I just hooked up my new PP256. Got 240v running to machine, a fresh bottle of argon (with about 5L/min), hooked up the garden hose cooling method and gave it a run. It was doing fine for the first hour or so of very intermittent use as I experimented with the dials. I have the foot pedal hooked up with 2T selected.

I was having a lot spitting and sizzling when adding 4043 rod. The arc ran clean without rod, so I figure the rod must be contaminated? Ran it through scotchbrite with no change there.

Anyway, after a break I came back to the unit and was just going to run some lines without rod. Working on .125 Aluminum (not sure the type). With the amps set at 125 I started into it slowly bringing the foot pedal in and after about 10 second, before reaching full amps the unit cycled off. The overheat light illuminated. I let it run for a few minutes and the light never went out. Restarted it and it did the same at a similar point.

Disconnected the foot pedal and tried it with the the torch switch and 2T and it kicked off again before it reached working amps, which I had lowered to around 90ish.

Any thoughts?