Insulated cross-over flex duct

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Norm
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Joined: Mon Jul 13, 2009 9:35 am
Location: SW Michigan

The home I bought had been sitting empty for a few years and the skirting is in need of replacement. - From that, a critter apparently ripped into the flex duct directly under the furnace.

The only duct I've had the pleasure of working on until now was rigid, boxed stuff for stick-built homes.

Is insulated flex duct measured by diameter?

Also, how do you "splice" in a new section? - Peel back the insulation, duct tape the inner cores together then tape the insulated exterior?

Thanks again!

Norm
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Robert
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Location: Tennessee

Hi Norm,


Moving this to All Other HVAC Questions forum, please follow it there.



Thanks,
Robert
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Robert
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Hi,

Best would be to replace with two 90* ells and straight hard metal duct wrapped with plastic wrapped insulation.


Next would be the same two 90* ells with one section of flex duct stretched tight between them.


I do not advise using flex duct without the ells as it leads to constant problems from mice, sagging, kinks, rips, etc... .



Yes, it is measured by diameter.



Use zip ties, sheet metal screws and foil backed tape to connect and seal joints and seams.


Support it every 4 to 6 feet with web strapping.



Thanks,
Robert
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Norm
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Joined: Mon Jul 13, 2009 9:35 am
Location: SW Michigan

Thanks Robert and sorry about replying to that A/C thread a while back. - Didn't realize it was a moderated forum that way..

It took me a minute to picture what you meant but I think I understand now.. - I was in the frame of mind to just replace the small section a critter tore out but from what you're saying it sounds like replacing the entire section is the better way to go.

As luck would have it, its in an area with a lot of other gear so I'm not sure if thats possible but I definitely appreciate the advice. - I'll definitely try to go with rigid if possible.

Thanks again,
Norm
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Robert
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Location: Tennessee

Hi Norm


You're very welcome and no apologies needed on the reply in hvac forum.


When there are piers, pipes, etc in the way, flex duct may be necessary, but use as little as possible.


Main thing is the two 90* ells which keeps it straight and if pulled tight it won't sag/kink.

Forgot to mention that you can wrap flex duct with chicken wire to protect it from rodents.



Thanks,
Robert
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