Embodiments of the invention provide a pumping system and method including a flow locking feature. A pump controller includes a user interface configured to initially receive and set a plurality of programmed flow rate settings, a maximum locked flow rate, and a minimum locked flow rate. The pump controller is also configured to disable resetting of the maximum flow rate and the minimum flow rate once they are initially received and set and to allow resetting of the plurality of programmed flow rate settings throughout operation of the pumping system. The pump controller is further configured to operate a pump motor in order to maintain a first flow rate set by one of the plurality of programmed flow rate settings as long as the first flow rate is between the minimum locked flow rate and the maximum locked flow rate.
