Danfoss DEVIreg Basic Installation Manual page 22

DEVIreg™ Basic
Factory reset
To perform a factory reset the thermostat needs to be powered and
correctly mounted, on the bottom of the device (circled below) is a pin
hole, by pressing a needle into this pinhole a button will be activated,
after 20-30 seconds of activation of this button the thermostat will
perform a factory reset . All indicators will flash briefly to inform about
successful factory reset .
The thermostat will briefly be rebooting please allow for up to 5 seconds
for the thermostat to be back to a responsive state .
Performing an factory reset will reset errors and warnings .
Alternative method, the front cover on the thermostat can be removed
using the slot on the bottom of the thermostat and the button can be
activated with a finger or similar .
The factory reset can only be performed whilst the thermostat is powered .
Installation Guide 23