Unscrew the nozzle cap (1) from the nozzle body (3). This is best accomplished while the retaining nut (2) is securely fastened to the elbow (5). Next, unscrew the retaining nut (2). Push the nozzle body (3) out of the retaining nut (2). The filter (4) will come out with the body. To re-install the nozzle, reverse the above instructions.