How Do I Change My Differential Setting on My Honeywell CT3600 Thermostat?

Open the thermostat cover to expose the keypad.

Press and hold down the up key, down key and "i" key at the same time until the setup screen appears on the digital display. These keys are on the upper right of the keypad.

Make sure the number on the left is 4. If it is not, press the "Time" forward button until it reads 4.

Press the up key to change the number on the right. Your options will be 1, 3, 6 or 9. These numbers represent cycles per hour.

Press the Run Program key to exit setup.