RV Repair: t-stat, limit switch, furnace

Question
in order to get my suburban p30s furnace to ignite i have to turn the t-stat down and then back up and it will light but when it shuts down again i have to do it again.do you think it is the t-stat?

Answer
Hi Terry, If the furnace is coming on getting hot and runs though the cycle on then comes back on, but will not light the second time. I would say its the limit switch. If it just dose nothing after the first cycle, then I might look at the T stat. Good Luck.