Can't get solvent to pass through

Hi Everyone! Got through my first run with my new CLS. For some reason I can’t seem to get the solvent to come through into the collection basin. I can pull a vac and then let my solvent run but only a small amount actually goes in then it stops. Why is it stalling? Even if I open the ball valve and let it run through without soaking seems like only gas goes through Not liquid. I’m cooling my solvent tank.

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From the text book of @cyclopath please give us a couple thousand words. AKA a few pictures.


Is the solvent flooding into your material column but not dripping into the collection base or is it stuck in the solvent tank itself? Either way it sounds like your pressure is equalizing and stalling things out. You need to add more pressure to the part that you want to drain. Look up hot vapor loop or nitrogen assist

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the butane leaves the higher pressure/temperature zones and goes to the lowest pressure or coldest zone.

you need to chill your collection slightly, or pressurize the material column.

if you’re chilling the tank and expecting the butane to leave without a pump you will be disappointed.


Where are you pulling vacuum?

You need to create positive pressure (above atmospheric) and push through to the collection vessel. If you’re creating vacuum you can move solvent from point A to point B, but with a low BP solvent like butane it will never remain liquid.

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Are you cooling your solvent tank? If so with what?
Do you have a separate solvent tank for recovery?

The butane moves via pressure, not gravity. You solvent tank has pressure (maybe) and your system has vacuum, so the solvent will get sucked into the system. It will stop getting sucked in when the pressure in the system reaches the same pressure as your solvent tank (pressure equilibrium). This will happen very fast because you are putting the same pressurized gas into the system.
Once this happens, you have a few options (the plan is to lower the pressure in your system and keep the flow of liquid solvent coming through);

You can try putting your collection pot into something very very cold. This will draw the pressurized gas into and slowly condense it.

You can get a separate solvent tank and pull a vacuum on it (or get it very very cold). Then hook it up to your collection pot, and open the valves. It will suck pressure from your system into it. I recommend the very very cold part (dry ice is best).

You can get a refrigerant recovery pump, put that between your collection pot and your recovery tank. It will suck the pressurized gas through, condense it, and return it to your tank.

You can use nitrogen or warm butane gas to PUSH the solvent through your system. You would hook the push gas up to either your solvent tank or the top of your material tube (depending on where/when you stall), then open the valve to push the solvent down. This concept doesn’t lower your system pressure, but raises the pressure of your solvent input.

Generally, a combination of these techniques works the best.

You’ll likely need more specific guidance to actually use these techniques, but I hope this helps you understand what’s wrong and how to fix it. Hope this helps.


If you don’t have dry ice, you can get fairly cold with just salt, ice, and water. It won’t be cold enough to pull the best quality you possibly can, but you’ll get cold enough to get a really good product in the end.

I run passively like this, the above comments are very detailed and should get you on the right path.

My process is like this

  1. put solvent tank and collection base in cold salt ice water bath. My tank only has enough gas for a run (2lbs) so I always use all my gas. If you don’t use it all per run, you’ll want a scale so you know how much you’re injecting.
  2. pull vacuum on entire system with material loaded, no gas in the system. At this point my column and collection are at -29hg. My solvent tank is sitting in ice water. Let sit for about an hour to get down to temp.
  3. pull vac on the system again to remove any residual moisture. (this point seems pointless as I’m still at full vac but I do it anyway)
  4. hook my solvent tank from the vapor port to the top of the material column
  5. suspend the solvent tank from the ceiling using secure brackets and straps upside down so it lets solvent drain from solvent tank through vapor port until everything has drained. At this time the solvent has made it into the collection pot that’s still sitting in the ice water. (butane will follow the cold)… If you do this, please be very careful. If you drop a tank full of solvent, it can be very dangerous. I only do this with a manual pulley system I designed, with the tank securely strapped onto it.
  6. remove collection base from cold water bath and let it warm up at room temp for like 10-15 mins
  7. Place recovery tank in the ice water bath. (I recover into my injection tank when I’m done, so I do this to help remove any pressure from the tank. It will be around 2-5psi from residual vapors, but recovers just fine)
  8. Hook up all your lines for recovery, place collection base in warm water bath (~80-90F)
  9. begin recovery. (I recover into my liquid port. @Killa12345 had recommended this a few times, it works well by forcing the vapors to the bottom of the tank, which will force them to go through the cold liquid butane, which will help recovery not stall vs if you recover into the vapor port.
  10. Once you recovery is where you want it, you can transfer your extract for final purging/polishing

$20 says he had hot water running in his collection


Thanks all. No I had cold ice water not hot water on my collection.

I have gotten the hang of it now with 6 runs and all have gone well.

Thank you!!