Replies

1. 
   Riversong | Jan 14, 2011 11:15am | #1

   Take the dirty socks off the return register.

   Could you be more specific about what you mean by "dirty sock syndrome"? Is it a musty smell?

   It could be that the new unit is moving air at a higher velocity and picking up existing debris in the ducts (were the ducts cleaned?). You might also try disconnecting the UV lights to see if that makes a difference.

2. 
   user-696154 | Jan 21, 2011 08:44am | #2

   His AC contractor disabled the UV lights. That made no difference.

   The smell occurs when switching from heating to cooling and lasts for 2 weeks. If he has to heat, it goes away--then returns when the unit switches to cooling.

   The fan is sized the same.

3. 
   BobHr | Jan 21, 2011 01:04pm | #3

   It seems strange that he has a problem at switch over plus 2 weeks is a long time. the smell at the start of the heating season is normally from the dust buildup on the heat exchanger being burned off. That usually goes a way after a day or 2.

   What type of UV system did he have. There was, don't now if it is still made, a system by Trane or Carrier that has a 4 inch filter, 6 UV light bulbs and a catalyst. I ran across one at a customers house. A quick look at the manual showed that the UV lights did not kill germs, virus, etc. The filter/light/catalyst was to filter and stop odors. It required that the lights and catalyst get replaced each year. Oh and the lights looked light short florescent lights.

   Then there is a UVC light. The C part of the UV spectrum kills small living organisms in the air like viruses, bacteria etc. It will kill mold spores that get by a filter. If it is mounted above the A coil it will help keep the A coil and pan free of growing organisms. UVC lights have an effective life of about 12 months. They will still produce light but UVC light output diminishes and then they are no longer effective.

   You said the AC and furnace were replaced but was the A coil replaced.

   I would suspect there is something in the drain pan for the A coil. When AC season starts it gets wet and gives off an odor for a while. Later when the AC if off and the furnace starts operating the drying of the debris in the A coil pan smells.

   I would also look for signs of water that has leaked into the furnace.

   I should have asked if the furnace in a crawl space or an area that has a lot of humidity. Does the duct work sweat.

   No other part of the system should be wet. It takes moisture for something to grow or rot.

4. 
   user-696154 | Jan 21, 2011 06:16pm | #4

   Thanks for your input.

   There is no crawlspace. The units are in closets at floor level. One serves the upstairs, the problem unit the downstairs.

   I haven't looked at it yet. I asked him to call me the next time it happens.

   If anyone else has a flash of brilliance, please add to this thread.

   Thanks,
   Wynn