My furnace did not come on the first firing of the season. After investigation found a reset button on a limit switch located near the pressure switch tripped. Reset the limit and everying ran fine, the burners kicked in, the blower turned on,etc. until the reset button popped out again. If I unplug the wires to the plentum switch, the flame goes off, but the fan continues until it is cool enough to turn off. If i reinstall the wires on the limit, the burner will re-ignite, the fan will come on after the furnace warms. I did notice that if I tap on the pressure switch sometime after the burners come on they will turn off, then after the fan cools the system down, the burners will re-ignite. Is either the plentum limit or the pressure switch suspect or am I missing something here? - This stuff is not rocket science but I don't work on many to have the experience to figure it out Thanks