I have a Carrier TC-NHP1 Thermostat. I locked the keypad using code 21 But now I find that I can accomplish the Same thing (Limiting the minimum cool temp.) by using code 26 and minimize the cool temp and still allow me to turn the Thermostat off if I want to. However when I go to code 26 the lower temp indicated is 54 and the highest 86. I use the up and down buttons to change the temp but I can only get 54 0r 86.I want to fix the minimum cool temp to 75. Help