1Horizontal Venting; 2Vertical Venting - Bosch 520-HN -L Manual

14 | Installation instructions
WARNING:
▶ Do not combination vent with a power
vented appliance.
4.5.1 Horizontal venting
WARNING:
▶ Horizontally venting to a vertically
constructed vent stack along an outside
wall of a building is not permissible.
WARNING:
▶ Horizontally venting to a sidewall vent
terminator (without powervent) is not
permissible.
An AQ4 powervent, with a proof-of-draft safety interlock
device, is required and is available for sidewall venting. Contact
your dealer. In the Commonwealth of Massachusetts power
vented applications must utilize proof-of-draft safety interlock
device and comply with regulations established for all side wall
horizontally vented gas fueled equipment.
4.5.2 Vertical venting
▶ A 5 inch diameter gas vent constructed of double wall Type
B gas vent is recommended. A 6 inch vent is required in
elevations greater than 2000 feet, see Fig. 10 Under no
circumstances must the vent pipe be reduced in size.
▶ An approved gas vent connector must be attached to the
top of the water heater and rise vertically at least 12"
before entering into an approved gas vent connector
elbow.
▶ The minimum vertical gas vent height allowed is 6 feet;
horizontal vent connectors and elbows are not to be
considered in the total gas vent height.
▶ All gas vent sections must be secured to each other with
sheet metal screws and be properly supported.
Horizontal runs:
Any gas vent section that is greater than 45 degrees from the
vertical is considered horizontal. Horizontal sections must
slope upwards at least ¼ inch for every foot of its horizontal
length and be properly supported. Keep the horizontal section
short and avoid too many elbows. The maximum horizontal run
allowed is half of the total vertical vent height; horizontal vent
connectors and elbows are not to be considered in the total gas
vent height.
6 720 644 942 (2014/11)
Vent termination:
The gas vent constructed of double wall Type B gas vent must
terminate above the roof surface with a listed vent cap at a
height that's in accordance with Fig. 9 and table 5, provided
they are at least 8 feet (2.4 m) from a vertical wall or similar
obstruction. All other gas vents that are not able to terminate
within the minimum specified height allowed must terminate
not less than 2 feet (0.6 m) above the highest point where it
passes through the roof and at least 2 feet (0.6 m) higher than
any vertical wall or similar obstruction within 10 feet (3.1 m).
ESTABLISH A ONE
FOOT RISE BEFORE
ANY ELBOWS
Fig. 9 Flat roof
[1] Listed vent cap
[3] Listed gas vent
[A] Minimum 6 feet (1,8m)
520 HN