Has anyone used a water chiller on a roto?

Would this water chiller be sufficient in chilling a 5L roto?


Yes i have 2 that ive used on a 20l you will probably want a cold trap but mine also doesnt go that cold so you might be good. Assuming it holds near that temp and depending on the size roto your trying to use it on

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5l roto I’ve used the 5gal bucket plus a pond pump, tap water theu a hose, and a dbsl chiller.
My tap worked just as fast as the chiller. The chiller was barely able to keep cold enough. I put a fan blowing into the chiller canto help move heat away. Chiller was used in a 82* ambient room temp. Same with tap, and 5 gal bucket way.

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Depends how hard you suck…

If you DONT suck, you can condense your ethanol with 40C water!

If you pull down to 2um, even -80C won’t solve it.

(I posted a table around here somewhere that shows ethanol’s bp at various vac levels. Not gonna go looking for it).

By adjusting your bath temp and vac level, you can make almost any condenser temp work.

Edit: and then I have to ask ; why are you calling this a “water chiller”? At -30C water is not gonna be particularly easy to push through that condenser. It’s a chiller. An air cooled one. (It’s using a fan not a water hookup to dump the heat. ). You’ll be running a glycol mix.


Honestly I didnt see anything pointing towards other fluids, and water was in the titled. Ive never used a chiller and have only used water aspirators but this chiller seemed like a good deal for what it was. But yea -30 is quite cold for water lol… :man_facepalming:… 5L chiller tank seemed a bit small. Both are order, cant wait to give it a shot. if not 80l water aspiratoring and a hell of alot of ice here i come!

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I read this totally wrong but it got me thinking

Can you use a rotovap as a freeze drier if the water bath was cold?


Water aspirators are pretty lousy for pulling vac and the water in them gets really hot (which makes for worse vacuum levels) without a constant influx of ice as you’re already aware I’m sure.

IMO most if not all import rotovap chillers are significantly under-rated for the duty many of us put them thru, if your lab is air conditioned and kept under 70*F you might not have a problem, but if its 80 or god forbid 90+ you’ll see performance drop off sharply. Best bet is getting a roto chiller that’s sized for at least the next size up of rotovap, or better yet 2-3 sizes up.

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Lol when the wiped film room is 100 f but u need all the heat transfer u can get :laughing::rofl:


Totally can. I forget which post it’s in, but someone did exactly that. They put dry ice into the bath and lyophilized some fresh frozen that had thawed and re-frozen a couple of times. He had good results also. I totally forget whom it was. Hopefully they’ll see this and mention something!


What would be the reasoning of my chiller not actually chilling? Have it set on cold/cycle, and stays the same temperature. Ran it for like 1-2 hours and if anything it went up a hair, My workplace was hot today but not even flinch the temperature??? Theres gotta be something im doing wrong or is wrong! help my first chiller…

What type of fluid are you using?

E Glycol and water 50/50

Probably needs charged, look to see if you can find a leak at a soldered joint. Bought new or used?

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I’ve found running a roto with less vacuum and higher heat performs better.

Chillers are more powerful the less they have to chill the fluid going through them.

Brand new, never used.

Prolly doa then @PrimO.Oil contact who u bought it from

If your using glycol, don’t go too low on temp.
Just set it @ -6c and your roto bath at 50c. Set your pump regulator @100 and work your way down on vac from there as you see fit. )If your using ethanol)

Where did you buy your glycol from and how are you liking this chiller? I’m thinking about ordering one myself but haven’t decided yet.

Our company is selling chillers, what size do you need?Maybe I can help you.

Two weeks ago his chiller was not getting cold. I’d personally avoid import chillers for lack quality in after-sales service. You really don’t need too cold of a temp for your condenser if you’re dialing in the right parameters, as others in this thread have implied. Especially for a 5L/benchtop Roto.