If the buttons on your iT500 are not working but the thermostat still lights up and shows the current temperature when you press the ‘Display On’ button, then your thermostat has the screen lock feature enabled.

To disable this function and return your thermostat to normal operation please see the details below.

Keys / Buttons needed :        Tick/Confirm         Return / Backup    

Description : The Screen Lock Function disables the use of the thermostat, making the screen unresponsive. A Padlock Icon will display in the upper right corner of the screen.

Enabling and Disabling :

Press and Hold both the Tick  and Return Keys    together until the icon Appears or Disappears.