RV Repair: suburban SF-25F furnace, hot water heater, sail sail

Question
Until recently my furnace worked great. I ran out of LP and filled up my tank connected it back and when i turned the furnace on the blower came on but never got hot I have tried several times with the same result. My hot water heater works so i believe that means the gas is getting through the regulator but I do not know much about campers. Any advice would be appreciated as I do not feel confident enough to pull the furnace out to take it to a repair shop.

Answer
Hi Jennifer,
Turn on your thermostat and set the temp to it's highest setting. Then go out and listen closely to the furnace running. It should came on, then after 20 seconds or so , you should hear a click and the ignitor trying to light the flame. If you do not hear that, you have a bad limit switch or sail sail switch. If you do hear the light cycle ok then there is a LP flow problem.