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Topic: Atwood Furnace problems (Read 925 times) previous topic - next topic

Atwood Furnace problems

I need help please. Freeze tonight and rear Atwood furnace has quit. It ran fine two days ago for testing but is trying to freeze up today. Bearings are dry.
I took all I can off the outside door and blower but can not see how to get to the motor bushings or get the unit out of its hole.  Any help will be greatly appreciated.
Thanks in advance.

Re: Atwood Furnace problems

Reply #1 –
The fan motors have BUSHINGS, not bearings (sadly).

The can be lubed with any light viscosity non-detergent oil such as sewing machine oil.

Apply to both ends of the motor and let it wick in.  Not always a permanent solution.

And, yes getting to it does take a few minutes from the outside access door.

Re: Atwood Furnace problems

Reply #2 –
Thanks Brett.
I have some turbine oil for the bushings just can't get to them. I would like to find a way to get the furnace out and do the work right on the bench.

Re: Atwood Furnace problems

Reply #3 –
Actually, that is more work than just accessing it in place.

Re: Atwood Furnace problems

Reply #4 –
I was surfing the iRV2 site the other day and someone had posted the link below in hopes that it might help one of the forum members there with his Atwood furnace problem (he planned to replace the motor).  I doubt that all Atwood's are created equal but surely they are similar?  If so, the video may help......some.  The well-meaning folks who created the video did a woeful job; the tech's back was toward the camera a LOT of the time and the wind noise was awful, but at least the narration of the sequence of events might be of some help in just "getting to" the bushings.  FWIW:  https://www.youtube.com/watch?v=d7YTOcSPOyI 

Best of luck..................ed s

Re: Atwood Furnace problems

Reply #5 –
Donald, Brett is right, best way is to remove motor and squirrel cage fan and use penetrating or similar oil to free up motor.
Real rough way is to use similar substance with a long tube and reach thru squirrel cage to get as much lube as you can of the shaft right at the end of the bushing.  Crude way to do it.
Gary B

Re: Atwood Furnace problems

Reply #6 –
Donald,

Brett and Gary are right.  You really need to remove it to work on it properly.  I also watched the same video that Ed posted before removing mine.  I removed my rear furnace back in february and after cleaning, realized after 20 years it needed a new burner which was rusted out.  The burner is hard to find on an older model.  After cleaning, oiling and replacing the burner, I bench tested it before putting it back in. It now works like a new one.  Here's my post on the subject.

What did you do to your coach today III

Good Luck,

Jerry

Re: Atwood Furnace problems

Reply #7 –
Thanks for all the help everyone. I now have the furnace running like a new one. It is getting dark, windy, and cold but inside of coach is nice and warm.
Thanks for the link to the video Ed, it was very helpful.
Jerry that was a great write up on your furnace rebuild. I was planning on doing it the way you did before winter but winter snuck up on me. I did take my burner out and cleaned it while I was working on the motor.
Brett I believe you are right, taking the hole unit out would be more work than I had time for being I was running out of time with the weather.
I removed the motor and drilled small holes in both ends of the motor caps and lubricated the end caps with turbine oil. After it took the oil I ran it on my work bench and you could hear when it got the oil. Runs smooth now.
Thanks again everyone.

Re: Atwood Furnace problems

Reply #8 –
Turbine oil is the correct lubricant for any kind of HVAC motor, whether it's a fan or a pump. The best is the "Zoom Spout Oiler" that you can buy at the hardware store. It has a long skinny spout that will reach in a long way. Be careful not to push the spout all the way down into the bottle when you're done with it... Doh! ...not sure how I know about that ;)

Don't ever use penetrating oil on anything other than a rusted part that you're trying to free up. WD40 for example, will turn to gelatin in cold weather and gum up moving parts.

Re: Atwood Furnace problems

Reply #9 –
Quote from: coastprt –

What did you do to your coach today III


I was testing my furnaces today for the upcoming winter season ( not much here!) and couldn't get the rear furnace to light after repeated tries.  I removed the whole furnace, cleaned out the mud daubers and replaced the burner about five years ago.  See my post above.

I could hear it go through the start-up sequence with the fan on, sail switch on, gas valve on and the igniter clicking. I could also smell the gas in the exhaust but no light up. I didn't think the burner or igniter were bad. 

This time after watching this excellent video from Darren Koepp Mobile RV Repair Service - Port Angeles Area - My RV Works I only removed the burner assembly and discovered there was more than a 1/8 inch gap between the burner and the igniter. This was enough gap to prevent the gas from igniting.  Simply bending the burner upward towards the igniter closed the gap to the proper height to allow instant light up. If your having the same problem I would suggest trying this check on your burner and igniter gap.  It may be your problem and it's an easy fix!

Jerry

https://www.youtube.com/watch?v=AB69oqtSiwc&t=19s

Re: Atwood Furnace problems

Reply #10 –
I found a good source for small diameter soft tubing when I had my cancer surgery. The hospitals throw away all kinds of this tubing that is used for IVs. Most of the time it is used for saline solution so it is safe to use. Tape one end to a straightened metal coat hanger or a small diameter wood dowel and you can reach in to very difficult places easily.

Re: Atwood Furnace problems

Reply #11 –
I worked on the front furnace today after working on the rear furnace igniter gap problem last week.  It would go through the start up sequence but not ignite.  After 25 years I suspected the burner was bad. Seeing it out I was surprised it worked at all!  If it did work it wasn't burning the propane efficiently. 

I had a good used spare burner (hard to find for this model) I bought from a local rv repair/parts store a couple of years ago for $20 bucks.  Removed and cleaned the orafice which was partially clogged.  I also cleaned out the debris and old mud dauber nests in the burner tube and exhaust tube. I now have screens over the exhaust vents!  I made sure the igniter gap was about 1/8" and also the the igniter was about 1/8 " from the burner (very important). 

Put it all back together and now it fires up instantly after the start up sequence and stays lit like it should.  These older furnaces if not rusted out can be R&R'd easily with burner parts that are still available. The only improvement I could use for now is the fan control board from Dinosaur which shuts the fan off after three unsuccessful lighting attempts. 

Jerry

Re: Atwood Furnace problems

Reply #12 –
I made sure the igniter gap was about 1/8" and also the the igniter was about 1/8 " from the burner (very important). 

In my opinion, this little spec, the 1/8" distance from igniter to burner surface, is not mentioned enough.  I did much tinkering with my 16K BTU furnace when I replaced the burner, which fit nicely but was a little different shape than OE burner.

jk