Noise in Central Duct AC System

[glendodom]

I have a 2011 36RE with 2 ACs with the central duct system. This weekend during use I started hearing a noise in the rear of the trailer roughly about where the top 15000 unit sits. It sounds like something "flapping" in the duct work. I check it with the AC and fan only which it still makes the noise thus I know it has to be something to do with something flapping. I pulled the return ducts off and can't seem to locate anything. It seems to be in the cold air duct side. After taking off two of the rear cold air duct covers I found small pieces of the ac duct tape, foil type. I am thinking somewhere in the ductwork some foil tape has loosened and is causing the flapping sound.

Other than literally pull the ac unit I don't know how you could ever get to the item making the flapping sound. I can't find anything flexible enough but yet stiff enough to run through the outlet duck opening to attempt to locate it or dislodge it.

Anyone ever run across this issue? or have a suggestion?

Thanks,

[BigJohnD]

Ours did that, or still kind of does. I hadn't got all of mine solved, but it is in fact the foil tape you mentioned, or something along those lines. One little piece will drive you nuts. One of my noises was right where a vent penetrated the duct line. It was right over the bed, so quite irritating. Luckily, I can reach that one, but I hadn't quite got rid of the noise. There is another noise coming from the other duct, but it's a little further up in there at maybe a duct connection. Thinking a piece of tape up in there next will rid of that one.