Be sure the TH switch is ON and temp set to high, Propane is mandatory (try your stove). Be sure not to block any discharge vents and return air. If it run before for some reason the sail switch might have been tripped. Don't know if you have an outside access door (easy for servicing) or if you can read the fault codes from the inside.
The RV furnaces are simple but have safety built in just like a home furnace.
2014 Ram 1500 CrewCab 4x4 5.7 Hemi 3.92 Rear and Air Lift 1000
2005 Jayco Jay Feather LGT - 29Y GVWR-6500 lbs.
Pro Series 1200 lbs. WDH with Double Sway Bar.
Champion 3100/2800 watt Inverter/Generator-Onboard Solar Power
ALJO 'Forever Young @ Heart' provide on their travels Music Entertainment to Senior Care Homes