Quieting Organ Pipes

jeff_25

first, check the grills some time they can be noisy also check balancing dampers jeff

Constantin

So, it's a quiet Thursday afternoon...

... and I decide to try out the AC system. Besides blowing a lot of wood chips from two registers, I also discovered a resonance... i.e. a loud, high-pitched whistling horn sound, just like you would get from a pipe organ.

I went around the basement looking for obvious holes in the accessible return ducting (which is not covered in insulation) and covered whatever holes I could find with pookie. The whistling sound has subsided some, but not completely. I was also surprised to find a lot of air escaping from the (insulated) supply duct work, which I also hope to adress with time.

I'm not exactly sure where to look first as the source is not evident. What do you guys look for, how do you look for such issues in duct systems? I guess I'll have to call the installer back....

Christian Egli_2

Pull out all the stops

High pitched whistling sounds are often found at the seams, particularly long seams that only open a long and nearly gapless crack. It is often compounded by a sheet metal lip geometry. This is often the case around a removable panel.

If the duct guy is good, it can be quite melodious, because if it isn't noisy, how will you know it is cooling? Bullet holes and such don't produce sounds, just leaks. Interestingly, consumer advocate Clark Howard has been pushing statistics about how much forced air systems leak and how much these leaks cost you because you are loosing air you paid lots of money to condition. He also talks about non-insulated air ducts.

To fix the noise

To stop the noise from the vibrating lip, or panel, or whatever else, hold your hand against it so as to dampen it. A small wedge shoved in somewhere makes this less tiresome. Re-crimping the offending seams should be more permanent. And the ultimate weapon is, of course, a roll of duct tape... Duct tape also cures air loss. If the problem is generalized to all your pipes, then try changing the air velocity (and pressure) to get away from the resonant frequency. Insulation would act as a damper as well and muffle the sound.

This howling will be a hoot at Halloween.

Constantin

Thanks Chris & Jeff!

I will be following your suggestions once I am back home. I did find a lot of seams that were not sealed with anything from the outside and presumably they weren't sealed from the inside also. Mastic is a lot of fun to play with. Much more forgiving than polyurethane foam.

It's simply amazing to be down there and to feel the air escaping out of joints, etc. More insulation/tape/mastic will follow and the dampers will be pulled to examine them until the source has been quieted. Thank you once again for the tips!

Empire_2

I agree w/ Jeff.

I had the similar sound that I could only hear from the upper master bed. Turns out it was the vanes on one of the register itself. Didn't do it all the time but after being annoyed for the last time, I stuck some of my magnetic business cards across the face and it stopped.

Not to say this is your problem, but give it a try. Turn the fan to on and experiment.

Good Luck Mike T.

Eugene Silberstein 3

Business Cards

Business cards usually do a better job when you give them to (potential) customers.

wink wink

Empire_2

;-)

Nice Eugeen....:-)

Mike T.

don_156

You would

be better off with the right grill.

Trash the sidewall because, they are junk when it comes to throw and noise.