two thoughts:
1) it sounds like maybe someone has used, or heaven forbid is still using, the vent as an auxilliary litterbox. If one of the cats is peeing in there, or it's got old pee from sometime before, then *that* would be the problem to address. Can you put something down there that would show if it gets peed on? Like tape a piece of paper down real well to the floor of the duct, or something like that. Also if you know anyone who owns one of the UV ('black') lights that's the correct wavelength to make pee stains fluoresce, you might borrow it (although failing to see anything would not *absolutely* convince me that nobody had peed in the vent).
2) is it possible that what you are smelling is as much *damp* as litterbox? We have that problem around our fireplace (big massive stone surround and chimney) on hot days until late summer, and it smells like a peed-on wet dog
After extensive poking and prodding and investigating, it seems to just be from moisture due to condensation (hot humid air hits cool stone, condenses out, and I guess grows mildew or something like that, or maybe the moisture activates old dog smells that have gotten into the stone or the floor adjacent to the stone -- this house has had mucho many dogs in its past). Is it possible that your ductwork might have leaks where warm humid air is coming in and condensing out?
Good luck,
Pat
1) it sounds like maybe someone has used, or heaven forbid is still using, the vent as an auxilliary litterbox. If one of the cats is peeing in there, or it's got old pee from sometime before, then *that* would be the problem to address. Can you put something down there that would show if it gets peed on? Like tape a piece of paper down real well to the floor of the duct, or something like that. Also if you know anyone who owns one of the UV ('black') lights that's the correct wavelength to make pee stains fluoresce, you might borrow it (although failing to see anything would not *absolutely* convince me that nobody had peed in the vent).
2) is it possible that what you are smelling is as much *damp* as litterbox? We have that problem around our fireplace (big massive stone surround and chimney) on hot days until late summer, and it smells like a peed-on wet dog
Good luck,
Pat
