When servicing hvacr equipment, technicians are sometimes required to increase the airflow of a system. This may be necessary in order to correct some type of system problem or to achieve the designed airflow upon start-up.
An easy method for increasing airflow on a centrifugal blower application is to increase the rpm of the drive motor. There is a direct relationship between the rpm of the motor and the cfm of airflow delivered by the fan system. If you increase the fan’s rpm by 10%, you increase the cfm delivered by 10%.