The
"heater limit switch" component went bad in my Suburban propane furnace and gave me similar symptoms to what you're experiencing, jkackley724.
Suburban Furnace Replacement Limit Switch
Manufacturer's Number: 230635
Suburban Furnace Replacement Limit Switch - $10.99
(By the way,
this is a separate component from the thermocouple --- the thermocouple resides directly against the flame front, and shuts off the gas promptly if it senses that the flame has gone out.
By comparison ---
the heater limit switch is designed to shut down the furnace if the overall furnace unit itself is running too hot. And its failsafe mode (if this component fails) is to shut the furnace down too. So if its gone bad....you get sketchy furnace behavior....)
For reference, the unsatisfactory heater behavior I observed:
The furnace would fire up (once!) and run just fine, happily heating up the van (to the thermostat setting....) but then after it had shut down...and the van had cooled down enough again to trigger the thermostat to fire up the heater again.....it just wouldn't fire a second time to heat the van. It would definitely keep trying (you'd hear the blower kick on, and the ignitor try several times and then give up....but the blower would keep running.....yet no flame, no heat.....)
Easy to swap in a new one of these heater limit switches, maybe worth a try.
EDIT: By the way, hat tip to forum member
capnkurt for figuring this issue out with my heater!!!