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Unlocking the Honeywell T4 Pro Thermostat


Have you ever accidentally locked your Honeywell T4 Pro Thermostat? Well, you’ve come to the right place! To help, we’ve put together a step-by-step video explaining the process of how you can unlock your Honeywell T4 Pro Thermostat!






1) From the locked home screen, press the center button.
2) Enter the passcode. The default passcode when the Honeywell T4 Pro is partially or fully locked is 1234. Press the Plus or Minus buttons to change the first digit of the passcode, then press the Select button. Repeat these steps until 1234 is displayed on the screen.
3) Press the Select button. The thermostat will now be unlocked. If the incorrect passcode is entered, lines will flash on the screen. Press the Back button, then follow the previous steps to enter the correct passcode.



For complete instructions and a demonstration, watch this video:

Browse our selection of thermostats, including the Honeywell T-Series at

Posted in All Posts, How Tos + Tricks, Products |

6 Responses to Unlocking the Honeywell T4 Pro Thermostat

  1. kyle says:

    How do you change the password?

  2. After i enter 1233 and hit select, it does not say lock, but still won’t go over the previous set time

    • Gregory says:

      Hi Adam,

      We’d recommend that you confirm that your thermostat is the same model as the one in the video. Other models may have different passcodes. If you are trying to override the programmed setpoint on a thermostat the is not locked, you should be able to use the plus and minus buttons to adjust the temperature.

  3. Kevin says:

    Why would you make a passcode as simple as 1234 and not make an option to change it.

    • Gregory says:

      I’m sorry that you find it frustrating to not have the ability to change the passcode. This is something that has been brought to Honeywell’s attention numerous times, so hopefully they will listen to valued and concerned customers like you and implement your feedback. If you have any questions at all about your thermostat, please don’t hesitate to reach out to us. Thanks!

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