As the door is opened the spring is compressed. During the closing cycle the compressed spring moves the piston toward its original position. This reverses the flow of the hydraulic fluid.

The hydraulic fluid flows as the arrows indicate in the illustration. In all Norton Door Closers there are two points of control in the hydraulic fluid passage in the closing cycle. One point controls sweep speed; the speed of closing short of the last 5 degrees. The other point controls latch speed; the last 5 degrees of closing. Desirable sweep speed is generally a medium-to-low (4 to 6 seconds) closing of the door. Desirable latch speed will vary; a fast speed is desirable for doors with latching hardware; a slower speed is used for doors without latching hardware.

A control valve permits the closing speed to be individually controlled at each passage point. As the piston travels through most of the door's closing, the hydraulic fluid flows through the Sweep Speed passage.

At a point in the door's closing the piston's "sealing collar" closes the passage controlling the Sweep Speed. At this point the fluid begins to flow through the Latch Speed passage only.