Loud noise coming from furnace on new camper

[twalker50]

I have a 2020 Flagstaff 21FBRS. Last night I turned on the furnace for the first time as it got a little chilly out. At first it sounded normal, about the same sound as an air conditioner running but after it heated up, about 2 or 3 min, it started making this loud sound, almost like a buzzing sound. Can anyone tell me what this could possibly be? You would think that it was a fan noise but when the furnace is cool, before it heats up, it sounds normal.

[Bama Rambler]

Does it do it every time you run it?

It sounds like the blower is hitting the housing when it heats up and expands.

[5picker]

Yep... it is really hard for us to surmise what it might be without being there.

It really shouldn't sound any different once hot than when cold with the exception of you could hear the burner ignite and run. Mine rumbles ever so slightly more when the burner is on but I wouldn't say it is loud or buzzing.

Can you post a video?

It is possible a piece of construction debris or something got sucked into the blower wheel but we are simply guessing.

[NJKris]

I just started a thread on this for GeoPro/Epro trailers. The Suburban furnace, used all of maybe 3 times in past 2 years, is making a buzzing/rattling sound around 10 minutes into cycle. Does not make sound when cool and fan is running, so I'm thinking a bad bearing, or something else with one of the hamster wheel fans like the other posters mentioned. The Suburban authorized repair center is almost an hour and a half drive from me. Rather than tow the whole trailer up there, I"m going to try to pull furnace myself, they said they can test it on the bench up there. Can't wait to see how much fun it will be trying to pull this darn thing out of the counter cabinet! Warranty expires in 9 days.

[downeyr]

This has happened to me a couple of times and it turned out that a mounting bracket for the control panel had come loose or had never been properly mounted.

[NJKris]

So I pulled a drawer and the intake air screen from the cabinet to reach the furnace, and inspect how it is mounted for potential removal. The good news is it doesn't appear to be too much of a pain to remove. So I test it again with this stuff removed, no noise! I did notice the outdoor shower hose, which I had replaced with a superior, more flexible metal shrouded hose, was lying on the top of the furnace cabinet by the exterior wall. Maybe that was vibrating. Don't understand why it would only vibrate and make noise at the end of the heat cycle though. Will test several more times to try to duplicate the gripe. Maybe even intentionally let the hose rest on cabinet and see if that is what it was.

[NJKris]

Originally Posted by downeyr

This has happened to me a couple of times and it turned out that a mounting bracket for the control panel had come loose or had never been properly mounted.

Where was your control panel? I do not see anything on exterior of furnace cabinet, or when I remove front panel of furnace. Mine only has 4 wires coming out of side, which I assume run up to thermostat.

[twalker50]

Thanks for the replies everyone. I was trying to post a video or audio of the nose but apparently you can only post pictures. I'm going to pull out the drawers above the furnace this weekend to see if i can get a better look because it sure does sound like some kind of fan noise or something obstructing the fan as someone here has suggested. The camper is still under warranty so rather than yanking out the furnace myself, I will probably just take it back to the dealer and let them look at it.

[Joe_GA]

If you don't have a youtube account create one. They are easy to do. Once you have an account, upload your video, copy the URL (link) and past it here in your post. Easy peasy!

[eye95]

Originally Posted by Joe_GA

If you don't have a youtube account create one. They are easy to do. Once you have an account, upload your video, copy the URL (link) and past it here in your post. Easy peasy!

If there is another service that is not as invasive as Google’s YouTube, you might want to use it instead.

[Joe_GA]

Originally Posted by eye95

If there is another service that is not as invasive as Google’s YouTube, you might want to use it instead.

I quit using Google search for that reason. Is there a another service?

[5picker]

Originally Posted by eye95

If there is another service that is not as invasive as Google’s YouTube, you might want to use it instead.

Originally Posted by Joe_GA

I quit using Google search for that reason. Is there a another service?

Well... don't shop on Amazon, Walmart.com, eBay or click any links on this site then either. LOL! ...after all...it is the internet!

[eye95]

Originally Posted by Joe_GA

I quit using Google search for that reason. Is there a another service?

I can’t imaging that there isn’t. I don’t post videos, so I don’t know. I just avoid Google and Facebook like the plague.

As someone else said, I don’t click the ad links in this forum either. If a product catches my eye, I use DuckDuckGo to search for it. They are almost ALL shipped from China, so, no. I don’t care a whit about Chinese made. It’s Chinese shipping I hate.

If you click an ad link, a LOT more information is sent than just your request for a website!!!

[twalker50]

Loud RV furnace:

https://www.youtube.com/watch?v=HFkL_XNLE0Y

[NJKris]

Holy smokes, that's a lot louder than the buzzing issue I had, which went away after fiddling with ducts.

[SacRV]

Sounds like bad bearings to me.

[twalker50]

I took the camper to the dealer to have it fixed. They said that once the furnace was heated up, heat was warping a frame piece and the fan was rubbing against it causing the noise. Thanks for all of the replies.

[NJKris]

interesting. Thanks for update twalker.

[Average camper]

TWALKER50
when you took the camper to have the loud furnace corrected what did the dealer replace? I've found both times I've disassembled the blower fan housing that the motor is a fixed to plastic and it causes the fan to sag and rub the shroud. Anyone have a suggestion for repair? Can't believe its all plastic and the motor is just set in there and not secured.

[twalker50]

They didn't have to replace anything, they just bent (reformed) a piece of metal frame that the fan was rubbing against once the furnace heated up. This is just what the service guy told me. I didn't actually see what they "reformed".