Originally Posted by dagst1
Hello and welcome!
You will have to remove the furnace to access the internal parts. To do so you would need to remove the vents from the outside. Depending on a lot of things they may come out easy of it may put up a fight. Then remove any flexible duct work from the furnace, disconnect the gas after you turn it off at the bottles, disconnect the wiring, remove any screws holding it to the floor and remove it thru the return vent opening. Then you can remove the case to access the furnace itself..
Before you do all that what is it doing or not doing?
The fan runs for a little while but no ignition.
I suspect the sail switch because the furnace lights and runs for a little while if I spray compressed air from a computer dust removal can into the intake vent.
If it is that much trouble to get to the sail switch, I think I will also replace the control board just so I don't have to remove it again if that is the issue instead.