> Hello. We have had this problem for several years and each year the
> problem gets worse. We have a high velocity a/c system that runs
> completely separate from our heating system. We have a large house, there
> there are two different A/C systems installed. One in the basement and one
> in the attic. The problem is on the 2nd floor with the attic system. The
> upstairs vents, which are many small round circles in the ceiling, blow out
> fowl smelling sewer air. It comes and goes, but 80-90% of the time these
> vents are blowing out smelly sewer gas air. The whole upstairs smells like
> a sewer after a while. Don't know if this is another clue but sometimes
> the air that blows out is on the warmer side, other times it's cold. If
> the sewer smell isn't coming out, then it smells musty and sometimes moldy
> smelling? Hard to describe.
> Another clue? During non summer months when we don't use the air
> conditioning, when it rains heavily, snows heavily, or on windy days, the
> smell comes through the a/c vents.
> PLEASE HELP! I am no longer able to sleep in my bedroom upstairs because
> of the smell. Thank you.
WATER in 'P' trap needed..