qs271a

I'm having a problem getting the furnace on my 2018 jayco eagle 317rlok to light. So far I've had it pulled out twice. When I do this, and purge the gas line, it starts fine. I then shut it down and put it back and screw it down. Then I go in and try to start it again and it won't light. It will start to fan, and then after about 30 seconds it shuts down. I've checked for loose connections, gas supply, the thermostat, re-purged the gas lines twice, and the hook ups on the unit itself. I'm totally at a loss. Next move will be to call a tech out to look at the circuit board, or ignighter. It is still under warranty. We are getting ready to live in it temporarily while we get our house finished. And WINTER IS COMING! Thanks for any help.