How to Lock and Unlock Honeywell ProSeries Thermostats

Written by: Ahmad Aziz
Reviewed by Editorial Team

Installed Honeywell Pro Thermostat in your home and don’t want people to mess around with its settings? Well, there’s a solution: locking your thermostat.

If you have kids in your house, it always advisable to keep your thermostat in lock mode to prevent them from changing temperature.

The Honeywell Pro Series has 2 lock options:

Partial Lock: In ‘Partial Lock’, you will be able to change the temperature, but other settings will remain locked.

Full Lock: In ‘Full’ lock, your Honeywell Thermostat will not allow you to access any setting until it is unlocked.

How to Lock and Unlock Honeywell T4 Pro Thermostat

How to Lock?

To lock T4 Pro Thermostat, press ‘Menu’ button.

Use the ‘+’ and ‘‘ to navigate the menu to get ‘Lock’ option and confirm it by pressing ‘Select’ button.

How to Unlock?

To unlock Honeywell T4 Pro, press the center button.

Now enter the PIN code to unlock it. The default PIN is ‘1234’.

To enter PIN, change the number with ‘+’ and ‘‘ buttons on the top and press select button for selection.

Repeat these steps until your PIN code is displayed on screen and then press ‘Select’ button.

How to Unlock Honeywell T6 Pro Thermostat

Instructions to Lock

To lock Honeywell T6 Pro thermostat, tap on ‘Menu’ and the navigate to “Screen Lock’ option.

Tap ‘Select’ and choose either ‘Full Lock’ or ‘Partial Lock’.

Before you confirm the lock, you will see PIN on the screen. Note that down because you will need it when unlocking your thermostat.

Instructions to Unlock

To unlock, tap on the ‘lock’ icon. Enter the PIN/code and then tap on ‘Select’ to unlock it.

To unlock Honeywell T6 Pro without knowing the PIN, get it off the wall and remove its plate. Look for 4 digit code at the top right corner, and then add ‘1234’ to this code. The resultant 4-digit code will be your PIN.

For example, if the 4 digit code on thermostat is 2022, so after adding 1234 to this code, the resultant number is 3256 which is the PIN (2022 + 1234 = 3256).


Lock feature on Honeywell thermostats can be quite useful to secure your thermostat settings according to your likings especially when you have many people in the house.

If there ever comes a time when you need to lock your Honeywell Pro Thermostat, just access the menu and select the lock option from there.

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