Coleman DGAT075BDD Won't stay running

[nascarchic]

My Mom has a Coleman furnace in her Mobile home and it won't stay running.
We have checked the intake and exhaust..turned the thermostat off and back on.. and have had several furnace repair men out to check it and they can't figure out the problem.
It runs off of LP and we also cleaned all the snow away from the LP tank outside to see it that would help. Nothing has changed.
It kicks in and runs but shuts off after about 2 minutes. Sometimes it will not kick in at all and she has to hit the reset button to get it to start again. We are averaging about 15-20 degrees for the air temperature at night and she has to keep getting up to hit the reset button at night to try and keep the temp up.
Is it possible that it is the thermostat that is causing all these problems or should we be looking at something else?
Any help would be greatly appreciated!!!

[Greg]

I'm far from an expert, but I would look at a limit switch problem a bad limit switch could be telling the furnace it is overheating and shutting it down.

Greg

[Mark]

When you say 'reset' button, do you mean the limit switch with the button in the middle?

Mark

[nascarchic]

I apologize.. I am not sure what the "correct" term for the button/switch is. It is a small black button that is located right above the control panel.