A method is provided for reprocessing an internal channel of a medical device with a reprocessing system having a valve, a fluid line fluidly coupled with the valve, and at least one sensor coupled with the fluid line. The method includes performing an actuation of the valve to direct liquid through the fluid line and into the internal channel, and detecting with the at least one sensor a predetermined condition within the fluid line while the liquid is being directed into the internal channel. In response to detecting the predetermined condition, a time duration measured from the actuation of the valve is recorded. The method further includes purging the liquid from the internal channel, and directing liquid through the fluid line and into the internal channel for the time duration.