Can I add in a couple of things to what Chill said?
While it's generally accepted practice that you should never leave your still unattended, I also use timers for my stripping runs to allow me do other work which may involve me going into the house for short periods and If you're going to process your stripping runs using timers you should;
1. Try to get your wash as clear as possible to prevent puking because the lid of the airstill can get blown off by an explosive surge boil or puke. Clear like this will completely prevent puking.

2. Place your Airstill in a large basin or plastic box to contain any spillage if the lid does come off.
3. Make sure the circuit your Airstill is plugged into has a cut off or trip switch in case liquid from a puke contacts the electrical connections.
4. Always use Distillers Conditioner in stripping runs
I know all these things are routine to experienced Airstillers but maybe not so obvious to new members of our illustrious craft.
AM
