Most organs of 114 ranks, such as the Exposition Organ, can easily function with one blower. Indeed, the Exposition Organ was designed to run with one blower. Why two blowers? In its original installation, the organ was housed in Festival Hall where thousands of visitors attended recitals at all hours of the day and evening. Because of the many hours that the organ would be in use, a single blower risked burnout after so many hours of use. Thus, each blower had cool-down time.
In later years, when the Exposition Organ was moved to the Civic Auditorium, a building built for it, the two blowers were stationed in the basement. As the years passed, air leaks in reservoirs and chest often required both blowers to be used especially during recitals when full organ was required.