How easy to pull furnace fan out?

Well, I finally got around to doing something about my furnace fan today.
It got so bad I had to shut the thing off.

Thanks Chris, for your excellent detailed instructions. I followed them and soon held the fan motor in my hand.

I am surprised it ran at all. The motor shaft was nearly completely seized. It was very difficult to turn with the squirrel cage on. With it off, near impossible to turn with my fingers.

I squirted some fine oil on the shaft, directed inwards towards the bearings, on both ends, and got the shaft rotating. It freed up very easily so I spent a little time working some oil into the bushings/bearings, whatever they are. Soon it was spinning freely.

There was a little end float in the shaft, but it was tight side to side.

I put it all back together and fired it up and yahoo! It is whisper quiet once again.

Thank all for your input.

sum1 wrote:
If you haven't done so already, try some creative ways to get some lube in there before you pull it out. I've used long tubes of the diameter of those on sewing machine oil (which works like a dream, BTW), specially bent lengths of coat hanger with q-tips taped to the ends and even a length of broom straw dipped in oil. This has given me years of extra service on fans from those that are seldom used to ones that work for hours a day.

Hey, just did it again today. The fart fan in my most used bathroom started squealing and growling again. A little sewing machine oil quieted it up again. Last time was about three years ago and it runs at least 2 hours a day. Installed in 1992. Now it's kinda becoming sport for me.

Old-Biscuit wrote:
W

Here is a service manual.....exploded view of 8500 series on pg. 40
LINK

BTW, Old-Biscuit,
Thanks for the link!

DiskDoctr wrote:
Please let us know you have heat again and that there isn't a Bobsicle up north! ;)

Well, no Bobsicle here! LOL!

Heat hasn't quit on me, but funny thing the charming noise from the fan is going away.... It hasn't happened for the last few cycles of the furnace.

I do have my handy dandy little plug in heater going. During the times when we are above freezing, it actually does the lions share of the heating. I just hate listening to the constant drone of the fan....

It has "warmed up" here substantially - the daytime temperatures have been above freezing. Almost ready for my shorts and flip flops! Haha!

But I will have to get into the furnace and pull the motor out to see whats up. If I need a new one, then I guess Ill get a new one. This thing has had more usage in the past few months than many get in a lifetime!

Please let us know you have heat again and that there isn't a Bobsicle up north! ;)

My previous 1998 5er had the same thing. Like Chris said... a long 1/8" allen and I THINK I also needed a long 1/4" nut driver. I took my motor apart to clean the sleeves with solvent and to oil them better. There were four tabs on each end that were bent inward to hold the end bells in place. I bent them out just far enough to get the end bells off. Don't go too far cuz they break easily... I've done several motors like that one. I had to rig up something to hold the brushes in so I could get the armature back in. It worked out great! Craig

I don't understand how manufacturers can build wiper motors, a/c motors, and many other motors that don't squeal like mad after 2-3 years, but the furnace manufacturers are still putting the same crappy motors in now that they used 30 years ago.

It's time they stepped up and built a quality product. Just my 2.5 cents worth!

Mine also turned out to be the squirrel fans they were moving side to side in the motor letting one side hit the housing. I just loosened the right side and pushed the left side fan to the right and the right side fan to the left then retightened the right side fan. No more noise and I didn't have to pull the motor.
See if yours has any movement side to side on the motor shaft that the fans are mounted on.

What Chris Byrant said ^^^^^^^^

You'll need the 'PF' number on motor to cross reference new motor.

Atwood made a change on motor style in 2004(?) and you might need new motor bracket kit.

Here is a service manual.....exploded view of 8500 series on pg. 40
LINK

Lousy time to be dealing with furnace........but that's when they go out.
Try to stay warm and don't freeze up the trailer...you've had enough of that :B

A friend and I pulled their furnace out last year. At the start of the season he installed the batteries in reverse polarity and blew the board. (oops)

If you have to pull it right out, easy to get out. You should install a plug for the end of the gas line to cap it off until you are ready to re-install it.

If you have to disconnect wires, there's a few in there that can be confusing. We made a detailed diagram (I thought), but when we went to reconnect it, something didn't seem right and I had to make up an extra wire with a connector. His kid may have walked off with a piece of wire, we just don't know. Taking a few photos may help as you disconnect things if you're taking a bunch of it apart.

We had to pull off the exterior vent cover to get the furnace out on his. They use a type of putty to seal it to the wall so you should get some new stuff for re-installation.

Getting it back in was a bit of a PITA as something kept hanging up on the enclosure. Getting the gas line tightened up again was hard to reach in. Unless you are confident with connecting gas fittings, I would get a bottle of gas leak detector to make sure it's a tight seal. If it doesn't fire up at first, there could be air in the line you'll need to purge. Opening a burner on the stove and getting it to light should do it.

As above, maybe you can just do it without pulling it right out and then you can ignore what I said.

If the fan assembly needs to be replaced, I'd suggest buying one online if you can wait. A local RV dealer will cost you a small fortune in comparison.

Otherwise, it's pretty simple. As per Haynes manual, installation is reverse of removal.