Noisy AC vent, safe to brace with duct tape?

I just moved into a new condo, which has an AC unit inside a utility closet by the kitchen. I just discovered that while the system is on, it makes a loud blowing noise and a constant screeching vibe noise. The blowing I think I can live with, the screeching is driving me nuts.

The vibe is being caused by the intake vent above the utility closet; the grille is vibrating. When I take two 1/4 wide strips of duct tape and attach them vertically across the grille (shown here). This appears to eliminate the vibration. I’m fine with this as a semi-permanent fix, as long as it’s not going to damage the AC by interfering with the return flow or anything. Is there risk of that?

There is no way that your air flow will be obstructed.
But INAACE (I’m not an air conditioning expert.)

Also, try touching each slat till you find the ones that vibrate and place a small piece of blu-tac between the slats to hold them rigid. (trial and error)

It is not going to damage the A/C, but duct tape is notoriously ill-suited for taping ducts. :slight_smile: (Really.)

Duct tape in such a application seems to be a temporary solution that tends to work itself loose and refuse to go away with the next re-duct-taping. But that is not really blocking any airflow of any significances. Also over time will get a hard to remove tape residue stuck to it.

I have some questions for you:

*The vent in the pic–is the air coming out or is this a return vent?
*I couldn’t tell from the pic–are the vanes (the horizontal slats) louvered? Are there spindles on the ends of each slat that would allow you to tilt each vane up or down? If this is the case, tilting each vane into a parallel/horizontal position should get rid of the whining, and if that vent is making the excessive blowing noise, it should make that slack off, too. No duct tape residue.

Rather than putting tape on the front, you might be able to solve the problem from the backside of the edge of the grille. I would take the grille off and put some wads of tape, foam rubber, or some other small soft material between the grill edges and the wall. You should be able to do that without it being visible at all.

control-z has a good take on it, but be VERY patient with the grate if you do take it off; they strip out SO easily when you go to put them back on. Swearing helps, use it liberally.

Is there a filter behind that intake? I’ve lived in a couple of homes where there’s just enough air flow around the filter for it to buzz or even squeal if the filter isn’t placed just so. In one house, it was a handy “change filter” indicator - air would start to bypass the dirty filter and make noise.

I am not an eir conditioning expert but I’m really good.

You’re fine, the amount of airflow that you’ve blocked is considerably less that what gets blocked just by dust accumulating on the filter. Hell, it’s less that what’s getting blocked by the slats themselves.

Having said that, if that does the trick, I’d run to Home Depot and get some white electrical tape and use that, it would be less ugly. You might also ask the maintenance guys at the condo to put a different cover on that doesn’t rattle as much.

Also, someone upthread suggested putting the tape on the inside. In my non-professional but “I do a lot of HVAC stuff at work” opinion, I wouldn’t do that. At some point it’s going to fall off. It’ll probably just get pulled into the filter, but it runs the risk of getting around the filter and making it’s way into the blower motor (annoying) or heat exchange (fire hazard).

I’ve just remembered that I once fixed a vibrating grill by tightening the screws.

They make tape for ducts that will hold up better then what you’re using so I’d do that for longevity. You’re not blocking enough air to matter the way you did it so any tape you use is fine. Go forth and maintain your sanity.

Thank you all for the responses. What was shown probably won’t be the final fix, but I wanted to make sure it was safe so I could consider it as a fix if necessary. I considered installing a new vent and asking the landlady to cover parts, but I like the idea of getting condo maintenance involved. Though this is a very small complex, and I’m not positive they actually have a maintenance team.

Either way, I’ll definitely try everyone’s suggestions, and it’s good to know that I’m not likely to screw up the system with tape. I figured as much, but better safe than sorry.

What do you mean “strip?” Are you saying that the screws have a tendency to strip?

I wasn’t suggesting putting tape on the back of the grille openings, but around where the grille edges meet the wall and screws into whatever it screws into. That way any vibration that the air passing through the grille makes should be dampened if not eliminated.

After changing HVAC filters for many years I can’t see how some balled-up tape or foam around the edges of the grill would get sucked into the unit if A) The tape or foam is pressed between the grille edge and the wall and B) The filter is in place and fits tightly like it should. If the filter doesn’t fit tightly then it isn’t doing its job. You can buy foam weatherstripping with a sticky back that could be stuck onto the inside edges of the grille.

I probably should have said “cross-thread” instead. Sometimes, the duct work is bent back to provide a flange to screw the grille onto, and the screws can become cross threaded–the grille will still fasten to the flange, but the screw head could get off center.

Sometimes, the duct work is large enough that it fits between wall studs and then the grille fastens to the studs; those holes could strip.

Be sure each screw goes back into whichever hole it came out of. You never know what “the maintenance guy” is using for fasteners, and if you get a mismatch, there could be (a tiny bit of) trouble.

Ah, got it. Thanks for the heads up!

You wouldn’t happen to know what the technical term for that kind of vent is, would you? I tried searching on Home Depot for something that looked like the right size and configuration, but they seem to have many different kinds of vents and I’d like to narrow down the search.

Nevermind about the vent type. I was looking in the wrong section.

You probably have this fixed by now but poor purchase of screws because of lack of backing is usually the problem with such vent covers. Good HVAC installers will bend wings off the duct to provide backing if appropriate framing doesn’t exist. If neither exist drywall anchors rarely help much due to proximity to the drywall edge.

Glueing the vent cover on with dabs of silicone and taping until set or using a thick double sided tape like No More Nails tape work well. It is necessary to cut the tape / silicone with a knife or razor when removing the vent though or the drywall paper is likely to tear.