I don't think it'll be that easy to stop abuse from happening, only to mitigate the impact by deleting the machine when it gets too much.
As for the machine itself, it would probably be better if the ambient temperature would be more noticeable besides scorching/freezing. Air alarms can be set between 10-30°C by anyone iirc, and no one will notice it unless they check their PDAs air analyzer. Give people a character option for the comfortable temperature range, so they get notified if it's above/below it, without affecting the dangerous ranges. Give characters a default based on species (so as example drasks very low, tajaran low, human average, unathi high), and that allows cold rooms to be noticeable without snow laying around.
Also, it may be less prone to abuse if making snow requires you to have the room cooled down before being able to get it placed, maybe it could just be made that if you have a room below the freezing point, throwing(splashing) a beaker with hot water to make snow. Usually requires colder temperatures for such quick snow creations, but that doesn't matter for this.