Bock Water heaters OT300-A Installation And Operation Instruction Manual page 21

SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Install piping through the wall as shown in Figure 11. Adequate length of pipe must protrude
beyond the exterior wall for attachment of the termination fitting. The recommended distance
between the terminal fitting and the exterior wall is 1 in. (2.5 cm). Directions for cementing joints
(such as the terminal fittings to the straight pipe) can be found on page 25. A single 90 elbow is
supplied with the water heater for the termination fitting on the air intake. If other fittings are
required they must be purchased separately. Install a screen inside the air intake termination fitting
to prevent items from entering the system. The screen type must be appropriate for an air intake
vent and have a low resistance to airflow. A screen that significantly restricts airflow will reduce
the performance of the water heater and could cause nuisance control lockouts. Complete the
installation of the remainder of the vent and air intake system and attach to the water heater as
shown in Figure 12. Horizontal sections of the exhaust vent shall slope upward away from the
water heater a minimum of 1/8" per foot (10 mm per meter). This will allow the condensate in the
vent to run back to the condensate drain on the water heater. Horizontal sections of air intake
piping shall slope downward away from the water heater a minimum of 1/8" per foot.
Annular spaces around vent pipe wall penetrations shall be permanently sealed using
approved materials to prevent entry of combustion products into the building.
!
CAUTION
Inside of
Building
Vent Pipe
From
Water
Heater
Wall Section View
Figure 11: Horizontal Venting, 1-pipe termination
Figure 12: Horizontal Power Vent Arrangement
Outside of
Building
Vent Terminal
Wall
12" (30 cm)
or greater
Ground Level
Page 21