American Water Heater DIRECT VENT GAS WATER HEATER Installation And Operating Instruction Manual page 23

Installation (Vent-Air Intake System Installation) continued-
12. Mark the mounting screw hole locations for the backing plate. Rotate
the backing plate in order to gain access to the markings. With a 3/16
inch diameter drill bit (not supplied), drill holes for the supplied wall
anchors. Install the wall anchors and secure the backing plate to the
wall with four (4) #10 x 1 inch screws (supplied) (See Figure 15). Note:
Certain construction of walls may require the use of a different type of
anchoring means than supplied.
Figure 15
IMPORTANT
When the installation is complete, visually inspect the air intake
system to insure that all joints are completely sealed.
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