Quadrafire Santa Fe staying running issue

[larry1271]

I just bought a 2018 Santa Fe, person who owned it appears to have taken great care of it, very clean and no abnormal noises. I did a test fire in my garage with a jumper wire instead of a thermostat. It started up good, ignite pellets, room blower came on so I figured I was good. Shut the stove down. I did a second test fire, same start up however after about 10 minutes after startup, it stopped feeding pellet and the stove shut down. I attached the thermostat to it and same thing. I took the side cover off to view the lights in the control box. After startup, the green light came on, great fire, feeding pellets, red light came on, still feeding pellets, then the green light came back on and it shut itself down again. I checked the thermocouple and it seemed the wire wasn't all the way in the ceramic piece. Started it again and same thing, I did mess with the switch on the back, moving it from high to low and it started feeding pellets again, put it back to high and it stopped after a while. I gave up after this to take a break. Anyone think its the TC or control box or something? Thanks for any input