What's That Smell?

Unfortunately, sometimes there are smells in the office that aren't as pleasing as this flower

Something I’ve run into a number of times is an odd (and often foul) odor which will be noticed at the beginning of the day and more often in the springtime. The smell often gets worse when the central vacuum is turned on and the source seems to be in the mechanical room. Many times there is an old disused floor drain which is the actual source of the odor.

As many of you may know, drain lines have a recurve to trap liquids in the line and provide a barrier to vapors coming up from the sewer. Old drains that are no longer used can dry up and lose this liquid barrier. If you have odd smells in your mechanical room, check in the corners, inside cabinets, and at the walls for old drains that are no longer being used. Often these can be safely capped (although you should have a plumber do this to be sure) but you can easily refresh the liquid barrier in the drain. Simply pouring water in will work, but it will evaporate quickly so you’ll need to keep on this regularly. Basic cooking oil makes for a better longer term barrier as it has a very low evaporation rate. About a half cup of oil should be more than enough to serve as a vapor barrier in an old drain.