Your Zen thermostat controls your heating unit after entering the configuration code into the physical thermostat. If you find that your Zen is not heating when the set point is above the current temperature, you may need to update the configuration code.
During install, the Zen install web-app will display your configuration code. If you did not write the configuration code down, you can find it by following along the install steps on this guide here: zenthermostat.com/install/install
To view your current configuration code, tap the display to wake, then remove the thermostat from the wall and press the "config" button on the rear of the device. Tap "Conf" to see your current setting.
Use the up and down arrows to select the configuration code shown in the installation guide. The code is NOT case-sensitive. Once you have the desired setting, touch the middle of the display to select it (the code will flash to confirm selection), then place the thermostat back on the wall.