The Yale hydraulic door closer is a staple in many offices. The closer shuts the door automatically when you let go of the door. The tension feel when opening the door is known as back check. The back check prevents the door from hitting the adjacent wall when you swing it open. When the back check is out of adjustment, it makes the door seem heavy and difficult to open.
Ask your helper to stand outside the door while you adjust the closer from inside. This prevents people from opening the door while you are working.
Position a stepladder under the Yale closer. Locate the back check valve on the bottom of the closer, between the arm and the door jamb. The valve is an Allen head screw.
Insert an Allen wrench into the back check valve, and turn the valve clockwise to increase the tension. To decrease the tension, turn the valve counterclockwise. Turn the valve in half turn increments at a time.
Move the ladder out of the way and test the door. Continue making adjustments as necessary.