Shower faucets are adjustable using a dial that's inside the faucet handle. This feature adjusts the ratio of hot to cold water coming through the faucet, allowing you to set a maximum or minimum faucet temperature to prevent scalding or to increase the temperature when necessary. For instance, if your groundwater is cold in winter, turning the adjustment to increase your water temperature during that time makes for warmer water. Just be sure to turn it back if the water becomes too hot in the summer. Adjusting the water temperature for your shower faucet takes only about 10 minutes. Do it any time water is too hot or cold.
Turn the water off to prevent accidental leaks and problems as you work: Access and turn off the shower water pipe valves through the access panel in the shower wall, or shut off the home's main water valves.
Take off the handle to the shower faucet by locating the small screw in the handle near the base. Loosen this with an Allen wrench and slide off the handle.
Remove the trim sleeve (if your faucet has one) and any remaining parts, like the handle adaptor kit, by unscrewing them from the faucet head. You will see a round dial that looks like a needle gauge on top of the faucet fixture.
Turn the dial knob (a triangular button) to the left. This action decreases the rotation of the faucet, so a smaller amount of hot water is allowed to mix in with the cold water, creating cooler water. If you want hotter water, turn it the other way. Follow the indications on the part to ensure you're increasing or decreasing the hot water as necessary.
Replace the trim sleeve and handle and turn the water on. Test the faucet and readjust by following the same procedure as needed until the water is the perfect temperature.