Lite On Laars Lite 2 Heaters: 250,000BTU MV Heater "heater shuts 15 min even" Questions

...even if it is not calling for heat. Auto only runs when calling for heat. Does the fan turn off in the auto mode at all? To test it...BE SURE THE FAN IS IN THE AUTO MODE ON THE T-STAT... Turn the ...

...15 mins. Sometimes it?ll work until it gets cold again a few weeks later. Could the outside temperature affect gas flow? or Does the furnace working overtime because of the low temps cause something ...