Fairly whooshy vent return problem

[caslon]

I just had a Carrier 2 ton AC and Performance 80 installed in a 887 sq ft. condo.
The return grill is in my hallway closet. 26"x16". With the AC going, it's
noiser than I would like. I have a pic for some suggestions to baffle or
reduce the sound. It almost seems that cavity is huge and could well
do with some noise reduction remedy. It's like a mini hurricane in there.
What I mean by that is that there's actually downward flow too and some
of the light insulation debris can be seen moving around by the turbulence.
It that normal? The duct work is pretty good sized round.
The vents on the walls are fine, sound wise.

Anyways, some ppl are limited to their return vent area to mess with.
I'm sure not. That white texture overspray is where air enters in.
I'd appreciate some baffle suggestions. What's better than carpet to lay on the floor in there?

[aintitfun]

By choking it down, most likely you are going to increase or at best just change the noise. You may see if you can have the installers, insulate this area, that will reduce the noise, but have them do it, because we are not talking about regular household insulation here. Unfortunately it will only get so good, do to it being almost directly at the blower. But it can be improved.

[dash]

Quieturn vanes ,will do the best jo,IMO.


Go to www.durodyne.com

then Glassline Catolog,look for Quieturn Vanes.

The space can be lined with ductboard,which wiil hold the vanes in place,
.

Chances are you'll need to show the vanes to your Pro,as s/he may not be familar with them.

[Weaselboy]

Interesting. Where would you position the vanes in his installation?

[dash]

Interesting. Where would you position the vanes in his installation?

Hard to describe.A box the size of the equipment inlet,down to the floor, would be built to hold the vanes.Vanes would be installed at the needed angle,not 45 degrees in this case.

Then a transition from the inlet to the box,flaring out going to the return grille size.

Ductboard is ideal as all this can be cut and fitted in place at the jobsite.Mastic on the inside seams is ideal to hold it all in place.

[sparks]

Is that Air Cleaner new? Looks like it, i don't see a transition on it and I wonder what the static is across that. Have the installers check the T.E.S.P of the system. The whooshing sound and turbulence could be from the flanges on that cleaner.

[Poodle Head Mikey]

So you want to avoid a straight path for the air to follow and you want the flow-path to be very smooth.

First: did they do a heat load calculation to determine that you actually need 2 tons of cooling and the aproximately 800 cubic feet of air flow for it?

Next: did they test to prove that you are getting the correct airflow? Or did they just set the blower for "the highest speed for cooling" and run out the door with the check? <g>

After the above two questions are answered correctly, and if you can tolerate the loss of space, a blank, well overlapping 'baffle plate' can be spaced out from the wall to cover the return opening.

Or two sets of 45 degree vanes could be installed internally in the air return path.

[dash]

Is that Air Cleaner new? Looks like it, i don't see a transition on it and I wonder what the static is across that. Have the installers check the T.E.S.P of the system. The whoshing sound and turbulence could be from the flanges on that cleaner.

Good point,also wonder if the platform is cutout the full size of the air cleaner,if not more restriction and noise.

[sparks]

Good point,also wonder if the platform is cutout the full size of the air cleaner,if not more restriction and noise.

Yeah, you can't really tell from the pict's but it looks smaller than the inlet.

Hey caslon can you post a few more pictures it may help us help you. Supply transition, where the furnace connects to the duct work and one from the return to the bottom of the air cleaner.

I don't know how much we can help with just pictures but maybe we can give you a few more ideas to approach the installers with.

[caslon]

First of all, thanks for the replies. I believe the whooshing noise CAN be lessened...somehow.

I noted to the installer before he left that the whooshing sound seemed excessive. He said it was the blower motor sound being in such close
proximity to the return cavity. He didn't seem to want to do much about
it, seeing as how the system was working pretty well.

They offer 100 &#37; satisfaction guaranteed, but if they aren't talented enough to
deal with it...what good is that?

I will DEFINATELY explain to them that I am getting so much draw that I can
actually feel backpressure air coming out thru the return grate. To me that is
just wrong. That is priority # 1....don't you guys agree?

Can the blower motor speed actually be tweaked? I thought you didn't want to do that.
Also, the cutout IS the full size of the filter, btw.

If my return cavity space was farther away, I probably would not have this problem. The sound isn't maddening (but excessive), and that backflow of air coming out the return grate COULD/SHOULD/CAN be corrected IMO.

[caslon]

Hard to describe.A box the size of the equipment inlet,down to the floor, would be built to hold the vanes.Vanes would be installed at the needed angle,not 45 degrees in this case.

Then a transition from the inlet to the box,flaring out going to the return grille size.

Ductboard is ideal as all this can be cut and fitted in place at the jobsite.Mastic on the inside seams is ideal to hold it all in place.

I understand for the most part, but that flaring out to something the full size of my intake opening seems a bit much for to want to have fabricated.

How about this: Run the box down to an insulated floor like you said, then
with the 6" clearance on each side, run out 4" sideways on each side with somewhat smaller
ducts (big, but not 24" big). Remember, rectangle filter opening is 24"x12".
That would give 2" clearence on 2 sides for the air to get in and
take 2 right turns upwards. I could even sound insulate the inside of
the sheet metal. Ample flow of air would still get to the filter and there
would be not one, but 2 right turn ducts at the bottom. I may not even
have to use those vains (or could).

With how oblong a retangle it is now, that rectangle gets up to the front in a hurry. Too much so for your design.

[dash]

With ductboard you just cut and fit on the job,very esay for them.The other reson to use the vanes is to have the airflow evenly,as directed by the vanes,thru the filter.3 to 4 feet of stright would do the same,but not possible.



If you follow your plan,ductboard is easier then metal to fab.

[TrueAirBC]

This may have been over looked, but a very simple solution to your problem is to buy a grill with larger louvers on it. Get one with more space in between them, this will if nothing at all lessen the noise.
I did a few jobs where the unit was right ontop or directly beside the r/a and insulation helped but the grill let the air flow through easier and reduced the noise by over 50&#37;. If you have to you can get a custom grill made up with 1/2" x 1/2" square. Egg crate is what we call it here.

[caslon]

With ductboard you just cut and fit on the job,very esay for them.The other reson to use the vanes is to have the airflow evenly,as directed by the vanes,thru the filter.3 to 4 feet of stright would do the same,but not possible.



If you follow your plan,ductboard is easier then metal to fab.

OK, ductboard is easier, but I have that center 2x4 at the front. Each
square measures 11"x12" opening size. Might be a bit iffy.

Just for kicks I threw down an old bath rug on the cavity floor, and a
12" x 18" USPS shipping box fit perfectly up at the front of the rectangle.
Right there that cut the sound by at least 15%.
I do plan on using some type of sound absorbing board and line the rest
the walls in there.

First I wanna see why I'm getting such a back flow
of air pushing down from the filter. Shouldn't a return intake draw in air only???
I'm calling the installer back. Maybe the blower motor could be turned down a tad, if that's even possible.
Some things need fixing on this install. I'm can feel a few minor cold air leaks at some areas at the evaporator, and there's a stream of air coming down at the plenum where it enters the attic.

[TrueAirBC]

Is the furnace noisy when the grill is off? If not that is a big part of your problem. Like I said below, its sounds like a restriction problem caused by the grill.

[caslon]

Is the furnace noisy when the grill is off? If not that is a big part of your problem. Like I said below, its sounds like a restriction problem caused by the grill.

Hehe, no. I've had the grill off for days now working on this. I set it back on
with one screw just to hide the ugly cavity.

With that backpressure from too powerfull an uptake, its affecting the thermostat right across from the AC closet. The air backs out of the
return vent and makes for an inacurrate high current temp on the thermostat.

I gotta get that looked into for sure. I think I can work out the sound problem
myself once I get this entire install thoroughly checked out by them.'

I think I'll ask for another of their crew tech to fix all this, not the original crew installer.
Nothing like having the original guy cover his ass with a bunch of quick fixes or something.

[Poodle Head Mikey]

Calon,

You wrote:

1. . . . too powerfull an uptake

2. The air backs out of the return vent . . .

3. . . . . and makes for an inacurrate high current temp on the thermostat.
----------------------

Those things don't go together.

You can't have both a powerful suction / air flow into the return, AND, air coming in the reverse direction Out of the air return.

Maybe I misunderstand what you are saying? Can you explain that to me again?

PHM
--------

[TrueAirBC]

I realy think if you allow more air to get into your furnace all problems will be solved. Tell them you want a girll that gives you more free area

[aintitfun]

Man, am I tired of seeing the word WHOOSHY

[caslon]

Calon,

You wrote:

1. . . . too powerfull an uptake

2. The air backs out of the return vent . . .

3. . . . . and makes for an inacurrate high current temp on the thermostat.
----------------------

Those things don't go together.

You can't have both a powerful suction / air flow into the return, AND, air coming in the reverse direction Out of the air return.

Maybe I misunderstand what you are saying? Can you explain that to me again?

PHM
--------

First of all, I know it sounds wierd, but I am guessing you CAN have an uptake of air at the return and at the same time some kind of backpressure or whatever where you can feel air being driven back down into that return cavity and out of the grill. We can go no further if you think this is an absolute impossibilty.

Second of all, I am a painting contractor, not an HVAC contractor, so I may have jumped ahead as to what is causing it or the mechanics of it all. Sorry.

It's almost as if there IS air being correctly sucked in, but at the same time, so much so that some is actually being forced back down into that same return area.

Trust me when I say I can feel air being expelled from the return intake grate.
That air rises up to the thermostat directly across from the intake grate and affects the current reading temp of the thermostat.

At least read back my entire post, all of you. Someone reads my latest post and tells me to get a bigger intake grill, then repeats the same suggestion.

Any and all info you want me to provide, I will. Read back to the beginning and at least check out my freaking pics. No offence intended to any.

PS. The Honeywell F300 electronic air cleaner is supposed to allow as free a flow of air as any
regular filter. In fact...this model does NOT have a post filter. So I can't see that as the cause.

To sum up. At the same time I'm getting air drawn in, I'm getting a lot of downward air at that same return cavity. Unit sits in a closet, directly below is the return cavity. I'm feeling air being forced out the return grill. I don't know how much more simply I can put it. NEW INSTALL.

Of course...any and all help welcomed. Oh ya...I'm having those guys back here...lol.
Otherwise..the AC is cooling pretty well. Some minor air flow leaks at other areas in the closet I should probably not feel with my hand. Probably minor.