Chimney Smoke Sucked Into Makeup Air Unit (MAU)
I live in a twelve unit, four story, apartment style condominium. Each unit has a wood-burning fireplace with the chimneys around the perimeter of the roof. The roof is flat. Also on the roof is a MAU which feeds ventilation air to the hallways in the building. It sits roughly in the middle of the roof.
Occasionally we have a problem where smoke from one of the fireplace chimneys gets sucked into the MAU filling the building with a smoky smell, sometimes quite heavy.
Is this a normal consequence of having fireplace chimneys and an MAU sharing the same roof, or is there something wrong with the chimneys and/or MAU design?