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The significance of a thermostat lock can't be understated, as it prevents kids or guests from tampering with its settings.

Most Honeywell Thermostats offer a couple of lockout modes. You can lock it entirely or only allow changing the temperature.

In this article, I’ll show you how to set these up and unlock them, even without the PIN code!

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Honeywell Thermostat Lock Modes

For your Honeywell Pro Series thermostats, you can lock your keypad in either Full or Partial mode.

  • A “Full” lock prevents any access to the thermostat settings
  • With a “Partial” lock you can change the temperature. Both modes can be unlocked using a PIN, code, or password.
  • I recommend setting your lock to “Partial” if you override the schedule often.
  • Use the “Full” lock if you want to let the thermostat run on the programmed schedule. 
  • However, don’t forget your code. Write it down on your phone or keep it written down in a safe place.
  • Certain models will allow you to bypass the pin but it’s always a good idea to keep the original PIN safe.

Bypass Lockout Modes Via the App

If you or anybody can access the thermostat via the Total Connect Comfort or Honeywell Home apps, you can bypass these lockout modes. As such, these are only considered screen lockouts and won’t block mobile apps.

If you haven't already, I highly recommend pairing your Honeywell thermostat with compatible mobile apps for increased functionality.

How to Unlock a Honeywell Smart Thermostat

Unlocking your Honeywell thermostat may seem complicated, but in this guide, I'll cover most of the common models and their procedures. 

T10 Pro and T9 Models

Smart thermostats with a color touchscreen

T10 Pro

For T9 and T10 Pro models, simply inputting the saved pin code will unlock the screen.

If you’ve forgotten the code, there are several things you can try:

  1. First, see if you can locate a four-digit pin on the back of the thermostat – To do this, you might have to pull out the thermostat from the mounting plate and check the back of the device.
  2. Then plug the thermostat back in and try this four-digit code. 
  3. If it doesn’t work, try adding “1234” to the pin and typing in the last four digits of the sum.
  4. If this doesn’t work, try to access the menu and check for a date code under the “Thermostat Information” menu.
  5. Type in this code or add “1234” and try again with the sum. 

One of these alternatives will most likely help you overcome a forgotten pin. Nevertheless, make sure to keep the original pin written down or use the mobile app to control the thermostat.

T6 Pro Smart, T6 Pro Z-Wave and T5+ Models

Smart thermostats with touchscreen

Honeywell T5 and T6 Pros 1

With the T6 Pro Smart/T6 Z-Wave and T5+ models, simply tap the lock icon on the main screen and follow the prompts to input your PIN correctly.

T6 Pro Smart Unlock 1
Unlocking the screen lock on a Honeywell T6 Pro Smart style thermostat

If you’ve forgotten the code or it’s asking for the code during reset or initial setup, try “1234.”

In the case of the T6 Pro Series, the code can be recovered by removing the thermostat faceplate and locating the four-digit code at the top right corner of the base, followed by adding “1234” to the code.

T6 Pro and T4 Pro Models

Smart thermostat with LCD display

T4 Pro 1

To unlock your T6 Pro and T4 Pro models:

  1. First, press the center button to wake up the screen
  2. Then type in your PIN (usually it's “1234”). Use the + and – buttons to change the numbers and the “select” button to switch to the next digit.
  3. After you press select on the fourth digit, the screen should unlock.
  4. If the code is incorrect, the screen will flash, along with the lines “–“
  5. In this case, press “back” to switch between the digits and change them as necessary.

T6/T4 Pro Series – Can't Remember PIN Code?

The password, code, or PIN on your T6 Pro Series are only four digits. Despite this, it’s possible to forget them.

You might not be using the thermostat that often, especially if your scheduling is sufficient enough. Or perhaps someone else configured the lock set on it.

For the T4 Pro model, the code is simply 1234.

But for the T6 Pro Series, follow these steps to recover it:

  1. Remove the thermostat faceplate and look for a four-digit code on the top right of the base.
  2. Add 1234 to this four-digit code.
  3. The sum will be your thermostat’s password or PIN.
  4. Follow the steps above to unlock your thermostat using the PIN you recovered.

9000/8000 Series

VisionPRO, RedLINK Models, and similar thermostats

90008000 series all

For Honeywell 9000/8000 series thermostats, including the VisionPro and RedLINK models, you can unlock the screen using a pre-set PIN code. Here's how:

Unlocking VisionPRO TH8321WF or VisionPRO Series with RedLINK Models

  1. Tap on MENU
  2. Use the up and down arrows to locate “Security Settings,”
  3. Then, enter the password to unlock the device.

Unlocking the VisionPRO TH8320WF, RTH8580WF, and Similar Models

However, if you've forgotten the code, certain models such as the TH8320WF may allow you to bypass the screen lock using the installer settings menu.

  1. Hold down “System” and “Auto” with two fingers on your display. 
  2. Then, press and hold the blank lower center button, until the display changes. On some models, you might have to hold the 2nd and 4th blank buttons instead.
  3. In this new menu, change the left value to 0670 using the up/down buttons in the middle of the display.
  4. Then, change the right value to 0 using the up/down buttons on the right.
  5. Press “DONE” on the lower right to confirm.

This will help unlock or bypass a screen-locked 8000 series thermostat.

How to Screen Lock a Honeywell Thermostat

As mentioned, the screen lock feature can be helpful in certain instances. So, let me walk you through how to do this for each supported model.

T10 Pro and T9 Models

Smart thermostats with a color touchscreen

T10 Pro
  1. Start by touching the display to wake it up.
  2. Then, touch the MENU icon and scroll down to Security.
  3. Select either “Change lock mode” or “Create Password.”
  4. Lock modes include Unlocked, Partially locked, and Fully locked.

T10 Change lock mode 1
Changing the screen lockout mode on a Honeywell T10 smart thermostat

T6 Pro Smart, T6 Pro Z-Wave and T5+ Models

Smart thermostats with touchscreen

Honeywell T5 and T6 Pros 1
  1. Touch “Menu” on the thermostat home screen.
  2. Then, tap on the left or right arrows until you see SCREEN LOCK, then tap on “Select.”
  3. Use the left or right arrows to select the screen lock setting you want. 
  4. Then, touch on “Select” to confirm.
  5. A PIN will appear on the screen. Write it down and keep it safe.
  6. Touch Select again.
  7. Then, confirm your screen lock setting by tapping on “Yes.”
T6 Pro Smart Lock Instructions
Setting up the screen lock on a Honeywell T6 Pro Smart style thermostat

T6 Pro and T4 Pro Models

Smart thermostat with LCD display

T4 Pro 1
  1. Press Menu on the thermostat.
  2. Press the “+” or “-” button to go to choose “LOCK.” 
  3. Press Select.
  4. After that, use the + and – buttons to switch between OFF, PART, or ON. Here, “PART” means partial lock, and “ON” means full lock
  5. Make your decision and then press “Select.”

9000/8000 Series

VisionPRO, RedLINK Models, and similar thermostats

90008000 series all

Depending on certain models, you can seamlessly lock the screen using the security settings menu. For the rest, you might have to head over to the installer settings and set it up.

Screen Locking VisionPRO TH8321WF or VisionPRO Series with RedLINK Models

First, let me show you the first method. This is suitable for models like the VisionPRO TH8321WF or VisionPRO Series with RedLINK models (with the -R suffix):

  1. Touch “MENU”
  2. Scroll down to “Security Settings”. If you haven't created a password, you can tap on “Create Password” instead and finish setting it up
  3. After you've created a password, tap on “Change Lock Mode”
  4. Select the lockout mode
  5. Then, tap on “Done” to save changes and return to the HOME screen.
8000 series security instructions
Locking the screen in Honeywell 8000/9000 series thermostats

Screen Locking the VisionPRO TH8320WF, RTH8580WF, and Similar Models

For the second set of models, via installer settings:

  1. Press “System” on the display.
  2. After that, press and hold the blank center button, until the display changes. On some models, hold the 2nd and 4th blank buttons.
  3. A new screen will pop up. Using the up/down buttons in the display, change the left values to 0670 using up/down buttons in the middle of the display.
  4. Then, change the right value depending on the lock mode. Here, “1” stands for Partial lock and “2” for Full lock. Meanwhile, “0” removes any lockout mode from the thermostat.
  5. After making the change, press “DONE” on the lower right to confirm.

Why are Passwords and PIN Codes Used in Honeywell Thermostats?

Passwords and PIN codes serve an important role in Honeywell thermostats as a means of ensuring privacy and protecting temperature settings.

Primarily, they are used to unlock the screen, preventing unauthorized users from tampering with the system.

This can be especially useful for households with children or guests who may inadvertently change the temperature settings.

Additionally, passwords are utilized to access the installer settings in older thermostat models, providing an extra layer of security for important system configurations.

Common PIN Codes

Unlocking your Honeywell smart thermostat doesn't have to be a challenge, especially when you can follow these easy steps to find the common PIN codes or derive the right one.

  1. Begin by trying the simple default PIN “1234.”
  2. Look for a four-digit number printed on the back of the thermostat and test that as your PIN.
  3. In some cases, adding “1234” to the four-digit number from the back of your thermostat can create your PIN—enter the new four digits.
  4. Access the “Thermostat Information,” “Device Info,” or “Dealer Information” menu on the homescreen, and use the displayed date code as your PIN.
  5. Another option is to add “1234” to the date code, and then enter the final four digits as your PIN.

If you still can't unlock your thermostat, you may need to use a previously created customized PIN or consult a professional for support.

Conclusion

For Honeywell thermostats, the available lockout modes are always the same: off, partial, or full. However, as long as you don’t forget your codes, or you can manage the thermostat via the mobile app, you should be fine. 

Certain models have several bypass methods in place so don't forget to check the guide above if you need to get access. You can also download the specific manual here if my instructions above don't cover it.

References

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