This device was humming at the inspection. It doesn’t seem to be attached to the HVAC system. It seems to have a vent to the outside (the picture with the brick). Thermal imaging showed it as warm.
Anyone know what it could be?
1 Like
You have any better shots or close-ups?
(And FWIW, let folks know where you’re located, what type of equipment, etc.etc.)
Hello, friends. The combustion duct didn’t seem to connect to this thing.
This is in Provo, Utah.
It might have bring in air. But there is already plenty of combustion air…
WAG’s:
Duct booster?
Down-draft vent?
HRV unit?
1 Like
My WAG Makeup air? 
3 Likes
That’s what I was thinking.
Is the kitchen above?
1 Like
Me as well
1 Like
Debris/Dust buildup
The dust, dirt, or debris accumulation within the ductwork can also lead to whistling or flapping noise as air passes through. These particles can obstruct or cause vibrations, rattling, or buzzing sounds.
1 Like
These are great insights. Why would a down draft vent be used in a basement?
It wouldn’t be “used in the basement".
But it would pass through the basement to exhaust at the exterior, at least the type I was thinking of.
That’s why I asked if the kitchen was above…particularly the range.
The kitchen isn’t above this vent
Did you crawl in the crawlspace/basement?
It looks as if the 2nd image is a crawlspace vent in a facade of masonry. Perhaps it was a vent fan that is set to regulate humidity and force air flow to keep things dry. I have seen this in crawlspaces before where the water table is exceptionally low and the occupants have had to add in a crawlspace vent that is humidity controlled and will fluctuate as needed to circulate air beyond the passive air flow…Possible
Secondary Guess - The image you have of the HVAC system could also be as a secondary set up could be combustion air flow being sucked in if the furnace was in an airtight enclosure.
Thirdly - what is up with that drywall work?! Looks as if someone tried it out blindfolded.
1 Like
You first…
Elaborate / Identify what is located between the furnace and the wall that uses a flue?
(Marked with ??? in pic below). Water Heater is on left in pic.
Great insights here! I appreciate the help.
The drywall work is, indeed, horrible.
Two furnaces. One with ac and one without.
On the right is a central vac
With that information, my WAG (without being on-site to investigate further and knowing the full layout of the structure) would be a booster fan such as mentioned above.
1 Like