To adjust the temperature on the Richmond RMTEX-04 Electric Heater, follow these steps: Power On: Ensure the heater is powered on. Use the Keypad: The heater has a digital display and external controls. Use the keypad to adjust the temperature. Set Desired Temperature: Press the right arrow on the keypad until your desired temperature is displayed. The digital display will show the outlet temperature, allowing you to set it in increments of 1°F.