Heating, cooling, ventilating and make-up air equipment; namely, direct fired heating, ventilating, and replacement air equipment for heating indoor air, ventilating indoor air and replacing exhausted indoor air with outside air; steam coil heating, ventilating, and replacement air equipment for heating indoor air, ventilating indoor air, and replacing exhausted indoor air with outside air; hot water coil heating, ventilating, and replacement air equipment for heating indoor air, ventilating ...