Replacing Limit Switch in 8531 Furnace ?

[BFL13]

Since the pros are here today, good time to ask lots of questions!

Is there any way to replace the limit switch in an 8531 while leaving the furnace in place? It seems like you have to haul the whole furnace out (big chore!) and take it apart in the middle to get at the limit switch. True?

If so, does the limit switch have to go inside and up there? Could you run wires to a new one "mounted" inside by poking it through where a duct goes on, eg? (remove and replace duct or poke a hole in the duct and tape that hole up after)

Would the limit switch be effective as a safety device if mounted externally on the back where it goes now but on top instead of inside?

I really, really don't want to haul the whole thing out.

I believe it is the limit switch that is the latest bother with the furnace (replaced rusty burner tongue). The furnace comes on ok and runs for 15 seconds, fan keeps on, burner lights again for another 15 seconds, wait a bit, back on for another 15 seconds ( I timed it) all the way to the end where RV is up to thermostat setting and it shuts off ok. Cycles ok for days, but always does the on-off burner thing.

I can live with that instead of hauling the furnace out. The ducts and registers are not blocked. Burner etc clean. I have a spare limit switch that I could try out if it were easy to install.

Thanks

[BFL13]

x2 and my local RV repair shop also quotes an hour's work for that job. In my case, I think that is a bargain considering what is involved and my lack of the right tools. I would not know that if not for Doug explaining it.

[bob213]

Doug, if no one has thanked you today for your contributions on this forum let me be the first. Your contributions are invaluable. Whether I have the problem the OP has or not, I always learn something from your answers or explanations. Thank you.

[BFL13]

Thanks for that info Doug. Much to think on there.

[dougrainer]

Pulling the furnace will not get you to the limit switch. You remove the Blower wheel cover and blower wheel. Once that is done you can get to the Limit switch. I use a 14 inch 1/4 inch drive socket extension with a phillips bit on the end and use very long needle nose pliers to remove the 2 white switch wires. Remove both screws on switch and remove then install new and connect wires. Have a LONG magnetic pick up tool to get the screws if you drop them. Make sure the 2 white wires are NOT too close to the burner chamber when you are done. Doug

PS, The flat rate is .9 hour to do this