Recovery pumps (running 2 or more simultaneously)

Just looking for some advice on safely running more than one recovery pump (CMEP OL)for butane. Im planning to vac from the same vessel into 2 different condensing coils that push liquid into the same recovery vessel (different ports).

Im curious as to thread size ratios recommended for maximum efficiency. Should i be going from say vac side 1/2 inch into a 3/8 for compression? Or 1/2 to 1/2?

Im looking for any other tips or potential hazards to watch for. For example im pretty sure the compression sides need check valves to prevent back flow.

We use 3/8 hard line and compression fittings on our extractors, make sure you don’t over tighten them. The pumps should “check” the lines . Just make sure to put a ball valve on each part of the system so it is isolatable. A pressure relief and a pressure Guage would also be nice for any part of the system that can be sequestered off.

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If you already have the pumps I probably won’t stop you but if you haven’t yet bought them I’d do everything in my power to avoid the CMEP OL pumps, they are absolute garbage, like to wear out quickly, bearings are shit, they aren’t actually oilless and you will end up getting bearing garbage and hydrocarbons from those bearings in your butane stream without making some extensive modifications to the pumps, and even then you might still.


6 cmep’s are better than having one master vapor pump that doesnt work at all. I got a bunk mvp and decided to get something more disposable. Thanks for the info though!

dang a bunk mvp? I’ve had two and just my first one has lived the life of 100 cmeps…

I heard a story on reddit where a company got one, it broke the next day. After having a new unit sent out they experienced mechanical failure again. I heard even the third one died after a few days. Either people are doing something wrong and suckling liquid through them or there is a manufacturing issue with a certain lot. From others I’ve heard great things about the mvp.:thinking:

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My co2 inlet was glued shut by a pine smelling resin. Customer service blamed me… Lame

Were you pulling liquid hash thought it? We mount our pumps up high, like 3 feet over the collection base.

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No lol it came like that

Was it bunk if you killed it with slugs of liquid?

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It was bunk. The problem existed on the co2 inlet and not the solvent side. I definitely didnt get hash in it i have a large desicant/manifold which acts as a reflux.

Interesting. I’ve had two, probably about 3-4 months apart? Both work fucking great. One running just butane, the other running just propane. ZERO complaints

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Using multiple recovery pumps is great. I would definitely recommend using two or even more as long as your evaporator can supply enough vapor for them to pump.

The unit I currently run has two master vapor pumps, and a rack of 6"x48" jacketed tubes. It’s awesome, we can fill up four of the tubes at once, dump them all out, and redirect one pump to recover the tubes down to vacuum for replacement separately while bulk liquid solvent is recovered with the other.

If you’re using more than one pump, I’d recommend using multiple coils if that’s what you’re using. If you are using something like BHOGART’s extra large heat exchanger, then you could easily direct them all to that one large one.

Stepping up your lines to half inch on the inlet side couldn’t hurt if that line is shared between the two pumps, as it would get you more potential CFM flowing to the pumps. If the outlet side is going to two separate coils I’d say 3/8" is still fine.


I ran 4 cmepol together coming from one manifold with 1/2 inch lines that then split into 3/8 going into each pump, each pump has its own heat exchanger. I noticed that it was better to have 1 line that split then to have multiple ports out of the manifold there would always be 1pump that was starving for vapor. With 2 I hit 1lb every 65 seconds running no dry ice.


How hot is your water bath for evaporation? Im running them seperately out of the manifold. Im wondering if I can prevent the “pump starving” issue with more gas flowing.

Depends on what your running,I’m 90%crude so I just use bucket heaters they get about 115 or so. I also have about 80lbs of gas out in the system at all times in various recovery pots all tied into 1 manifold

I dont think the pumps mind if youre making crude or lavender oil.

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But your oil minds the temperature that you use you don’t want to run that hot if your going for nice shatter or etc.

Were you using the small exchangers ($1000) from bhogart per pump? I just got my 2nd cmep and was going to just tee them off before my single exchanger… now im wondering if I should change up my plan and just buy another… Def want to figure that out sooner than later because I was going to mount mine onto of my 30 gallon tank but once its mounted its fuckin on there unless I completely empty the tank… Also, were you running the ice water opposite of the flow of the gas? I see on their manual you must do that

I had my pumps in the top of a metro rack and the exchangers below it and tank below that so everything could gravity drain and there was no restrictions or sharp bends. I never liked the mounted to tank exchanger for one reason as you mentioned and it makes a very sharp turn. Mine exchangers were t’d off one garden hose running from a sump pump I believe it was in the top out the bottom but not sure