Your new AC came with a filter dryer already installed in the unit your installer added another one when hooking up the unit will this hurt anything?

If the new AC installer put in a filter dryer when there was already one installed it is possible that the installer thought it might need two dryer filters. But, there is a caution here if the unit does not actually now have two filter dryers, it could mean that the installer was trying to cheat the home owner. It is also possible that the factory installed filter dryer was not big enough to handle the AC needs of the home owner.