Central Air Conditioning Unit Smell

by Conrad
(New York)

I just had a whole house dehumidifier attached to the return ductwork in my home. When I run the dehumidifier for a time then turn on the central ac unit, I get a damp metallic smell for about five minutes and then it goes away.

If I do not run the dehumidifier before running the central ac unit, there is no smell. The air from the dehumidifier goes through an electrostatic air cleaner before reaching the central ac unit coil area.

Is there any way to eliminate the smell when I run the dehumdifier? Why do you think I get the smell?