Combustion Air Requirements - Bosch 940 ES Installation And Operating Instructions Manual

EXEMPTIONS: The following equipment is exempt from 248
CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled "Equipment Not
Required To Be Vented" in the most current edition of NFPA 54
as adopted by the Board; and
2. Product approved side wall horizontally vented gas fueled
equipment installed in a room or structure separate from the
dwelling, building or structure used in whole or in part for
residential purposes.
(c) MANUFACTURERS REQUIREMENTS - GAS EQUIPMENT
VENTING SYSTEM REQUIRED. When the manufacturer of
Product Approved side wall horizontally mounted gas
equipment provides a venting system design or venting system
components with the equipment, the instructions provided by
the manufacturer for the installation of the equipment and the
venting shall include:
1. Detailed instructions for the installation of the venting
system or the venting system components: and
2. A complete parts list for the venting system design or venting
system.(d)MANUFACTURER REQUIREMENTS - GAS
EQUIPMENT VENTING SYSTEM NOT PROVIDED. When the
manufacturer of a product approved side wall horizontally
vented gas fueled equipment does not provide the parts for the
venting of flue gases, but identifies "special venting systems,"
the following requirements shall be satisfied by the
manufacturer:
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.
940 ES – 6 720 644 930 (2019/09)
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 20.
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
Installation instructions
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