How To Unlock A Honeywell Thermostat: Easy To Follow Guide

lock mode on honeywell thermostat

As smart home devices grow in popularity, programmable thermostats like those made by Honeywell enable homeowners’ greater control over managing their HVAC systems efficiently.

However, Honeywell thermostats also come with lock modes to restrict changes, which can cause frustration if you get locked out of your device!

This guide will explore the lock options in Honeywell thermostats, when you may want to use them, and provide easy and step-by-step guide for unlocking the most popular Honeywell models.

Read on to learn how to take back control of your temperature settings.

Related: Honeywell Thermostat Not Working

What are the Different Screen Lock Modes in Honeywell Thermostats?

Honeywell thermostats offer users the ability to lock the devices to control access to the settings.

There are three different lock settings options available:

Full Lock (Shown as “On” on Display)

This locks down the entire thermostat keypad, preventing any changes to settings. When in full lock mode, users cannot adjust the temperature or any program settings. The screen will typically indicate “Locked” when you try to make changes while in full lock.

Partial Lock (Shown as “Part” on Display)

Partial lock allows users to adjust the set temperature but blocks access to the menu and programming functions. So, if you want guests or kids to be able to tweak the temperature for comfort, but not mess with your schedule, partial lock is ideal. The screen will show the lock icon while in partial lock but will allow changing the setpoint temperature.

Unlocked (Shown as “Off” on Display)

This disables any lock on the thermostat allowing full access to all controls and programming functions via the thermostat itself. Users can freely adjust any settings when the thermostat is unlocked.

There will be no lock shown on the screen while it is in the unlocked mode.

To toggle between lock modes, users typically have to enter a 4-digit PIN (Personal Identification Number).

The default is often set to “1234” initially. Once unlocked, users can select between full lock, partial lock, or unlock modes based on their needs. As a safety precaution, be sure not to lose or forget your thermostat lock PIN code.

When Can You Lock Your Honeywell Thermostat?

Locking your Honeywell thermostat can be useful in certain situations when you want to control or restrict access to changing the temperature or programming settings.

Here are three of the most common scenarios when locking a Honeywell thermostat would be applicable:

1. Rental Properties

If you own a rental property such as a vacation home, Airbnb, or short-term lease, locking the Honeywell thermostat allows you to set a comfortable temperature that your guests can enjoy, while preventing them from drastically altering the settings which could waste energy.

You can set the thermostat to partial lock mode so tenants can make small temperature tweaks if overly hot or cold. And you don’t risk guests completely changing your programmed schedule that optimizes heating and cooling for efficiency.

Just be reasonable with the temperature range so as not to receive complaints from guests. But the lock feature grants peace of mind.

2. Homes with Children

Kids playing with or attempting to adjust your thermostat could lead to frustration over comfort or even safety issues with extreme cold or heat if electronics are misused. The lock modes let parents manage the temperature control, so children won’t accidentally change heat or cooling outside a reasonable range you pre-approve.

Again, partial lock here makes sense if you want your kids to have some control over temporarily adjusting the temperature a few degrees when needed.

3. Work Offices

Commercial buildings could benefit from locking thermostats so employees cannot alter programmed settings that managers carefully calibrated for optimal energy efficiency and flow with workplace occupancy hours.

Keeping the Honeywell locked can also prevent office arguments over conflicting temperature preferences.

Managers can make sure temperatures are compliant with safety, building codes, activities, weather patterns, and many other factors for the health and satisfaction of all personnel.

So, in summary, locking your Honeywell thermostat provides added control, restrictions, and security from changes by tenants, children, and employees. It grants oversight for efficiency, billing, safety, preferences and prevents potential damage or disruption from access by others.

How to Unlock Honeywell Thermostat

how to unlock a honeywell thermostat

So far, you now know the different lock modes available on Honeywell thermostats and when it’s appropriate to put a lock on your thermostat.

Now, one thing is locking the thermostat, and another is unlocking.

If you locked your Honeywell thermostat possibly because you had guests coming over and now, they are gone you want to gain full access to your thermostat but don’t know how to unlock it. Lucky for you, this section is going to address just that.

Without further ado, let’s dive into the steps involved in unlocking Honeywell thermostats whether in full lock mode or partial lock mode.

General Honeywell Unlocking Guide

Different Honeywell models may have slightly different steps to follow to unlock them. If you don’t know the exact model or you are not sure of the model you are using, you can try these general steps to unlock or troubleshoot your thermostat.

Step 1: Press and hold the main button

Your Honeywell thermostat should have a main button. To unlock your device, press and hold the main button.

Step 2: Input your lock key

After pressing and holding the main button, hit “Unlock.” Now you’ll be required to input your unlock key. Type in the key “1234.” You can use the +/- (plus/minus) keys on the display to input the keys – the + increases the number while the – button reduces it. Toggle with both the plus and minus buttons until you have arrived at your desired key.

Note: “1234” is the default unlock key. However, if you have changed the default key in the past, then you’ll have to input the new key instead of the default key.

But what if I have forgotten my new key? If you have, it’s not the end of the world. The good news is you can override it.

To override your lock, simply remove your thermostat’s faceplate and look at the top right corner. There you’ll find four digits.

Once you find it, unlocking or overriding it becomes easy, all you have to do now is add “1234” to the four-digit code you found and that should unlock the device.

Step 3: Tap on “Select”

Once you are done inputting your unlock key, tap on “Select” to complete the unlocking process. Doing that transfers the information to your thermostat.

Step 4: Repeat

Sadly, you can’t put in all the numbers at once, you’ll have to do it one after the order. What this means is that you’ll have to repeat steps 2 and 3 until you have inputted the default key, your new pin, or the override pin in the proper order.

Step 5: Access the setting

Now once all the unlock keys have been inserted, hit “Select” one more time. Once you do that, the lock of your Honeywell thermostat will become unlocked.

Step 6: Try again

Is your device still locked? Chances are you might have put in a wrong number or added more numbers than required. In this case, you’ll be redirected to a new screen, on that screen hit “back” to re-enter the password.

As mentioned earlier, some Honeywell models might have slightly different steps. Let’s take a look at the steps involved in unlocking the most popular ones.

How to Unlock Honeywell 8000 Series Thermostat

To unlock a Honeywell 8000 series, follow the instructions below:

Step 1: Enter Known Passcode

If you know the passcode, follow these steps:

  • Enter the passcode when prompted on the screen
  • Tap “Done” after entering full code
  • Press the “Menu” button
  • Use your arrow keys to scroll down to “Security Settings”
  • Select the “Unlock” option

Step 2: Find Unknown Password

If you have forgotten your password/unlock PIN or you don’t know it, there are a couple of ways to find it:

  • First, remove the thermostat faceplate
  • Look for a 4-digit passcode printed on a sticker (it is usually found at the top right corner)

If you have searched for the sticker but can’t seem to find it, you can still recover the unlock key by doing the following:

  • When the passcode screen appears, select “Cancel”
  • Use arrow buttons to locate the “Equipment Status” menu
  • Scroll down to the “Date Code” option
  • The date code number displayed is the passcode

Step 3: Enter Located Passcode

Now that you have access to the the passcode, do the following to complete the unlocking process:

  • Enter the 4-digit number you obtained on the screen
  • Tap “Done” after entering full code

Step 4: Lock/Unlock Thermostat

So, if you happen to need to lock your 8000 series thermostat again, you can do so by:

  • Pressing the “Menu” button
  • Use the arrows to scroll down to “Security Settings”
  • Select the “Change Lock Mode” option
  • And finally, Choose between “Full Lock” or “Partial Lock”

Still using the default passcode? You can change it to your preferred passcode (please use a code you can easily remember when changing it):

  • In the Security Settings menu select “Create Password”
  • Enter a new preferred 4-digit passcode

This new code will now be required anytime you want to unlock your device.

Alternative Unlock Method

  • Hold the “System” and “Auto” buttons
  • Press and hold the blank key till the display changes
  • Change the left digits to 0670 using the up and down keys in the middle of the screen
  • Change the right digit to 0
  • Press “Done” to unlock

In summary, to unlock the 8000 series Honeywell thermostat, you can either enter the known passcode, locate an unknown passcode printed on the device or access the date code, or use an alternative process by holding certain buttons, entering 0670, and changing digits.

How To Unlock Honeywell T6 Series Thermostat

To unlock a Honeywell T6 series, follow the instructions below:

Step 1: Unlock Thermostat

  • Press the center button on the front of the thermostat underneath the word “Unlock”
  • Enter 4-digit passcode (default is 1234)

Step 2: Enter Passcode Digit-by-Digit

  • Use the + or – buttons to select the number
  • Press the “Select” button after choosing digit
  • Repeat steps for all 4 digits

Step 3: Access Unlocked Thermostat

After entering the complete passcode, press the “Select” button once more. Congratulations! Your Honeywell T6 series thermostat is now unlocked

Locking the Honeywell T6 Series Thermostat

If you happen to have to lock it again, you can do so by:

  • Pressing the center button to access the menu
  • Next, press the + button repeatedly until “Lock” appears
  • Then press “Select”
  • Press the + button to select Full or Partial lock
  • Press “Select” again

Voila! Your thermostat is now locked.

How to Unlock Honeywell T6 Pro Series Smart Thermostat

To unlock a Honeywell T6 pro series, follow the instructions below:

  • Tap the padlock icon on the T6 Pro display to bring up the PIN unlock screen.
  • Enter the 4-digit PIN using the +/- keys to select digits and the ‘Select’ button to confirm digits. The default PIN is usually 1234.
  • With the correct PIN entered, the thermostat will unlock, enabling full access to settings.

How To Unlock Honeywell T4 Series Thermostat

To unlock a Honeywell T4 series, follow the instructions below:

Step 1: Locate “Unlock” Button

The unlock button is usually found at the bottom center button on the keypad.

Step 2: Press Unlock Button

Pressing this will allow you to input the 4-digit passcode.

Step 3: Enter 4-Digit Passcode

Now you can input your 4-digit passcode:

  • The default passcode for the T4 series is 1234
  • Use +/- buttons to select each digit
  • Press “Select” after choosing each number
  • Repeat until all 4 numbers entered

Step 4: Access Unlocked Thermostat

If you input the correct passcode, you should now be able to have access to your Honeywell T4 series thermostat without restrictions.

How to Unlock Honeywell T4 Pro Series Programmable Thermostat

To unlock a Honeywell T4 pro series, follow the instructions below:

  • Press the center button labeled “Unlock” on the T4 Pro thermostat.
  • Key in the default password ‘1234’ using the +/- keys to adjust each digit and the ‘Select’ button to confirm each number.
  • Once the correct 4-digit code is entered, the thermostat will unlock, allowing full access to settings.

How To Unlock Honeywell RTH8500D Thermostat

To unlock a Honeywell RTH8500D, follow the instructions below:

Step 1: Tap System Button

The system button is usually located on the left side of the screen.

Step 2: Hold Down 2nd & 4th Buttons

Hold down the 2nd & 4th buttons for at least 5 seconds.

Step 3: Scroll to 0670

Use arrow buttons on the left side to select 0670.

Step 4: Select Lock Options

You can now vary the lock options by doing the following:

  • To unlock fully, use right/middle arrows to set digit to 0
  • To lock partially, set digit to 1
  • To lock fully, set digit to 2

Step 5: Tap “Done”

Complete the unlocking/locking process by selecting “Done.”

How To Unlock A Honeywell FocusPro 5000 And 6000

Honeywell FocusPro thermostats are popular programmable models often found in commercial buildings, apartments, hotels, etc.

The building managers usually lock these thermostats to prevent tenants or guests from adjusting the temperature beyond certain limits.

However, with a few simple steps, these locks can be easily bypassed to allow full control of the thermostat settings.

To unlock a Honeywell FocusPro 5000 and 6000 series, follow the instructions below:

  • Press and hold the ‘Fan’ button and the up arrow button simultaneously until the display changes, indicating it has entered the setup menu.
  • Press the ‘Next’ button repeatedly until the display shows option ’27’ for FocusPro 5000 or option ‘021’ for FocusPro 6000. This allows adjusting the maximum heat temperature limit.
  • Use the up/down arrow buttons to set the maximum heat temp limit to 90°F. This effectively removes any upper limit restrictions.
  • Press ‘Next’ again until the display shows option ’28’ for FocusPro 5000 or option ‘022’ for FocusPro 6000. This is to set the minimum cool temperature limit.
  • Similarly, use the up/down arrows to adjust the minimum cool temp limit to 45°F, removing any lower limit restrictions.
  • Press ‘Done’ once finished to save the new unlocked settings. The thermostat is now fully unlocked.


And there you have it – with the right technique, unlocking any Honeywell thermostat is a straightforward process.

The key things to remember are the default passcodes for your specific model, how to navigate the menu options to disable locking modes, and what to do if you get stuck.

While locking your thermostat provides some useful access control benefits in certain situations, it’s good to know how to bypass those restrictions when needed.

Hopefully these simplified, friendly instructions will allow you to tweak your program schedules and resume full control with ease.

The ability to set customized temperature ranges for comfort, efficiency, and safety is one of the key perks of today’s smart climate control systems after all.

So, unlock that thermostat and start enjoying maximum benefits from your Honeywell unit today!

Related: Honeywell Customer Support

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