of the gluing materials as well.

Q: About Micron Rating, can your pump operate at this low vacuum?

A: the micron rating was done in the factory, and was verified by a third party.

one thing needs to be clear, though, the test was done in an IDEAL condition, that is: without any load to the pump, that is how they test the pump in the industry. in the real world situation, you want the pump do some thing with a load; often, with connections and a vacuum chamber. any micro-leak, or moisture or any liquid in the "system" will make the system not so IDEAL. Even the compressor oil is considered a liquid and will have vapor pressure which lower the vacuum level. In another word, any air pump will likely run at a not so "IDEAL" condition and will not be able to run at the rated micron. if you do need pumps for this low vacuum condition(50 micron or below), you might have to look for a molecular pumps for your job, not a oil-filled rotary vane pump. ALL I can promise you is this, every pump we carry was test-run for 2 hours before it was packed. these pumps will bring water to boil at room temperature if your system has no leak. this is good for most of my buyers, for HVAC jobs or most lab/workshop setups. if you do need 100 (or below) micron vacuum on your every day run, you might have to look some where else for the right pump.

Q:Gas Ballast Valve, What is it for?

A: All 2-stage pumps of model VPDx made by VIOT are shipped and contain a gas ballast valve. This is viewed as a brass adjustable knob (thumb operated) on top middle of the pump.

In HVAC evacuation jobs, the user will likely get moisture, or solvent vapor or other condensible contaminants as part of the gas stream and get trapped in the vacuum chamber/oil. These contaminants come over because they have turned into gas from a liquid under vacuum. They then travel to the pump and turn back to a liquid and mixed with in the pump oil. The gas ballast is a fine metering device connected to the second stage of the pump that allows a small amount of relatively dry, ambient air in to help prevent moisture vapor from condensing in the oil.

All liquid chemicals have a physical character known as vapor pressure. This vapor pressure is a function of physical chemistry law. The basic formulae is PV=nRT. I could get into an explanation more detailed here, but suffice to say that as a result of this formula, water will boil at room temperature when a vacuum pressure of roughly 29.3" mercury vacuum is achieved. When water boils it is turning from a liquid into a gas. All chemicals have this feature, just at varying temperatures and pressures based on their molecular construction.

It is possible to throughput some of these contaminants from your system and through the pump and that are where the gas ballast valve comes into play. If you do not require high vacuum less than say 300 micron for instance, then you can open up the gas ballast valve during the evacuation procedure and get some of these bad molecules out of the pump through the exhaust port of the pump. Remember also if they are coming out the exhaust they potentially are entering your workplace. This may pose a hazard either health based or fire based. If you are looking for better vacuum pressures, the valve is adjustable. This feature is not the total answer; it helps, but should not be considered the solution in problem applications with lots of contaminates.

If and once the pump is contaminated you can again use the gas ballast valve to assist in purging some of these contaminants from the vacuum pump oil in which it now resides. Close the pump inlet port off to full vacuum and allow pump to run/actuate with gas ballast valve in open position. This again will help purge the pump. Take a long lunch with the valve open. Care again should be considered to the exhaust stream. If the pump is "smoking" or exiting oil mist in good quantity, you may come in the next morning to a room full of oil mist. Piping the exhaust air to an exhaust hood or using a coalescing filter like a capture filters can help eliminate this problem area.

Purging the oil in the pump this way apply to ONLY liquid form contaminants and which is easy to be evaporated and cleaned out of the system. High boiling point liquid and solid contaminants like carbon deposit will never be purged out this way. Changing oil is the only way to clean out the later types of contaminants.

It is common during operation of the pump with the gas ballast open for there to be seen oil mist or "smoke" coming from the exhaust of the pump. This is common for rotary vane based vacuum pumps at these pressures. Use of Mist Eliminator or Capture filter may help in eliminating the "smoke" some how.

If you have no problem with contaminants you should use pump with the gas ballast valve closed. We consider this "normal operation".

Important Issues concerning deep vacuum pumps and HVAC & Refrigeration Service:

Moisture: Moisture within sealed refrigeration systems cause CFC, HCFC & HFC refrigerants to break down, forming hydrochloric and hydrofluoric acids. These acids will attack the hermetic motor winding insulation and ultimately result in compressor failure. Several variations of acid test kits are available to determine the presence of acid. Pulling a deep vacuum (500 microns or less) is the only method which assures you've "boiled" off and removed all moisture from a sealed system. And a system which will hold a deep vacuum, is also leak-free.

Measuring Deep Vacuum: Standard manifold gauge sets, with compound low side gauge, are inadequate in determining deep vacuum. They are just simply not accurate enough. The best method of determining you've properly dehydrated a system is with the use of a micron gauge. The alternative way of doing it is vacuum to the max and hold the vacuum, if the vacuum is holding at a high level(say 25 inch Hg), you are relative sure the moisture is eliminated.

Oil: It's the specially formulated, low vapor pressure vacuum pump oil that absorbs the moisture (water vapor) during the evacuation process, and this oil has a finite moisture capacity. This is why ALL vacuum pump manufacturers' instructions will state that it's important to change your pumps oil AFTER EVERY USE, if the pump is not supplied with ballast valve. You should be able to take your used vacuum pump oil to a local PepBoys, Jiffy Lube, etc. for recycling. Furthermore, the hygroscopic nature of polyester (POE) refrigeration oils contained in systems utilizing HFC refrigerants (R410A - aka Carrier's PuronTM), R404A, R134A, may require multiple vacuum pump oil changes to effectively dehydrate, especially if the system has been open to atmosphere for more than a brief moment.

If you need vacuum pump oil, we recommend your local HVAC Contract Supplier to avoid shipping cost. We do have small bottles of vacuum pump oil if you can not find your local supply.

Evacuation Rates & the "CFM Wars": It's true! The capacity of a standard 1/4"ID hose is limited to 3/4 (0.75) CFM. And that's ONLY if you remove the valve core depressors from your hose ends AND Schrader valve cores from the system's high and low side access valves(that is unlikely!). Thus, evacuating from both high and low sides, you'll max out at approximately 1.5CFM. Standard 1/4" charging hoses are also not designed for vacuum applications. Therefore, please consider our manifold gauge set with 3/8" Combination Charging/Vacuum Hoses (GM410V4). The bigger and shorter hose will short the evacuation time by more than half.

Q:More Questions on milking machine hookups:

A: The following solutions are related to the pulsator/milking, make sure to read it all if you are using the ump for milking:

Q:What pumps are recommended?

A: Oil-less vacuum pumps are the best choice for Milking. If you are milking in a open area, single stage pumps can be used if the oil mist does not bother you. For small farm single milking station operations, a 3 CFM is enough for goat milking, 6 CFM may provide enough power for single cow milk station. VPDS3 will do a cow or a goat at a time fine. VPDS6 will handle all small farm milking operations. VPDS12 is the biggest pump we have for milking. it can handle 2 milking stations.

Q:Is air regulator required?

A: If you operate a commercial milk farm, you will need to set up the operation more reliable and invest in all the elements: vacuum tanks, all the control valves, air flow regulator, pressure regulator, pressure gauge, etc. For a small farm, vacuum regulator is highly recommended so that you will not hurt the animal, Vacuum gauge in line will help you to know what level of vacuum the system is running. If you do have a regulator, and your system is running slow, adjust the vacuum to a higher level, but not to exceed 15 inch Hg.

Q:Oil mist and oil "leak" problem in the pump?

A: Not all men or women are trained to be engineers, but learning will help to prevent the engineering problems in the pump hookup. If there is an oil problem, check for these:

1:Is all and every connection air tight?

2: If there is an air pressure regulator in line? make sure it is calibrated and set to 12 inch Hg at the teat-cup level(NOTE: for milking, not at the pump level, which may be 13 to 18 inches Hg depends on the length of the vacuum hose line), setting it higher will cut the void air flow through the the regulator.

3: Make sure the tubing get to the pump through a Barbed tubing connector, do not push the tubing to the threaded flare intake port, it will create an air leak right there at the pump.

Cut the void air flow, less oil will be blown out through the muffler. Remember, there are expensive mufflers available on the market for eliminating the oil mist. if you have checked all of the above 3 reasons, and could not solve the problem, install an expensive muffler. Or consider using long hose to conduct the exhaust air out of the working area or outdoor, by adding an adapter to the pump exhaust port and extend it upward and toward outdoor space. most of the the oil mist in the hose will be condensed and return to the pump. No muffler is needed in this case if you choose to use long hose.



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