Bosch Appliances GWH 2400 ES NG Water Heater User Manual

6 720 608 782
Installation instructions
signage installed in accordance with the provisions of
248 CMR 5.08(2)(a)1 through 4.
(b) 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;
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.
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.
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
(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.
3.4 Combustion air requirements
Twin pipe
The GWH 2400 ES 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. 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. 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 terminator. See Fig. 10
Letter I, page 10.
The maximum length of the combustion air inlet
is 26 feet with one elbow. Subtract 2.5 feet for
each additional 90° elbow and 1.25 feet for each
additional 45° elbow. Maximum number of
elbows permitted is 3.
Single pipe
Note: This appliance requires 8750 cubic feet of
available combustion air, or a minimum of 1094
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 outside (see twin pipe system 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
If a single pipe installation is utilized, follow guidelines
Warning: 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
Warning: When installed in an
environment where corrosive chemicals
or dirty air are present the twin pipe
system is required.
Warning: Vent terminations must
prevent rain from entering the
combustion air and exhaust vent piping.