If your furnace is an Atwood, then it has an electronic spark igniter. Assuming you have an adequate supply of propane, then no ignition can be caused by several things. (1)no 12VDC to the control board, (2)bad propane valve, (3)bad electronic board, (4)bad air flow sensor sail switch......and there could be others. Rook
When you get a chance to dance, or sit this one out......I hope you DANCE!
98 National Tradewinds 7370, powered by a 3126B 300HP CAT Turbo, Freightliner XC chassis