The furnace is mid efficiency. Located under staircase,enclosed with slotted door to lower family room. Next to the door is a return vent located at the bottom of the wall and ties directly to the bottom of the return ductwork at furnace. Any problem with this vent location?
Is it within 10 feet of the burners?
Not really. It could have been put in a better location. But it should have adequate combustion air.