Furnace noise

This is a wild guess and totally without merit but could the fan be dirty and possibly out of balance?

Our propane furnace blower loud GRRRRR sounds like sitting in the last two seat rolls of a M80 jet airliner to us...

Wakes me up every time it kicks on...

With this in mind it has become our backup heater with a very low setting of around 40 degrees. We heat with 120VAC Oil Filled heaters and electric blankets when hooked to shore power. We are thinking of switching over to HYDRONIC heat using our 6-gal hot water heater as heat source and yank that loud puppy out of there.

Roy Ken

Thanks but fan isn't dirty (cleaned anyway).

Anybody have other thoughts?

Maybe the plastic hose leading to the outlets has a tear in it, and is flapping?

toolman1 wrote:
Maybe the plastic hose leading to the outlets has a tear in it, and is flapping?

Wasn't aware of a "plastic hose" - where can I find that? If you referring to the interior hoses which transport heat I made sure those are tight/OK and not contributing to noise.

Ours has started that also, sounds like the fan is loose/wobbly until it gets going faster, then the noise stops like centrifical force corrects the wobble. We cannot find anything to tighten and all seems fine when checked. Another forum indicated that the fan motor may be going out when this happens. I guess eventually we will find out. Ours is in a 13 year old coach, not sure how much it was used the first 10 years, but we have used it quite a bit in the 3 years we have had it.

Foreign object? Our furnace got very loud after a year of use. Couldn't sleep with it running. Techs found the installation instruction sheet had been left in the furnace/blower space by the factory. It had gotten lodged in the fan. Removed it and all was well.

Maybe the bearing in the fan is going south.
Get in there and grab the fan and wiggle it to see if the shaft wobbles. It might have a bushing as opposed to a bearing - I don't know.

It seems that you are checking all around in and out of the squirrel cage (assuming that furnace is built that way).

I had a mud dobber build a nest in one - what a surprise. Ever since then i have had a screen on the intake and exhaust ports.

Thanks for the comments - I have checked the squirrel cage it turns fine and I can find no obstruction.

In reviewing furnace noise threads I had come to the conclusion that worn bushing/bearings result in squealing noise not the kind of noise I am hearing. Would/could a worn bearing create a "non squealing" noise?