Need an ingenious way to find something in the wall

signal15,

Where are the supply and return vents / ducts in the room. You mention removing drywall in the ceiling? Do they come from below or above? How does the fan get its power? If you could shut on / off the power supply and maybe use a stethoscope / glass/plastic cup you might be able to hear hum from a relay or motor.
 
signal15,

Where are the supply and return vents / ducts in the room. You mention removing drywall in the ceiling? Do they come from below or above? How does the fan get its power? If you could shut on / off the power supply and maybe use a stethoscope / glass/plastic cup you might be able to hear hum from a relay or motor.

Supply ducts are on the floor below the outer walls, return ducts are on an inner wall. I think the fan is under the floor near the inner wall.

The problem is, the fan is not working at all anymore. So I cannot track it down by sound/flipping circuits.
 
Do you have a basement or a crawlspace? Is the electric in conduit?

If the motor on the fan burned up then you might be still able to hear a hum. You can use an amp probe to see if its still drawing electric.

If the fan is under the floor how would you get to it?

Many years ago played with a metal detector and different metals would cause different readings (like the windings in the motor might sound different).
 
by deduction, if the room was cold then they added the fan later. Most HVAC guys don't install duct fans as part of the base system; their airflow calculations are based on a single blower located at the air handler. So, how was the ductwork accessed later to install this fan? I'd consider the entire supply branch for the room then concentrate my search in most accessible spot. If remodeling occurred after the fan was installed then this method might not be effective.
 
by deduction, if the room was cold then they added the fan later. Most HVAC guys don't install duct fans as part of the base system; their airflow calculations are based on a single blower located at the air handler. So, how was the ductwork accessed later to install this fan? I'd consider the entire supply branch for the room then concentrate my search in most accessible spot. If remodeling occurred after the fan was installed then this method might not be effective.

I think I know where it is, I just want a way to be more sure before I start tearing things apart. The guy was living in the house as he built it, so who knows at what point he added the fan or how he went about it.
 
Did anybody say stud finder?
They work pretty much, I think, on measuring the density inside the wall. I know that mine works differently on an open cavity framed wall vs. a wall stuffed with insulation vs. a wall on furred concrete. They also detect live wiring behind the wall fairly well.

Sonny
 
Home inspection companies have heat sensitive "cameras" that are mainly used to detect if any insulation is damaged, etc... behind walls. I had one in my home (builder provided) as there was a question if insulation was in all of my walls (long story) and was amazed at the details provided by this camera. Maybe call one up and see if it's feasible and cost effective.
 
Home inspection companies have heat sensitive "cameras" that are mainly used to detect if any insulation is damaged, etc... behind walls. I had one in my home (builder provided) as there was a question if insulation was in all of my walls (long story) and was amazed at the details provided by this camera. Maybe call one up and see if it's feasible and cost effective.

I've actually been trying to track someone down that has one (that doesn't want to charge me $500 to come out with it), or some place that rents them locally. The places online that rent them want $700 for a week. For $2k, I could buy a cheap one, and resell it used and only lose a couple hundred bucks max. I would love to get my hands on one of these, I need to track down an insulation problem also, and figure out where the tubing was run in the concrete for my floor heat to see if it's possible to put in a drain for a future wet bar.

I found an old one from the early 80's on Ebay last year that went for like $150. It supposedly worked perfect, but the old ones had to be filled with liquid nitrogen every time you used them to cool the LWIR sensor thingy.
 
I found one place in town that rents them. They are $250/day. Or, I could get someone out here for less money and have them look at it for me.

The other thought is that I might just buy a camera, use it for however long I need to, then sell it on Ebay when I'm done with it. I found some Extech cams for $1995.
 
Back
Top