Performing a Factory Reset will reset your ZEN's HVAC-system configuration and all of your preferences and advanced settings changes. You should only do this when instructed by a Zen support center assistant.
To restore to factory settings, pull your ZEN Thermostat off the wall and press the CONFIG button on the rear 20 times. The unit will beep five times to confirm the reset.
If you do a Factory Reset, make sure that you set your configuration code and preferences back to their correct values before replacing the display on the wall.