CMEP-OL Refrigerant Recovery Pump

Our pump just went in for regular pm maintenance and upon return it is louder. We run this pump for low sound output. The pump is louder and seems to be labored but is still functioning. Does this just sound like normal wear and tare or is the loudness and the labored sound a sign of other problems not seen at it’s maintenance check up? Anyone use this pump?

Who did you have do the maintenance and at what interval? What revision CMEP is it and what if any mods have you done to it?

Your post is very lacking on details that would help us help you in any meaningful capacity

My former Santa Cruz city bus came with a two speed transmission: slower & louder :wink:

I’ve had three of those pumps, not one of them came properly assembled. One wandered away with a former partner, one still needs proper pre-operation assembly. the other needs a rebuild.

They would last longer if they had a wrist-pin and separate connecting rod. The one piece pistons they use wobble, and will eventually wear the cylinder walls into your extract.

I’ve got pictures somewhere of what that actually means. if @BigWorm760 comes back and gives more details, I might even post them…

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So Cmep-ol are no bueno. Give it to me straight Cyclopath! :wink:

They are better than the other’s I’ve used, the Appion & the CPS.

I considered solving the problem myself after tearing the first one down. There is a better option, but I don’t have that information stored for some reason.

perhaps because I’d rather do hydrocarbons passive after seeing the insides of the pump.


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Any thoughts or advice on master vapor?

I like these. They are pretty clean, only downside is the screw compressor! You need a 10k compressor to run your 3k pump! Not to mention the miles of air mantafolds and dryers plumbed everywhere!

yep. that’s the critter.

Damn, $10k? That’s not looking real hard. Picked up a low hour 25 HP IR rotary screw that would have no problem running a couple of Haskels for $2500 off of Craigslist.

I’d like to think a brand new screw compressor would be nice and super reliable but my real world experience says that they aren’t and that nobody staffs enough techs and keeps enough parts on the shelf to deal with the problems that happen when they outsource their production to a place that doesn’t give a shit about quality control.

His is what it cost, 10k was a slight exageration…but not much
The air dryer is about 1/3 the cost of the compressor.

That’s why it helps to have a tig welder and machine tools. If we can’t get it, we make it!


Can confirm. Between my Miller Dynasty 300, Lagun CNC and 17x40" lathe I get shit done.


We currently have some units that each run with two master vapors. Master vapor is great but it really really really doesn’t like pumping against positive pressure, especially if you’re trying to recover down to a deep vacuum on the inlet side. Keep the pressure in your recovery tank under 20psi, preferably under 15psi for best results. I recommend for use with butane only unless you have one hell of a powerful chiller.


here is my first CMEP-OL sounded like before I tore it down for a rebuild: you might want to turn your sound down…

and here is what the piston heads looked like


the black stuff is presumably the cylinder walls…


Ohhh nummy!

The black stuff is grease slung from the bearings ive rebuilt quite a few but im no pro.

If its loud all the time it might need bearings. Gets loud on and off get a crankcase vent