Hi,
Thanks everyone for the advice!
I haven't used it for a while and I just had my son help move it into my slightly warmer garage to look things over. With a foot of snow coming, it seems like a wiser decision.
I popped the side panel and found some old pellets that got wet. They accumulated in the area where the electric cord comes in to the box and splits into three separate wires.
I believe this is the culprit.
I think in the frozen temperature, it works for a bit, but electricity passes through there it was starting to melt some of the piled up moistened / frozen pellets, causing it to trip.
I'm moving it to the garage where it can warm up some. Vacuum out those pellets and let her get dry as a bone, and with a tiny bit of luck, we'll be operating again.
Thanks again!