Trace duct from upstairs to down?

[ManCave]

We have a 2 story home with a couple of bedrooms upstairs. I want to find where the duct work goes from the basement to the upstairs room. I can see by looking inside the duct in the upstairs bedroom that the duct travels between the floor joists from the front of the home towards the back. Bedrooms are in the front.

Any suggestion on how to locate where that duct attaches to in the basement? Should I try an run a snake through it? I think it unlikely the snake would make whatever turns are necessary as at some point it has to 90 degree down.

I know I'm not the first to run into this so thought I'd ask in case someone has an option I should consider. Thanks!

 

[The Cobbler]

why do you need to trace it?
you should be able to see where it comes off the main duct in the basement, then up thru the stud walls. from there it will be between the joists and run to the vent opening. probably more or less in a straight line, but it could be in a bulkhead to cross joists too

 

[ManCave]

The home is 7,000 sq feet. There is no way from the basement to look at a duct and figure out where it goes.

I need to temporarily install a booster fan (before Friday) to push more A/C upstairs. The permanent fix is we're installing ductless air/heat in those rooms but can't get it done before Friday so for now hoping boosting the air flow will help cool that room.

 

[The Cobbler]

how about lay a box fan over the vent and take a lighter to the joints in the basement to see if you can see the flame blow, or failing that separate the ducts in the basement to feel the air flow .
blow heated air down the vent (hair drier) and feel what duct gets warm?

 

[the gypsy]

Did you think, to use a thermal imaging gun. This may help IMHO.

 

[OccupantRJ]

There are booster fans that go in place of the register in the room if you want a quick solution.

 

[mrobins297aaa]

something similar to what cobbler said, why not narrow it down to the ones you think it maybe and put the fan switch on the thermostat on the "on" position and then get someone to close the dampers on each run out one at a time and see if the airflow to the register your having a problem with stops flowing air.
That's of course you at least some air flow to begin with

 

[the gypsy]

rent a camera similar to a plumbing camera to trace your duct.

 

[brewchief]

Put a radio or alarm clock on the register, you can normally hear it pretty good in the basement through the duct

Sent from my XT1254 using Tapatalk

 

[larry4406]

Don't drop an alarm clock down it like the idiot on TV

 

[Todd.Brock]

Our west wing is about the same size and it was hot once... just once.

All kidding aside, it sounds like you have a specific need for a cool room on Friday for a visitor or whatever. If so, can you maybe rent a small A/c unit? They make a version that vents to the outside , but doesn't actually sit in the window.
My buddy used a booster fan for a room he was having cooling issues, and it wasn't much more comfortable after cutting in the booster, wiring, etc.
Just a thought.

This is what I was thinking of. They work, but they are a little loud.

 

[eddieK]

The booster fan is not going to provide enough air to make a difference, especially after the work/cost involved.

 

[zmaxmotorsports]

Have you tried closing vents in other rooms?