linzatx, welcome to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences. Usually, the heating system and most of the time that will be gas furnace is inter-connected with the air conditioner. It could be a remote control or fixed to the wall t'stat. You will need to set it to the correct mode for heating and set the desired temperature. Make sure the LP gas is turned on and that you have plenty of it. Turn on the heat. If it does not start producing heat in a couple of minutes or shuts off, turn the furnace off and back on at the thermo tat. You may have to do this several times if all of the lines need purging. Once you get fuel to the furnace it should ignite and be fine from this point. If you are not going to be connected to shore power or have the generator running, be mindful that the furnace will draw a far amount of power from the battery bank. If your bank is smaller it could deplete it over night so recharge the batteries first thing in the morning. You can also run the furnace while traveling if need be; the gas must be on at the main tank.
If you have an LP leak detector that has an auto shut off, in the event of a leak, it must be turned on to get LP gas to flow. Good luck and keep us posted.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7