How to Lock and Unlock Honeywell ProSeries Thermostats – A Comprehensive Guide

Lock and Unlock Honeywell Pro Series Thermostats - Guide

Want to lock or unlock a Honeywell Pro Thermostat that you own? How to lock and unlock a Honeywell Pro Series Thermostat is explained here.

Regarding heating or cooling your home, thermostats are vital devices in every home. Honeywell is a well-known brand of thermostats. Honeywell makes many different thermostats that you can buy for your house. The programmable and non-programmable options are available. Alternatively, you could choose the Pro or Non-Pro series. You can regulate and manage the temperatures in your home using either option.

When installing thermostats in your home, it is necessary to make sure that the settings and schedules that have been established are not disrupted. Someone will always want to keep changing temperatures, or perhaps a child who wants to play with temperatures all the time. Locking the thermostat is a better option in this case. In this guide, we will show you how to lock and unlock your thermostats easily. 

Understanding the Lock and Unlock Feature

The lock and unlock feature on Honeywell ProSeries thermostats allows users to prevent unauthorized changes to the temperature settings. This feature can be particularly useful in commercial or public spaces where multiple people have access to the thermostat and may inadvertently or deliberately change the temperature.

When the thermostat is locked, users will not be able to change the temperature settings until the thermostat is unlocked. This provides peace of mind for those who want to maintain a consistent temperature in their environment, without having to worry about changes made by others.

How to Lock Honeywell Pro Series Thermostats

Whether you want to lock your settings to the thermostats or unlock them to change the settings, you can easily complete both tasks without much difficulty.

Lock Honeywell T4 Pro Series Thermostats

The Honeywell Pro series thermostats are simple to lock. You can use the Honeywell T4 Pro Series Thermostats by following these steps.

Lock Honeywell T4 Pro Series Thermostats

  1. First, on your thermostat, press the Menu button.
  2. To navigate through the menus, press the Plus or Minus buttons on the thermostat.
  3. Select the Lock option on your screen by pressing the Select button on your thermostat.

Lock Honeywell T6 Pro Series Thermostat

  • If you have a T6 Pro series thermostat, you can lock it easily, but in a different way. Here’s how it’s done:
  • Navigate through the menu by tapping the Menu option.
  • Choose one of the Screen Lock options.
  • You can choose between Full Lock and Partial Lock by tapping on select. Select your preferred option.
  • When you choose either option, the PIN will be displayed. Take note of this PIN because it will be required to unlock the thermostat.

How to Unlock Honeywell Pro Series Thermostats

When you want to change the settings on the thermostat, you must first unlock it. So, here’s how to unlock Honeywell Pro series thermostats.

Unlock Honeywell T4 Pro Series Thermostats

Have you locked your Honeywell T4 Pro series thermostat and need to unlock it? Here’s how to gain access to the same thermostats. Take the following steps.

  • On your thermostat, press the Center button and enter your password.
  • 1 2 3 4 is the default password.
  • You can choose the digits for your password by pressing the + or buttons on your thermostat.
  • Rep the process three times more to successfully enter the password.
  • The thermostat’s keypad has been unlocked once the password has been entered. The T4 Pro Series thermostats’ settings and adjustments can now be changed.

Unlock Honeywell T6 Pro Series Thermostat

If you remember the PIN that was displayed when the T6 Pro series thermostat was locked, you can use it to unlock the same thermostat.

Unlock Honeywell T6 Pro Series Thermostat

  • On the T6 Pro’s screen, tap the lock icon to unlock.
  • Now enter the Pin code.
  • The lock on your T6 Pro Series thermostat has been unlocked.

How to Unlock Honeywell Pro Series Thermostat if you forgot its PIN

You can still unlock your T6 Pro Series if you have forgotten the PIN. Here are the steps you must take care to unlock the thermostat.

  1. Remove the T6 Pro series thermostat from the wall first.
  2. Remove the thermostat’s back plate.
  3. There should be some text at the back. Ans, there are four digits in the upper right corner.
  4. Take note of the digits printed and multiply them by 1234.
  5. The PIN for your T6 pro series thermostat will be the sum of 1234 and the printed digits.
  6. After you’ve written it down, reconnect the thermostat to the wall and tap the lock icon.
  7. Now, enter the PIN derived from the sum of the two numbers.
  8. The T6 Pro Series thermostat is now unlocked.


This is how to lock and unlock the Honeywell T4 Pro and T6 Pro series thermostats. Locking these devices is always a good idea because it helps to regulate the temperatures in your home without them constantly changing.

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