Originally Posted By: anatol polillo This post was automatically imported from our archived forum.
Fellow Inspectors,
Had an inspection today. Forced hot air/cooling system. The hot water heater and furnace were in an enclosed room in the basement. There was an open duct terminating over the waterheater. When the furnace was blowing, there was no flow I could detect. No idea if it was a return or supply duct. If it is a return, it is way to close, in my opinoin to the water heater and furnace. Lack of flow makes me feel it is not a supply.
I wrote it up as a possible hazard if it is a return duct. Any other ideas???
Also, the exaust fan was turning when the furnace was not firing. It was not on, just freewheeling, and counter to the direction it turns when the furnace is on. Is this an example of backdraft?
Originally Posted By: ekartal This post was automatically imported from our archived forum.
Hi Anatol,
I'll have to keep on reading this one myself. But how tight is the enclosed room? Perhaps that's a combustible air duct. The combustible air required cannot come from the room itself.
Originally Posted By: Susan This post was automatically imported from our archived forum.
Anatol,
Sounds like a combustion air duct that was possibly run to the attic...
If that is the case, you would want to make sure that insulation was not blocking the end of the duct and that the duct terminates well above the insulation (especially blown in). On this type of set up there should not be any type of cover or screen over the end of the duct. And finally, you would want to make sure there is adequate ventilation in the attic.
Originally Posted By: rsummers This post was automatically imported from our archived forum.
I agree it was most likely a make up air duct. You would usually see a screen Covering the opening but not always. I make sure they are not blocked off with insulation if I can access the area.
Originally Posted By: anatol polillo This post was automatically imported from our archived forum.
Thanks for the thoughts. The duct was not covered. I was not able to track the duct all the way to the attic. When I was in the attic there was no way to see the other end. Very confined sloping crawl space. Yes the water heater was in a confined space. So it is probably a combustion air inlet.