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Old 12-05-2011, 10:51 AM   #1
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Old flex duct question

Hi, I was up in my attic working on some other things when I noticed the old flexible duct had separated at a couple connections. It looks like the old owners moved a vent and instead of reconnecting the duct sections together they just left them apart.

As a temp fix I went and got some sections of duct and attached to either end of the old duct so now at least I'm not heating/cooling the attic.

But I noticed when I was putting it together that the old duct seems to just be spiraled heavy guage wire like a slinky, just surrounded by insualation. I didn't see any inner core of metal or plastic or anything, just the wire and insulation, then on the outside it's grey plastic surrounding it all.

So my question is, is this ok? The house was built in '76 and I live in Southern California. Seems to me I might be pushing insulation fibers throughout the house because of this, but not sure if this is some special duct that is ok or should I be worried?

Thanks for any advice.


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Old 12-05-2011, 11:43 AM   #2
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might want to consider getting the lenghts with the plastic liner inside the slinky and the insulation between that and the gray plastic.if it is raw insulation and air moving sure you can send fibers into the air.on any suply ducting you want it a straight as possible with minimal turns bends to the register....make sure that return is sealed just as good if the attic isn't heated...need to return the space air not a cooler attic.then if the air handler is laying on the attic floor you need to check completey aroung the connection to the furnace especially that supply/discharge installers just duct tape it completely around and the bottom always dries out and you end up flapping air our into the attic


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Old 12-05-2011, 12:04 PM   #3
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Thanks for the advice. It's a single story, so the return air doesn't go through any ducting as the handler is just in a closet with a vent in the wall.

There's "duck" tape all over the place, so I replaced with foil tape any where I could where there's metal to metal connections, plus a couple machine screws.

How much of an emergency would you think taking care of that raw insulation would be? I'll probably replace the old ducting when I can, but there are a lot of other more pressing issues in this house I need to take care of.

Do you think it's something that should be taken care of eventually and I can put it off for now, or is it something that's very detrimental to health and I should take care of it right away?

Being in SoCal heating and cooling is less of an issue than other locations so I'm only mildly concerned about leakage, and can deal with it for now as I take care of other problems, I'm more worried about air quality at the moment.

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Old 12-05-2011, 12:37 PM   #4
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Depending on how handy you are, I think that replacing your flex is about as logical as any DIY HVAC repair. Upgrade to new R8 flex. It will have a liner, and be better insulated. If you do the work yourself it will not be terribly expensive. If you are worried about fiberglass particles/indoor air quality I would replace the flex now.
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