Atwood Furnace 8525-IV DCLP Ignition problem

UPDATE:
I received the sail-switch from American RV Company, and finally got the time to install it.
I had to take the cover off the blower motor, and the switch was located on the inside wall of the cover.
Replacement was easy, but time consuming... took about an hour, start to finish.
Furnace is working like a charm. Thanks everyone for hints and suggestions.
Al

Thanks for the update!

Well, I tried. I took the door off, disconnected the reset switch, and took the 7prong plug off the board. Then I took the fan housing off, and the Sail Switch was mounted on the underside of the housing. I blew all the dust out of it with my compressor. Blew the dust out of the squirrel cage and exhaust area. Then I plugged all the electrical back in, and turned it on. Then I let the blower blow about 30 seconds, and then I held the sail switch on, and the gas igniter worked, and the burner came on! So it worked while I held the sail switch on. Then I put everything back together, and it didn't come on after all that.
Therefore, I have decided that the Sail Switch isn't working without help, so I'll order that switch and put it on. Then maybe it'll work as it is supposed to. Anyway, I feel better about things than I did yesterday.
Thanks, everyone! This is an awesome forum!!
Al

alenk wrote:

schlep1967 wrote:
Here is a troubleshooting guide that should help. Linky

Thanks for trying... but your link is for a Water Heater... my trouble is with my furnace.
Al

sorry about that.

To enblethen:

I located on the Atwood Website, (finally) the 8500 series manual. And I located the Sail Switch location... Now I have to try to get to it, and blow it out.
Thanks. I'll post again if this does the trick!
I really appreciate everyone trying to help me out...
Al

schlep1967 wrote:
Here is a troubleshooting guide that should help. Linky

Thanks for trying... but your link is for a Water Heater... my trouble is with my furnace.
Al

Here is a troubleshooting guide that should help. Linky

Open outside access, look for a Blue wire coming off the time delay relay, follow it to the sail switch located in the fan housing. Only a small rectangular part will be showing and the arm of the switch will be inside the housing.
I would get a can of compressed computer air and blow the furnace out paying attention to the sail switch area.
I am looking at an Atwood manual. Not sure which model you have and whether it has a time delay relay separate or on the circuit board. Either way the blue wire goes to the sail switch and comes back on a white wire to the thermal cutout.
Slide down on this site to the portion for furnaces. Locate the second Atwood furnace manual. See if it helps. It is under the hydroflame "04
Manuals

hbhconstruction2010 wrote:
It sences airflow on the exhaust side.

I can't find that switch. I removed the exhaust pipe. Where is the switch in relation to that exhaust pipe. Is it inside the heater?
Thanks...

midnightsadie wrote:
just a guess,, does the stat have a battery in it?? and your 12volt battery is charged? they need 12volt to run. even on shore power.

Yes. The fan comes on but will just go off after the fire will not ignite.