Combustion Air Requirements; Proper Location For Installing Your Heater - Bosch 830 ES Manual

1. The referenced "special venting system" instructions shall be included
with the appliance or equipment installation instructions; and
2. The "special venting systems" shall be product approved by the
Board, and the instructions for that system shall include a parts list and
detailed installation instructions.
(e) A copy of all installation instructions for all products approved side
wall horizontally vented gas fueled equipment, all venting instructions,
all parts lists for venting instructions, and/or all venting design
instructions shall remain with the appliance or equipment at the
completion of the installation.
4.4

Combustion air requirements

CAUTION:
▶ In areas where outside temperatures routinely come
close to freezing, sealed combustion operation is
required. Use a concentric termination or separate
terminations for combustion and vent, which must be
installed on the same wall or roof surface, however
never facing the direction of prevailing winds. Failure
to do so may result in heat exchanger freezing up and
bursting. This failure is not covered under the
manufacturer's warranty.
CAUTION:
▶ When installed in an environment where corrosive
chemicals or dirty air (e.g. hair salons, car washes)
are present the twin pipe system is required.
Twin pipe and Concentric pipe
The water heater is designed as a sealed combustion appliance. It is
recommended that the combustion air be provided by a dedicated 3" or
4" pipe from the outside (twin pipe) or by connecting to the Concentric
vent kit (see Fig.8, 9 & 10). The combustion air pipe may be PVC or any
other rigid sealed 3" or 4" pipe. The combustion air piping must pitch
down 1/4 inch per foot towards termination to prevent rain water from
entering the appliance. In twin pipe penetrations, the combustion air
inlet, whether terminating vertically or horizontally, must be located in
such a manner as to provide a minimum 3 foot clearance from the
exhaust vent termination. See Fig.11 and 12 Letter I, page 14.
For the maximum length of the combustion air pipe, see Table 9.
CAUTION:
▶ Terminations must prevent rain and debris from
entering the combustion air and exhaust vent piping.
Single pipe
WARNING:
▶ Single pipe venting is forbidden in manufactured
(mobile) home installations.
Note: This appliance requires 9950 cubic feet of available
combustion air, or a minimum of 1243 square feet of space with an
8 foot ceiling to operate. If the large amount of air space, which
equates to about half of most average sized homes, is not available,
the appliance must pull air from the outside (see twin pipe above).
Although it is permissible to draw combustion air from inside the
structure, it is not the manufacturer's recommended installation
method. Always install a 3 inch elbow on the top of the combustion air
inlet adaptor to prevent foreign objects from falling into the unit.
If a single pipe installation is utilized, follow guidelines below for
providing adequate combustion air for the water heater as well as any
830 ES
other appliances that may consume air in the space. Always follow local
codes if they are more stringent.
This Installation Manual specifies the minimum vertical vent pipe and the
amount of combustion air required for this unit. When all requirements
are followed, the unit will operate properly and safely. However, there
may still be a risk of freezing due to negative draft if the other
combustion appliances in the building are not supplied with sufficient
combustion air. A wood stove or furnace can pull its combustion air from
the heater's vent pipe, allowing the cold incoming air to freeze the cold
water in the heat exchanger. Supplying more combustion air for all
combustion appliances is the solution. A HVAC specialist should be
consulted to design solutions for providing more combustion air.
Observe the following guidelines:
Installations in structures that have been tightly constructed (air
infiltration rate of 0.40 ACH or less) must be provided with combustion
air per the National Fuel Gas Code. Consult a HVAC specialist if your air
infiltration rate is questionable.
The space must have two permanent openings, one commencing within
12 inches of the top and one commencing within 12 inches of the
bottom of the enclosure.
• Appliances located in unconfined spaces:
– a) An unconfined space is one whose volume is greater than 50
cubic feet (1.42 cubic meter) per 1000 BTU/hr (292.81 Watts) of
the combined rating of all appliances installed in the space. That
would be 9950 cubic feet (281.8 cubic meters) for the water
heater alone.
– b) In unconfined spaces in buildings of conventional frame,
masonry, or metal construction, infiltration air is normally
adequate to provide air for combustion.
• Appliances located in confined spaces:
The confined space must be provided with two permanent openings,
one commencing within 12 inches (304.8mm) of the top and one
commencing within 12 inches (304.8mm) of the bottom of the
enclosure. Each opening must have a minimum free area of one
square inch per:
– 1000 BTU/hr (292.81 Watts) if all air is taken from inside the
building
– 2000 BTU/hr (585.62 Watts) if all air is taken from the outside by
horizontal ducts
– 4000 BTU/hr (1171.24 Watts)if all air is taken from the outside by
direct openings or vertical ducts
Or the confined space must be provided with one permanent opening or
duct that is within 12 inches (304.8mm) of the ceiling of the enclosure.
This opening must have a minimum free area of one square inch per:
– 3000 BTU/hr (878.43 Watts) if all air is taken from the outside by
a direct opening or vertical duct.
Louvers, grills and screens have a blocking effect, when used, increase
the sizes of your openings by 300% for wood louvers (as wood type will
reduce the free air by 75%) and 43% for metal louvers (as metal will
reduce the free air by 30%). Refer to the National Fuel Gas Code for
complete information. In buildings of tight construction all air should be
taken from outside.
4.5

Proper location for installing your heater

Carefully select the location of the water heater. For your safety and for
proper heater operation, you must provide combustion air to the heater
and a proper exhaust vent system.
Follow the guidelines below:
▶ 1. Locate the heater where venting, gas and plumbing connections
are feasible and convenient.
▶ 2. The hot water lines should be kept short and insulated to save
energy. Centrally locating the water heater is recommended to keep
hot water distribution times even throughout the structure.
Installation instructions | 23
6 720 644 936 (2013/01)