It is a vacuum pump, Leybold D12. I get the idea that a new one ought to pull 8 millitorr or so. I reckon I might be getting about 20 torr.
Most hardware stores (at least in the U.S.) have clear plastic tubing. Connect one end to the pump and place the other end in the mercury (with the tube vertical of course). Crude, but it should give you a good indication of the pump's operation.I'm guessing by 1 ) what the arc from a neon sign transformer looks like, not much different from atmosphere, but with small bright glow areas on the electrodes, and 2) what I would expect if the pump was full of water, which it could well be.
I have a thermocouple head, but the pressure is too high to get anything out of it, 2 torr reads as atmosphere. If only I could find a few centimetres of glass tubing, I have mercury.....
A decent pump should actually be able to cause water to freeze.
I don't see how it could cause water to freeze at room temperature. Deceasing the pressure, both decreases the boiling point and increases the freezing point but the maximum freezing point of water is around 4°C where it has no liquid phase at low pressures.