I forgot to turn on the cooler on my dynasty 200... While running a couple welds on some thicker aluminum 3/8, Apparently it makes a lot of smoke/steam when the water cooled line overheats, and ruptures! Don't know why they don't make it plug into the back of the TIG so it comes on at the same time!
I've done it. Also got lucky many times too and only felt the torch get warm before realizing I forgot to turn the cooler on. Also was using a dynasty 200dx. I am with you in thinking it should plug in to the machine but being a dual voltage machine there are issues in complying with UL or some such BS. All I know is its wAy too easy to forget to turn on the cooler. Especially if your cooler is kinda loud like mine and you leave it off for a few tack welds and then go ahead and weld with it off.
Seen a few blow out from corrosion in water lines too. On some sync 250 units piped into tap water that just drained.