Press the up and down arrows simultaneously for 3 seconds and release. Press the flame/snowflake button to scroll through the settings to dIFF. It is adjustable from .5-3 degrees in .5 degree increments. Press the flame/snowflake button and you will see dIF2 for the second stage differential. It is adjustable from 1-6 degrees in .5 degree increments. Press the flame/snowflake button and you will see dLy2 for the second stage delay. It is adjustable from 5-40 minutes in 5 minute increments. Press the start/stop schedule button to exit the setup.