Use and Care Manual

LP-436 Rev. 5.2.18
9
3) When communicating with the outdoors through horizontal
ducts, each opening shall have a minimum free area of one (1)
square inch per 2,000 BTU/H (11 cm
2
/kW) of the total input rating of
all gas appliances in the enclosure. See Figure 6.
Figure 6 - Conned Space - Communicating Outdoors through
Horizontal Ducts
In Canada (refer to CAN/CSA B149.1)
a. All Air From Inside the Building
The conned space shall be provided with one opening of one (1)
square inch per 1,000 BTU/H (22 cm
2
/kW) communicating directly
with one or more rooms of sucient volume, so that the combined
volume of all spaces meets the criteria for an unconned space for
all the appliances installed in that conned space. See Figure 7.
When ducts are used, they shall be of the same cross-sectional area
as the free area of the openings to which they connect. The mini-
mum short side dimension of rectangular air ducts shall not be less
than three (3) inches (7.6 cm).
b. All Air From Outdoors
An air supply shall be provided with one opening that communicates
directly with the outdoors by means of a duct. This duct shall be
sized according to CAN/CSA B149.1 and terminate within one (1)
foot above and within two (2) feet horizontally from the burner level
of the appliance having the largest input. See Figure 8.
Figure 7 - Conned Space - All Air from Inside Building
Figure 8 - Conned Space - All Air from Outdoors through Duct
3. Louvers and Grilles
In calculating free area for ventilation and combustion air supply
openings, consideration must be given to the blocking eect of
louvers, grilles, or screens protecting the openings. Screens must not
be smaller than ¼” (6.4 mm) mesh. If the free area through a particular
design of louver or grille is known, it should be used in calculating the
size of opening required to provide the free area specied. If the design
and free area is not known, it may be assumed the wood louvers and
grilles will allow 20-25% free area and metal louvers and grilles will
allow 60-75% free area. Louvers and grilles must be installed in the
open position or interconnected with the water heater so that they are
opened automatically during water heater operation.
4. Corrosive Atmospheres
If this water heater is to be installed in a beauty shop, barber shop,
photo processing lab, dry cleaning establishment, a building with an
indoor pool, or near a chemical storage area, it is imperative that the
combustion and ventilation air be drawn from outside these areas.
These particular environments contain products such as aerosol sprays,
detergents, bleaches, cleaning solvents, refrigerants, and other volatile
compounds that, in addition to being highly ammable, become
highly corrosive acid compounds when burned. Exposure to such
compounds can be hazardous and lead to premature product failure.
Should the water heater fail due to exposure to such a corrosive
atmosphere, the warranty is void.
D. Venting
When installing the venting system, make sure to follow all local
codes, or, in the absence of local codes, National Fuel Gas Code, ANSI
Z223.1/NFPA 54 in the United States, or CAN/CSA B149.1, National
Gas and Propane Installation Code in Canada. Never operate the
water heater unless it is properly ventilated to the outdoors and has
adequate air supply for proper operation. Failure to properly install
the venting system could result in property damage, personal injury,
or death.
1. Automatic Flue Damper / Drafthood Assembly
The ue damper/drafthood assembly has been shipped from the
factory in a separate box attached to this water heater. Before installing
the ue damper/drafthood assembly, verify that it is the correct model
for this water heater (the CG125N73 uses a 5” ue damper, all other 73
gallon models use a 6” ue damper; CG250N65 uses a 7” ue damper, all
other 65 gallon models use an 8” ue damper). If the wrong assembly
has been shipped or is missing completely, immediately contact the
dealer where the water heater was purchased. Never operate this
water heater without the manufacturer’s ue damper/drafthood
assembly installed.