Openings must be located more than 10 feet measured in any direction from an open combustion chamber or draft hood of another appliance located in the same room or space. - The amount of return air taken from any room or space must not exceed the flow rate of supply air delivered to that room or space. - Return air must not be taken from a closet, bathroom, toilet room, kitchen, garage, mechanical room, boiler room, furnace room, or unconditioned attic.