Pee-ew, My Air Conditioning System Stinks (literally)
I have a brand new central air conditioning system that was installed in my house last year. My house was built in 1910 and never had air conditioning before. I have a dual A/C system with a high velocity (small duct) system for the second and third floors and a standard Carrier A/C system located in the basement that cools only the first floor.
The basement has stone walls and is unfinished. Some areas of the floor have damp spots. The floor is poured concrete that has not been painted.
I purchased a new A/C filter before I started using the first floor A/C system two weeks ago. When I turned on the first floor A/C, I noticed that the air blowing from the vents makes the first floor smell and feel like the basement- damp and musty.
Before I realized that there might be something wrong with the system, I took a scented gel sheet (lilacs) into the basement to mount onto the A/C filter to get rid of the odor and so that the first floor would smell like lilacs. However, I did not know which side of the filter was the intake/outlet so that I could place the gel sheet correctly. So, I left the gel sheet on a table in the basement next to the A/C/unit (which was on). I went to the second floor of my house to get the A/C instruction manual to identify the intake/outlet, so that I could place the gel sheet on the correct side of the filter.
When I returned to the first floor, the whole floor smelled like lilacs, and I did not even install the gel sheet. Therefore, it seems to me that the A/C unit is drawing air from the basement. I then thought that the A/C unit was supposed to draw air from the outside.
I called the A/C installer and he came to my house. He checked the ductwork in the basement to make sure that it was securely taped at the joints. He could find no openings where basement air would enter the A/C system. I asked him where the outside air intake was for the system. He told me that I have a "closed system" and that air is re-circulated from the first floor through the return vents to the A/C unit and that air is not brought in to the unit from outside. He also said that if air was brought in from the outside, on a very hot day the A/C unit would have to work much harder to cool the air.
Also, the A/C unit does not seem to help dry out the humidity in the basement because the floor has damp spots.
I have two questions:
(1) How is the basement smell getting into my air conditioner?
(2) How do I get my air conditioner to stop sending damp and musty air to my first floor?