- 1). Pull the plastic cover cap off the main lever handle on the faucet, and keep it nearby. Use a screwdriver to loosen and remove the lever handle screw and set it aside. Pull the lever handle off the small spline shaft. Note the chrome sleeve on the handle shaft. Turn the sleeve counterclockwise to remove the sleeve from the shaft, by hand. Use channel locks if the sleeve feels abnormally tight.
- 2). Pull off the chrome cover plate from the shower wall to expose the interior valve body and stem. Look at the stem shaft and the small notched ring that sits on it. To increase the temperature, pull the ring straight out by hand and move the ring clockwise one or two notches. If you wish to reduce the temperature, pull the ring out and turn it one or two notches counterclockwise, and slip it back on the stem.
- 3). Place the chrome cover plate over the opening and screw the collar sleeve back on the stem shaft. Firmly tighten the collar sleeve by hand until you have it in the desired location over the shower wall tiles. Use channel locks to tighten the sleeve, but use only slight force to tighten it.
- 4). Realign the handle lever in the proper position, for the open and close position. Insert the handle screw into the handle bore and tighten it with a screwdriver. Replace the plastic cap on the end of the handle screw, firmly pushing it into its recessed seat. Test your faucet control by turning it through the hot and cold water ranges. If you need to adjust the pressure balance valve for a different setting, remove the components as you did before and rotate the inner ring clockwise for a hotter temperature, and counterclockwise for a colder temperature.
Source...