Return not connected to the furnace
I have a not air system. My basement (in my one story house plus bedroom loft) is unfinished but I work in it year round. I recently had a HVAC installer redo the duct work because it was not done properly. One return was entirely blocked off. So, when they finished installing the new duct work, both returns were opened but not connected to the furnace. The returns empty out into the basement area. They installed two heat duct grills in the basement and they installed a return grille in the bottom of the furnace. I am disturbed because the first floor returns have not been connected by any duct work back to the furnace. Today the HVAC workers came and decided to block off one of the two returns on the first floor. They did not think that the second return form the first floor should return by duct work to the furnace but should continue to empty into the basement. Please give me some advice here about what is right and what is wrong about this arrangement.