From my experience with 6x Chinese 50L rotos:
- Ditch the water bath vacuum, if you’re using the roto for more than an hour the water gets hot and vacuum level fades. A well worn Welch or cheap Harbor Freight vacuum pump will pull deeper vacuum than the water bath will
- When you get sick of the water bath and use a real pump, put a good vacuum trap in line and size your pump for more demand than you think you will. If you pick up a second roto (or more) you can run them all off a single vacuum source.
- They don’t like to be run on the low end of the voltage spectrum. If it says its rated for 220 volt operation it will run great on 240, if you try and run on 208 you will have random electrical hiccups on the roto itself and the chillers will overheat and not keep up
- The Chinese chillers are hot garbage on their best day. If you don’t have the electrical service you could always set up an IBC tote and an aquarium powerhead style pump and recirculate, or set up a garden hose adapter and do a “total loss” coolant where the outgoing water goes into the drain or waters your lawn. If I had a do-over I’d just buy the roto bodies and glass and use a Chill-King with a multiple tap manifold or individual higher quality chillers (like Neslab).
- If you’re buying new, the glass will come internally packed with sawdust. If you don’t have a good sized air compressor to blow the sawdust out, make friends with someone who does. Wear a respirator doing this lord only knows what kind of toxic shit is in that sawdust.
- If you extract cold you won’t have a bunch of nastiness cooking to the inside of your evaporation flask. Handling glass frequently and cleaning it sucks. I haven’t broken any glass but I’m sure its a nightmare to get a replacement flask if yours gets cracked.
- Figure out a slurp tank and hose to empty your roto globes without pulling the glass, you can thank me later.