Robinair (15600) CoolTech Vacuum Pump - 2-Stage, 6 CFM

Needed a vacuum pump for stabilizing knife/tool handle blanks out of porous lumber. It does its job, leaving it on overnight....no problem. This thing is quiet and keeps a steady vacuum in my chamber until the lumber quits yielding air, at which time I let the vacuum off, and this allows the resin to rush in.

I have always respected Robinair for their A/C equipment and have this 15600 pump along with their Manifold Guage Set, RG6 Reclaiming Machine, 134a Refrigerant Identifier, TIF Weighing Scale, and many fittings. I strongly recommend the 15600 Deep Vacuum Pump for automobile/Truck A/C systems. If taken care of properly this pump will last many, many years. It's very important to use the Robinair Premium High Vacuum Pump Oil which will ensure that the seal can be made to consistently result in vacuum of 15 microns. Please Note: All oil is hydroscopic, the oil will hold moisture from the evacuation of the system. Learn to use the Gas Ballast function to minimize the contamination of the pump oil by water. This oil/water combo will make Hydrofluoric acid which will etch the two-stage elliptical chamber where the vacuum is created. Failure to change out the oil after EACH USE and re-fill with fresh oil will result in permanent damage to the pump where you will never again achieve this low pull to 15 microns. Follow the pump instructions carefully when you put oil into it. That means specifically DO NOT fill to the center sight glass line initially! Fill the reservoir to the BOTTOM of the sight glass only. Run the pump for a few minutes and the oil level will rise closer to the center line as it heats up and expands. Then add small amount of oil to the center line while the pump is running. DO NOT OVER or UNDERFILL! The pump is now ready to use but we will check the pump vacuum FIRST. If the pump cannot hold a vacuum then you have to get that remedied first! If the vacuum pump cannot pull a 15 micron vacuum within 5 minutes then there is a problem. The three nipple manifold has plastic caps with seals inside them. These seals will leak at a high vacuum and must be treated with a small amount of Nylog Blue following the instructions for a thin coating each side of the rubber cap gaskets. I use a Thermal Engineering Electronic Thermister Vacuum Guage with its sensor mounted on 1/4 manifold fitting: Appion P/N VFL45L -- Double Sided 1/4" Flare 45 degree Connector. The vacuum guage sensor must be ABOVE the pump at all times to prevent oil contamination and permanent failure from spit back when the pump is shut down. Close the Iso-Valve that isolates the pump from your maniold guage set. Start the pump and let it pull down to 15 microns as indicated by your thermister vacuum guage. Shut off the pump and observe that the vacuum is holding after several minutes. Please Note: It is virtually impossible to know the vacuum unless you have a electronic micron guage! The manifold guage set will not do it! This is a very high quality vacuum pump. Reading the instructions and following them will ensure that it will operate to its design spec for many years to come. Mike - ASE Master Automobile Tech & ASE Master Medium/Heavy Truck Tech

So I'll start by stating I first ordered the red Robinair 15800 vacuum pump and returned it to order this unit. When you see reviews stating go with the Robinair blue units because they are better quality, better built, I should have just went with this one. Well the Red 15800 one was a pitiful quality but since I'm not reviewing that one, I will state what I have experienced so far with this one in comparison. I do use this with a cow milking machine. This unit is less noisy than the red 15800. I like that the exhaust blows out the handle, and not straight up and sometimes in your face if you fiddle with pressure gauge and other things. Now because I don't move the vacuum pump, it sits in one place all the time, there is a spray trail of oil and whatever else comes/spits out of that exhaust all on the concrete so that is a negative to me -- the other red unit sprayed it on the wood walls of the stalls so that was worse to me. I've had a few cold mornings and it seems to take a second to warm up and really power up, sometimes with a sputter. It's a good thing I'm not up north in a real cold area as I just don't know if it would work reliably. I do wrap a blanket around the unit thinking it might help it not struggle to run or rather not run in the cold...not sure if it makes a difference. Now for the 3 point connection, I did prefer the set up on the red version just because the size of the pipes I use with milking set up was 3/8 and the top piece on this 15600 one is 1/2 so I had to pick up a reducer or angled connection. If someone is looking at this for a set up like mine, you can easily run 1 milker but I don't think you could run 2 milkers off one unit but maybe could have with the red unit. At this point, I haven't had a major oil leak like I did with the Red 15800 -- the oil drain plug just leaked without me ever touching it in the first month.

I have used this pump twice so far, and it works very well. Pulls the system down very quickly due to the large displacement, so it doesn't have to work hard to get the job done. I am using it for automotive ac and that required a different fitting than the one that came on it, also found that on Amazon. The pump comes with a bottle of oil, I did not know this and ordered a bottle of oil, still not a bad idea as you should change the oil often for best performance.This pump is still serving me well and running strong!

This pump is every bit as good as advertised. I have used Robinair vacuum pumps off and on for many years and this one is as good as any before it and better than some other brands I have tried. Great value for a superior product. I especially like the Iso-Valve which isolates the system being vacuumed so you get an accurate reading on the gauge without having to restart the pump. I would recommend this unit to any technician that is looking for a medium capacity highly portable pump that will evacuate quickly and effectively.