Are my ducts noisy because of heat or too much air?

Page 2 of 3  
If it is a balance problem, would the noise show up at a duct or at the furnace? And how would I go about fixing it?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dom wrote:

Hi, They have to measure air volume in CFM and blower speed setting, etc. For quick check, you can remove filter for one night to see what happens. better or worse.... My BIL is a commercial HVAC design engineer who helped our system when house was built with high efficiency furnace and high SEER a/c both two stage units. Runs very well on wireless thermostat w/o the bother of wiring.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
This is interesting. Thanks a lot Tony. I'm going to do some research on filters and get ones that allow the maximum air flow, and I'll report back In a day or two to tell you if it helps or not. I still don't see what I c an do if it is a balance problem. Is there a away of fixing that? Who do I call to look into it?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dom wrote:

filters and get ones that allow the maximum air flow, and I'll report back In a day or two to tell you if it helps or not. I still don't see what I can do if it is a balance problem. Is there a away of fixing that? Who do I call to look into it?

Hi, You did not answer yet whether the problem came with the new furnace. If it started happening with new furnace maybe they sized it wrong or after install. they did not tweak the system well. I am a retired EE from Honeywell, not an expert on HVAC. Good luck.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tony, it happened after the new furnace, but not immediately after. It mus t have been about 2 months later, which is why I do not hold the hvac compa ny responsible. I wish they would give me some curb side advice, but I thi nk they want out altogether. They don't return phone calls, and so on.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

arch on filters and get ones that allow the maximum air flow, and I'll repo rt back In a day or two to tell you if it helps or not.  I still don't se e what I can do if it is a balance problem.  Is there a away of fixing th at?  Who do I call to look into it?

The problem with the pressure theory is that Dom reported yesterday that the problem doesn't occur when he turns on just the fan. The fan setting on these systems is typically a higher speed than heating at first stage or second stage. It's almost certainly moving more air with fan only and would go through the same pressure range or higher. Dom can verify that by checking the airflow and sound from the blower. If it's making noises with first and second stage heat and not with "fan only", I don't see how it can be a pressure problem.
Dom didn't give a time from when the blower starts to ramp up until the noise occurs. If it's after the blower has already been at full speed for 10 secs or more, I think it would strongly suggest that it;s heat related.
Another simple test that could be performed would be to start up the AC and see what happens at the highest speed. It's too cold out, but it can still easily be done. Just open the circuit breaker for the outside AC unit. The furnace blower will still run, but the compressor won't start. See what that produces. That will have the blower at it's highest speed, max pressure.
One other question comes to mind though. Has anything else changed in the house? Basement been finished? Some registers closed? Did he check to make sure nothing has been placed in front of a register or return, blocking it? Room doors shut that were previously opened? Most or all of that shouldn't cause it to make noises if it was properly secured to begin with. But if a section of duct isn't installed correctly, those things could be what creates the conditions to make the noise happen, at least if pressure is a factor.
And in the end, it most likely doesn't matter, because the ducts are supposed to be installed so that they don't move. Fixing that is probably the only thing that is going to produce a solution.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

search on filters and get ones that allow the maximum air flow, and I'll re port back In a day or two to tell you if it helps or not.  I still don't see what I can do if it is a balance problem.  Is there a away of fixing that?  Who do I call to look into it?

And I think that nails it. Terrific. My next step is to remove the sheet rock under the duct that causes the damn shot-gun level clanging, do whatever I need to do to stop it (possibly getting a duct pro to replace it), then fix the sheet rock. Thanks. I feel confident going into this.
Dom
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

research on filters and get ones that allow the maximum air flow, and I'll report back In a day or two to tell you if it helps or not.  I still don' t see what I can do if it is a balance problem.  Is there a away of fixin g that?  Who do I call to look into it?

I'd do the AC blower test first, just for the hell of it. It's kind of mandatory to do that before you close up the drywall again, anyway. You need to make sure there is no more banging with AC too. And it takes 5 mins to open the breaker for the outside AC unit and turn the AC on via the thermostat.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

e research on filters and get ones that allow the maximum air flow, and I'l l report back In a day or two to tell you if it helps or not.  I still do n't see what I can do if it is a balance problem.  Is there a away of fix ing that?  Who do I call to look into it?

e.

or

Hmmmm. I didn't know that, but its a good idea. Maybe I just won't close the drywall until it is possible to turn on the AC in a few months. I really don't want to fool with the breaker. I don't know what I'm doing out there.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

ome research on filters and get ones that allow the maximum air flow, and I 'll report back In a day or two to tell you if it helps or not.  I still don't see what I can do if it is a balance problem.  Is there a away of f ixing that?  Who do I call to look into it?

ace.

g or

k.

t

You most likely don't have to go out there. Unless your circuit breaker panel is outdoors. If it's inside, all you have to do is find the breaker for the AC and turn it off. It should be labeled and it will be a double one, 30 to 50 amps. You just turn it off like any other breaker. The furnace and it's blower run off a seperate circuit/breaker that serves the furnace.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

t>

some research on filters and get ones that allow the maximum air flow, and I'll report back In a day or two to tell you if it helps or not.  I stil l don't see what I can do if it is a balance problem.  Is there a away of fixing that?  Who do I call to look into it?

rnace.

ong or

uck.

he

uct

t

w

Okay, I misunderstood. I thought I had to uncover a circuit breaker at the AC unit (told you I don't know what I'm doing here). So I turn it off at the circuit breaker panel -- can do. Then I turn on the thermostat to AC? Sounds like with the breaker off, nothing will happen at the thermostat, but I can always give it a shot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

net>

do some research on filters and get ones that allow the maximum air flow, a nd I'll report back In a day or two to tell you if it helps or not.  I st ill don't see what I can do if it is a balance problem.  Is there a away of fixing that?  Who do I call to look into it?

furnace.

wrong or

luck.

the

duct

n't

now

d

The double pole breaker that goes to the AC unit only powers the outside unit, ie compressor. The furnace has two low voltage wires that go to the outside unit that switch it on. So, when you turn off the AC breaker, the furnace still has AC power via it's own totally seperate circuit. Selecting AC and lowering the thermostat will result in the furnace blower going on and it sending a signal to the AC outside to start up. With no power to the AC, all you'll get is the funace blower running at AC speed, ie highest speed.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Where are you located, a 95,000 BTU input gas furnace is huge unless your house has no insulation, is also huge, or way up north. I have a large house in Canada, and my furnace is 2/3 the size of yours.
You may have too much pressure, but also why is your furnace going into the second stage all the time, this is normally used when it is very cold outside and stage one cannot keep up.
With the blower on full and the heat on second stage, your old air ducts may not be able to handle the extremes and be oil-canning. How old are your ducts, old ones were made of heavier metal, and should be able to handle the new equipment. You don't want a "handyman" messing with your ducts, he may be good to drop the drywall but get a good sheet metal duct installer to fix/replace your problem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I

use

95,000 isn't so huge.. They make them up to 120K, which is what I have here in NJ in a 3100 sq ft house. The one it replaced was 150K. A 100K would be OK too, but 120 warms the house up faster if you have it set back and come home early, which is nice.

he

Did he say it's going to 2nd stage all the time? Typically most two stage are going to go to 2nd stage if it's recovering or you move the themostat higher. If it's just maintaining, then first stage is usually enough.

may

Even on full, the blower in heat mode is moving only about 60% of the air that the same blower would move in AC. I asked if he had AC and what happens with that on or just fan only weeks ago, but I don't think it was answered. That would go a long way toward figuring out if it;s a temp expansion noise or the duct flexing from air pressure.
How old are your

the

A new furnace isn't putting any unusual demands on the ducts. The air moved is about the same as a 30 year old furnace.
You don't want a "handyman" messing with your ducts, he may

I'd say if you can see it flex and figure out where to brace it so it doesn't move, no reason anyone can't do it.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 3/25/2013 11:51 AM, Dom wrote:

Can you gain access to either of the two ducts? If so, see if they have the crease that goes from one corner of the duct to the opposite corner. These are there to strengthen the sheet metal and prevent what you are hearing.
Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I

I can't acces it except through the vent. I need to remove the sheet rock, and I'd rather go through a home improvement guy for that.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

) I

.

.

oted text -

Just make sure you have everything in writing, including the cost and don't get hosed by a home improvement guy.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

.

y

ry

at

f

2) I

wn.

I

r

he

ve

er.

e

quoted text -

Trader4, thanks for the info. You actually remembered me from my last post? Wow. You're right on a few points -- no, 95k is not too large at all, others around here (I'm in central jersey) have more, but I did some research and I figured for my size home anything larger would cycle too frequently. And no, I did not say I go into second stage. Usually it is only the first stage, and I have it set so it stays there for 12 (max) minutes.
I never did the fan only test because my thermostat does not have that setting. Don't know why. I'm going to assume it is temp, and not air pressure, because, like I said, the hvac company is very reputable, and three other reputable companies tried to sell the same system.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

ht.

dry

dry

that

of

).

s, 2) I

down.

nd I

her

the

have

rner.

are

et

e quoted text -

r

Why did I say central jersey? I'm in south jersey.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dom wrote:

Me too -- Camden County.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.