Try turning the furnace off and on at the thermostat a few times. If it is the gas lines needing to be purged, that should take care of the problem. Try using the trouble shooting guide from this site:
http://docs.renegaderv.com/Suburban/Furnaces/FURNACE_Service%20and%20Training%20Manual%2011-05-2015.pdf
Use the flowchart to diagnose your problem. When you start the furnace, look through the sightglass into the flame chamber and watch what happens. If the pilot ignites the gas, it stays on for a few seconds, goes off, relights, stays on and then goes out. Chances are the circuit board may need to be replaced. My brand new furnace did this, a new board installed under warranty cured the problem.
Bob & Dawn Married 34 years
2017 Viking 17RD
2011 Ford F150 3.5L Ecoboost 420 lb/ft
Retired