BigFella

We are having a problem with our furnace in our 2019 Jayco 26BH Jayflight and for some reason the blower will come on and blow for about 2 minutes but burner won't light up. We've turned up thermostat and nothing changesd, checked exhaust vent and looks good, purged the propane line downstream from furnace to make sure no air in lines. Still acts the same. Reset thermostat and breakers and still the same result. Any ideas. Unit seems encased in wood and screen box and no access to furnace to check things. Anyone else having these problems or any suggestions would be greatly appreciated! Thanks and happy RVing to everyone!! Big Fella