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

Yous can change the temperature differential on a Honeywell CT3600 thermostat by adjusting the cycle rate. The cycle rate determines how often heating is turned on and off over a specific period of time. If you want your heating unit to turn on less frequently and run longer, lower the cycle rate. The default cycle rate on a CT3600 is 6 cycles per hour (cph). The cycle rate does not affect cooling. You cannot change the differential setting by a specific number of degrees on digital Honeywell thermostats.

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.

Tip

  • Honeywell recommends these settings for cycle rate: 1 for a gravity or steam system; 3 for hot water, a high efficiency furnace (90 percent or better), or a single stage heat pump; 6 for a gas or oil forced air furnace; and 9 for an electric furnace.

Warning

  • Certain heating systems may not work properly if the rate cycle is increased to more than the recommended rate.

About the Author

Alan Sembera began writing for local newspapers in Texas and Louisiana. His professional career includes stints as a computer tech, information editor and income tax preparer. Sembera now writes full time about business and technology. He holds a Bachelor of Arts in journalism from Texas A&M University.