The water distillation unit is provided with a valve where chlorine and other volatile substances are ejected in gaseous form. Should one attempt to distill alcohol the alcohol fumes would escape out into the atmosphere from this valve.

Alcohol fumes mixed with air are extremely dangerous and can be ignited by a spark from a switch or a thermostat. Dangerous accidents could occur. This valve cannot be removed or blocked up. Irrelevant anyway, as the distillation unit has no problems distilling water, as water has a boiling point of 100C and is easy to cool down.

Alcohol however, boils at 78C and required much more cooling.
The fan cooling system has too low a capacity for alcohol so the fumes
pass right through the cooler, comes out and is mixed with air, a
dangerous mixture that can be ignited by the smallest spark.

There is a factory rebuilt alcohol and water still - The EasyStill - that is rebuilt with better cooling, chlorine valve taken of, higher separation etc. The EasyStill can also distill water but because of the higher separation (better purification) it takes longer time.

The EasyStill is located at EasyStill.com.

The EasyStill is the original and there is a bunch of copy cats that also sell a still that looks the same. But as far as I know there is no one of those that are just as good. They are just there to use the goodwill of EasyStill and sell another still that looks the same.