Atwood Furnace Not Working

[bsmcron]

OK, so I went out to start looking for any issues and to start getting ready for the upcoming season. I have a 2016 Cougar 337FLS and we have not done anything other than bring it home a couple of months ago. I started with the furnace. I set the thermostat to furnace and nothing. The blower should start and run prior to the furnace coming on but nothing. I checked for correct voltage and fuses and all are good. I removed the outside cover to gain access to the parts area of the furnace and see the red light blinking. I looked up the code and it shows Limit Switch/Airflow Problems. Being as it has not been turned on I am ruling out the limit switch and figuring it has to do with Airflow Problems since there has been no air moving to keep it from faulting out. From there I checked power at the on/off switch at the furnace and do have power going into the board (plus the red light was blinking) right at 13 volts. From there I checked the power going to the power to blower tab going into the circuit board and again right around 13 volts, I then checked the tab that would be providing power to the blower coming out of the circuit board and there is no power coming out to start the blower. Unless there is something else I am missing then I am now assuming it is the circuit board not functioning correctly to tell the blower to come on and start the sequence of events necessary to get the furnace to fire up. Is there something else I may possibly be missing? Thanks

[chuckster57]

Never just "rule something out" without testing it. A good limit switch will show continuity.

[JRTJH]

I agree with Chuckster. I've seen several limit switches with corroded contacts that won't provide current to allow the furnace to operate. So, maybe it is, probably it isn't, but stranger things have happened, so always check and never assume......

Here is an excellent Atwood Furnace Troubleshooting Guide: http://bryantrv.com/docs2/docs/hflamefurn04.pdf

ADDED: Here is another good source of information about RV furnace troubleshooting: https://www.rvda.org/App_Themes/RVDAMercury/docs/Sept_Oct_2014_RVTech_FINAL.pdf

Heck, it even has pictures !!!!! LOL

Good Luck and keep us posted on what you find.

[geobet]

Don't know if this will help, but I had similar problem last week. Blower would kick on but burner wouldn't stay lit for more that 7 seconds. Long story short, I pulled the plastic cover plate that surrounds the exhaust. Pulled the exhaust tube and didn't find any obstructions. Left the plastic cover off and fired up the furnace. It worked! Cycled on and off just like its supposed to. But, living in florida, I'll wait until the next cold spell to see if it still works.

[bsmcron]

I guess I am going to take it in to get looked at. I actually found a Place only 50 miles away to take it to rather than the 150 from where i bought it. Thanks for all the input.