Braeburn 6400 User Manual - Manual (Page 30)

User Manual 30
If you entered a valid code the thermostat will be locked or unlocked
(depending on its previous state). When locked, the word LOCKED
appears in the display (Figure 3). If an invalid code is entered the
word NO will briefly appear, indicating that an incorrect code was
entered (Figure 4).
Figure 3
Figure 4