Locate the back of the control unit and note the four screw holes used for securing the control unit to the wall (Figure 6).
FIGURE 6 The control unit (rear view).
As noted in Figure 6, the horizontal distance between the center of these holes measures 8 3/8 inches, and the vertical distance measures 14 7/16 inches. Make note of these measurements since you may need them to locate and drill mounting holes in the wall.
In order to reach the mounting holes from the front of the control unit, you have to remove the front and top covers. Remove the front cover by pressing down on the two top corner tabs and pulling the top away from the control unit, as shown in Figure 7.