You can look for a device like the one in the photo and reset it, these are located on the burner rack, let me know, other than that it will be the high limit switch which does not have a reset.
Ive reset the limit switch.. didnt seem to be popped,,, and it does it within 2 hrs of running,,,,,,the system is new just put in about 3 weeks ago..... where is the high temp one located............ your pic didnt come thru.... my email is XXXXX@XXXXXX.XXX
There is a picture of a high limit switch it inserts into the heat exchanger, but if the furnace runs on a startup and then shuts off on high limit then it won't be the other one I posted, it will be this one. These are suppose to reset when they cool down, does that happen ?
If you can't see th pictures tr to get to this web page,
It is either overheating or its defective, more than likely its defective.