Thermostat screen is locked

How can you tell the screen is locked?

Press a button or touch the screen and watch what happens. A locked thermostat nearly always tells you, either with a word or a padlock. A thermostat that is frozen, blank or dim shows nothing of the kind, and that points somewhere else.

Here is what each manufacturer says its screen shows:

What a locked thermostat shows, by model

Thermostat	What you see	What it means
Honeywell Home T4 Pro and T6 Pro	"unlock" on the display; temperature settings do not change	The owner has set a lockout setting
Honeywell Home VisionPRO TH8000	"SCREEN LOCKED" for several seconds after you press a locked key	Partial lock. On a full lock no keys work at all
Honeywell Home VisionPRO TH8000	"OK TO CLEAN SCREEN" with a countdown	Screen cleaning lock; it ends after 30 seconds
Honeywell Home T9	A countdown after "Clean Screen"	Screen cleaning lock; it ends after 30 seconds
Google Nest Thermostat E and Learning Thermostat	A lock icon at the bottom of the screen	PIN lock. The ring still works inside the allowed range
Sensi Smart	A padlock next to the room temperature	Keypad lockout is on
Sensi Lite	A padlock when you press the menu button	Keypad lockout is on
Sensi Touch and Touch 2	A padlock on the touchscreen	Keypad lockout is on
Sensi (any model)	"Limit" when you push the setpoint too far	Temperature Limits are set in the app
ecobee	Not stated	A security code blocks some settings

Who locked it, and why?

Usually whoever controls the system: a landlord, a property manager, an installer, or the person who lived there before you. Every lock in the table above is a setting someone chose. None of the manufacturers we checked describes a thermostat locking itself as a fault.

That matters, because the fix depends on who holds the code or the app account. Google Nest and ecobee locks use a code chosen by the person who set them. A Sensi lock lives in the Sensi app account. On Honeywell Home T4 Pro and T6 Pro models, the manuals publish the unlock code itself. The full steps for each brand are on our keypad lock settings page.

On a Google Nest, the lock only applies at the wall. Google says anyone with access to the home in the app can still change settings or unlock it there, without the PIN, as long as the thermostat is online. So a household member with the app may be able to free it in seconds.

ecobee notes a common case: moving into a home where the thermostat is still protected by the previous resident's security code. It suggests asking that person or the landlord first, and calling ecobee support with the serial number if you cannot reach them.

Is it locked, or just limited?

Look at what happens when you press the up or down button. If the number moves but stops at a certain point, you are hitting a limit, not a full lock.

• Honeywell Home T6 Pro: the user guide says that if you cannot set heat anywhere from 40°F to 90°F, or cooling from 50°F to 99°F, range stops may be restricting you, and to check with the installer.
• Sensi: Temperature Limits make the thermostat and the app show "Limit". They can only be changed in the Sensi app.
• Google Nest: a locked Nest lets anyone turn the ring within the range the owner chose, but not beyond it.

A partial lock behaves similarly: Honeywell's "PART" setting and the T9's "Partially locked" leave the temperature adjustable and block everything else.

What if there is no lock message at all?

Then a lock is less likely, and a few other things can make buttons seem dead.

On a Honeywell Home T4 Pro or T6 Pro, the troubleshooting table says to check that you are in the right mode, such as heat, cool or auto, when temperature settings will not change. A thermostat in Off mode ignores setpoint changes for heating and cooling. Sensi's Lite installation guide, for buttons that do not work at all, says first to make sure keypad lockout is not turned on.

If the display itself is dark or fading, see thermostat screen is blank. If the temperature changes but then changes back on its own, the cause is the schedule, not a lock; see thermostat schedule periods. A Nest also follows its Eco temperatures while locked.

Does the screen show "unlock", "SCREEN LOCKED", a padlock or a lock icon?

• Yes

  Do you know the code, or have the app account the thermostat is registered to?

  • Yes

    Unlock it with the steps on the keypad lock settings page.

  • No

    Ask the landlord, installer or previous resident. ecobee support can release a security code if you send the serial number.

• No

  Does the setpoint move but stop at a certain number, or show "Limit"?

  • Yes

    That is a temperature limit or range stop. The owner or installer can change it.

  • No

    Check the mode is not Off. If the screen is blank, dim or flickering, see the signs at the bottom of this page.