RV Repair: Atwood 8500 series furnace wont light, stove burners, limit switch

Question
Hello, my blower motor went out on my furnace, I replaced it and now the furnace wont light. The sail switch does close, the ignighter sparks but it wont light. I have seen how everything operates and the timing of the fan motor, ignighter and all works as it is supposed to so I am kind of thinking the board is working but i dont know how to check the valve (propane and 110V) I know there is a limit switch that may be bad but I don't know how to check that either. can I purchase a repair manual for this? or can you help me over the phone (630) 327-4543 My name is Don and I would so appreciate some experienced help on this matter.
Thanks,
Don

Answer
The most likely problem is gas pressure. Do a quick check by simply lighting stove burners one at a time and watching carefully for a change in flame size in the other burners as additional burners are lit (if they get smaller each time, your pressure is too low). The valve can usually be diagnosed by simply listening or touching it - there should be an audible click. The fact that it does spark eliminates the limit switch. Check these items, let me know what you find...