Awful noise from furnace

[SF1911A1]

I have a 2013 Rockwood Roo 233s. I bought it this past December and used the suburban heater once right when I bought it. It worked fine although the heat output was less than I would have expected, this is my first camper and I don’t really know what to expect. It put out a slow flow of heat from the vents. Last week I took the camper to Arizona and ran the heater at night. I woke up to a terribly loud vibrating type noise. The best comparison I can think of is it really sounds like I’m running a generator. It’s so loud I jumped out of bed and tried to get it to shut off as quickly as I could because it had to be disturbing a pretty large number of neighbors.

I took it apart tonight and the only thing that looked out of place was one of the fan blades was broken off completely. I removed the broken piece and put it back together hoping that that would solve the problem, but it did not. Would a single broken fan blade out of about 8 or 10 blades be enough to throw the entire thing off balance and cause this noise? Has anyone dealt with this before? I did a search of the forum but did not see any posts like this. Thanks for any help.

[rjshiflet]

Originally Posted by SF1911A1

Would a single broken fan blade out of about 8 or 10 blades be enough to throw the entire thing off balance and cause this noise? Has anyone dealt with this before? I did a search of the forum but did not see any posts like this. Thanks for any help.

Short answer - YES one blade missing can throw it out of balance severely.

And yes, I have experienced this. Then I thought I'd just put up with the noise and not long afterward we had a very loud shattering noise. Basically the majority of the remaining blades came loose and the heat stopped because the fan could no longer blow.


These were plastic blades on the squirrel-cage type blower. We replaced with metal, and never had another problem and the metal is much quieter than the plastic ever was for some reason.

[SF1911A1]

Ok great, thanks a lot for the input. I wasn’t sure if maybe I had two problems and I needed to keep investigating. I guess that’s always a possibility, but I’ll start with the fan and hopefully that’s all that’s bad. Is there a supplier you recommend or just google it and find the best deal?

[DougW]

If you need to run the fan, until the new one comes you could remove a fin exactly opposite the one that is missing. That should balance the fan enough that you can run it a bit without damage.

[SF1911A1]

That’s a good idea that I hadn’t even considered. Luckily my trip is over and the furnace is not needed any more. I found the part number but only for a plastic replacement. I haven’t found a metal blade option yet.

[NXR]

I had one disintegrate like that after a few trips. The noise started off as a slight tick-tick, like a bug was bouncing around the fan. Then about 4:00 AM it came apart and I reacted the same way. Scared the heck out of me. It blew the fuse and that's when I learned the furnace and the fridge on mine are connected to the same fuse. <sigh>

That may not be a plastic fan but rather a composite fan. Mine is newer than yours and when I queried the manufacturer about using a metal fan I received this reply:

Dear Sir;

We regret to learn of the issue you have encountered.

The composite wheel is certified for use in the SFQ furnaces. Installation of a metal wheel would void any warranty. You will need to have the service center install the correct wheel part number 350206.

Ronnie Ellison
Service Manager
676 Broadway Street
Dayton, TN. 37321
Office: 423 775-2131
www.Airxcel.com

FWIW,

Ray

[itat]

Well, it could be worse. A YouTuber that I follow had a mouse get into his furnace squirrel cage.

https://m.youtube.com/watch?v=m8bYSF7Snbc&t=174s

[rsdata]

I would use a plastic replacement with no issue...

[DouglasReid]

When we purchased our previous camper the furnace would not run. I took it apart and found a huge mud dauber nest on the squirrel cage that had it locked in place.

After I freed it and cleaned it I found the bushings on both ends of the shaft were shot.

Apparently that nest had been there a while and the previous owners had run it with that nest in it, The out of balance condition beat the tiny brass bushings out.

a new motor, and I was $100 poorer but the fan worked perfectly til the day we sold the camper. I also installed screes on the furnace exhaust so the mud daubers could not get in again.

[SF1911A1]

I just wanted to follow up in case someone searches for this in the future. I replaced the fan today with a stock composite blade. It is now quiet as a mouse fart and smooth as glass. I was a little skeptical that the fan simply having one blade break off could be so catastrophically terminal but thankfully it was just that simple. Thanks for everyone who replied, I really appreciate the help.

[SF1911A1]

So after replacing the fan blade the symptom was cured but unbeknownst to me the problem remained. After running the heater again this season I started hearing a loud ticking sound that was not as bad as when the blade was broken, but still clearly not right. When I got home I opened the heater back up to see what was still wrong. When I removed the blower fan assembly I could see on the blade that something was touching the blade and starting to wear it away again. Looking into the furnace from where I removed the fan, I could see some sort of switch. It looked sort of like a straight razor blade, but it was not sharp and was weak metal like very very thin aluminum. It would rock back and forth toward and away from where the blades are. I simply bent the switch away from the blade until it looked like there was no way for the metal to get near the blade. I did not see anything else at all that looked like it could be the culprit, so I put everything back together and tested again. I ran the furnace for about 5 minutes and did not hear anything out of the ordinary, so hopefully this is now properly fixed.

While I was in there, I saw that the dryer vent that connects the furnace to the forward vent by the door was cut wide open and basically making the front vent worthless. I replaced the duct and now hot air flows out of the vent like it should.

As I said before, I wanted to keep this post updated for a future user having the same problem. I will update again if I have any further problems. Thanks.

[DouglasReid]

Good Job!!,

Both for locating the problem and sharing with this for other's benefit in the future.