[miamicuse]

There is a section of my attic that I need to get to in order to do some electrical wiring.


Unfortunately there are three junction boxes with over a dozen wires leading to them and out of them, are sitting right underneath a central AC duct, and there is no room to move in any direction to shift the duct out of the way.


Here are some pictures, there are two ducts that came an air handler about 20 feet away, and then one turns left and one turns right.

The duct to the right [with the red arrow] is the one that is in my way. I need to access the three junction boxes below it inside the joist bay, and I need to crawl across the space currently occupied by the duct to get to a wall about 4' away.


Following the duct further to the right it is connected to a plunum with a supply vent.

Is there an easy way to disconnect the duct temporarily and push it back 5 or 6 feet to get it out of the way, so I can do what I need to do there, then connect it back later? If so what is the best location to do it? Do I disconnect it where it ties into the plunum? or do I just use a razor blade to cut the actual duct in two then join them back later with some connector?


You might wonder why not just open a hole in the ceiling directly below that spot so I can work on whatever I need to from below? This is because the spot is in a kitchen and directly below are tall wood cabinets that runs from the floor to about 4" below the ceiling.

 

[surferdude2]

Take it loose from the plenum and add a short piece of rigid duct to extend the take-off collar so you can reroute the flex out of the way permanently.

 

[miamicuse]

The insulation duct's foil is taped to the plenum with aluminum tape all around, then more aluminum tape is all over the entire plenum overlapping all the corners. If I remove the tape it might tear all over. Should I just use a razor blade to cut around the outside of the duct where it joints the plenum?

 

[surferdude2]

Yes, you need to remove all that foil tape that is around the start collar and then you will likely find a zip tie holding the flex core onto the start collar... cut that off too.. then there may also be a sheet metal screw holding the spiral wire of the flex to the collar... remove it if so.

Screw the new duct entension onto the collar (3-points equal spaced) and support it as necessary so it doesn't pull the start collar loose from the plenum. Then reattach the flex duct to the extension using the screw, zip tie and either duct tape or foil tape.

I use the tape on the inside joint where the flex plastic core joins the collar rather than taping the outside and used the zip tie for the outside but it's a different strokes for different folks thing I suppose.

 

[miamicuse]

I cut the tape around the duct where it connects to the plenum. Boy that was fun, no head room at all and I can only touch but not see the far side, I was able to remove the tape and tease back the insulation to expose the flex duct, but that seems to have a hard plastic collar around it. I felt around it and didn't see any screw. It has tape around that too, not sure if I should peel back that tape as well? I had to get out to breath, disturbing all that insulation I started coughing. May be I should be wearing a respirator, but the attic is 100 degrees in South Florida now.

 

[surferdude2]

Yes, wear a mask... and remove the remaining tape that is holding the duct to the collar.

It's too bad you can't get the guy who installed that flex over a junction box to show him what for.

Attic work and crawl space work makes you wonder if you chose the wrong trade. The only good part is, it makes cold beer taste better than ever. :smile: