Final Attempt at Finding a Solution!

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rockncountry101
Posts: 79
Joined: Sun Mar 11, 2012 3:56 pm

Tue Dec 17, 2013 2:40 pm

My house is almost two years old. Since I moved in I have been plagued with noisy ducts underneath. When I turn the unit on I hear constant popping coming from the unit. After the air or heat goes off I hear constant knocking underneath from the unit to about 20 feet away in one direction. Stepping over it causes it to do it too. However, it will continue to do so regardless if I walk on it and it does it for a very long time. I keep hearing people say that it's expansion and contraction. I tried an experiment where I would leave the fan running for five minutes after the heat or cool kicked off. Now if it was expansion and contraction you would think that that would be enough to cool it off beyond the need to pop and snap. It has driven me to the point where I was willing to have the ducts replaced. No one will do it. They tell me that either the insulation won't go back up right or they tell me that I wouldn't be happy with flex ducting because of critters. This house is only 56' long and the ducts are one straight line with no branches. How hard could it be? It's either hard or they don't want to do it. I have come to a crossroads. I either get this fixed or I have to get window units and space heaters. I don't know if the unit is oversized or if there is a pressure problem or what exactly and I have run out of options. I ask that if anyone knows of anything that can be done to please help me out. I can't sleep in my bedroom because of it. And two years is a long time to be going out of my mind. The dealer that sold me the house told me that it did this is 50% of the houses but I haven't talked to anyone else that has the problem.


calderhill
Posts: 51
Joined: Sat Aug 17, 2013 1:37 pm
Location: Oneonta, NY

Tue Dec 17, 2013 4:12 pm

You just described my trailer to a "T" :mrgreen:

It is expansion and contraction.

It was -3F this morning.

Can you hear it?

Maybe yours is louder than mine as it doesn't bother me at all.

Replacing the ductwork is not hard but a major destruction of the trailer in the process and it may not solve your problem due to other factors.

Hopefully others will chime in.

rockncountry101
Posts: 79
Joined: Sun Mar 11, 2012 3:56 pm

Tue Dec 17, 2013 4:23 pm

Yes I can hear it...all night long. Every night. For two years.

rockncountry101
Posts: 79
Joined: Sun Mar 11, 2012 3:56 pm

Tue Dec 17, 2013 4:24 pm

What other factors are you referring to? My problem is only in my bedroom. I very rarely hear it in the rest of the house.

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Greg
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Joined: Wed Feb 28, 2007 8:01 pm
Location: Weedsport, NY
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Tue Dec 17, 2013 7:41 pm

Still fighting with it I see. This is not the best time of year to be messing with ducts, but I do understand your frustration. As calderhill said it should not be a real tough job, but it will take a little time. You can carefully cut the belly in few areas to get access to the ducts. If you are changing them out go with a heavier metal than the foil that is most likely there now.

Since you have let the fan run past the normal cool down, I almost question if the ducts are "Ballooning" with pressure from the fan.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."


terrifromohio
Posts: 76
Joined: Thu Aug 20, 2009 9:31 pm
Location: United States
Contact:

Wed Dec 18, 2013 9:27 am

I have the same exact problem. I even searched the internet because I thought something was wrong underneath the trailer. So I guess this is a common problem. Yes I too have a hard time sleeping because of all the popping and crackling, I can`t stand it either.
I have a 14 by 70 which also is just straight ducts all the way through the trailer, maybe that is some of the problems.
I lived in a doublewide prior to this and never had this problem.

calderhill
Posts: 51
Joined: Sat Aug 17, 2013 1:37 pm
Location: Oneonta, NY

Wed Dec 18, 2013 12:44 pm

It's too bad I can't put up some audio for you.

Being near zero, the furnace comes on pretty often in my 14x70, '70's.

I have the straight through from front to back and it is standard metal ductwork.

It's easy for me to see that the ductwork, especially nearest the furnace will get hot enough to expand and rub against everything it touches, which is a whole bunch.

Having hot air systems in other conventional homes, I seem to recall like noises but not as dramatic.

What I meant was the new ductwork, unless it's isolated from where it's attched, might have the same problem or just the metal joints rubbing on themselves.

Ahhhhhhhh, it's creaking at me right now. :lol:

Maybe it's the 4 years I spent in the USN, listening and feeling the engine at flank speed, cruising the Atlantic.

rockncountry101
Posts: 79
Joined: Sun Mar 11, 2012 3:56 pm

Wed Dec 18, 2013 4:45 pm

Does your's also do it in the summer when the a/c is running? Mine is just as loud when the a/c kicks off in warm months. That is crazy.

rockncountry101
Posts: 79
Joined: Sun Mar 11, 2012 3:56 pm

Wed Dec 18, 2013 4:49 pm

I also slowed the blower speed down and it still done it. I did notice that the btu rating on the furnace is higher than the max allowed on the data plate of the home.

countrydan
Posts: 82
Joined: Fri Apr 19, 2013 3:51 pm
Location: s/w michigan

Wed Dec 18, 2013 9:01 pm

rockncountry101 wrote:I also slowed the blower speed down and it still done it. I did notice that the btu rating on the furnace is higher than the max allowed on the data plate of the home.

based on the data plate info and your unit I would guess the cfm and btu are not helping the situation. Verify your fresh air, exhaust and ducting is proper for your bigger unit first of all IMO. Then, can you pinpoint the noises to an area? A possible try I might do would be to install angled L pieces to the flat ducts if they are popping. But you would need to open the belly material and expose the ducting. When its nice out it wouldn't be the end of the world..

DaleM
Posts: 385
Joined: Wed Apr 07, 2010 10:07 am

Sun Dec 29, 2013 10:09 am

One thing you can try is to open the belly wrap and relieve the tension on the straps holding your ductwork up to the floor joists. Loosen them in a way to allow the duct to float lower in the straps and not contact the wooden joists. That's normally where the noise is created when it's the popping type from duct expansion and contraction that last several minutes. Noise from a duct expanding from excess airflow usually doesn't last after the blower is on or off but for a few seconds.

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