Just bought a new series 5 from TS. I assembled it and went through the burn in process. I wanted to see how it ran at 400 so turned it up. Display shows between 400-410 and runs for about 10 minutes then display starts fading and the grill shuts off completely. I turn back on and go through shut down procedure and try again with same result. Only thing I can think is there's not enough heat shield and display is getting hot enough it fail safe shuts down?