6
A)
When communicating directly with the outdoors,
each opening shall have a minimum free area of one
(1) square inch per 4,000 BTUH (5.5 cm
2
/kW) of the
total input rating of all gas appliances in the enclosure
(
see Figure 5
).
B)
When communicating with the outdoors through
vertical ducts, each opening shall have a minimum
free area of one (1) square inch per 4,000 BTUH
(5.5 cm
2
/kW) of the total input rating of all gas appli-
ances in the enclosure (
see Figure 6
).
C)
When communicating with the outdoors through
horizontal ducts, each opening shall have a mini-
mum free area of one (1) square inch per 2,000
BTUH (11.0 cm
2
/kW) of the total input rating of
all gas appliances in the enclosure (
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 minimum short side dimension
of rectangular air ducts shall not be less than three (3)
inches (7.62 cm).
Louvers and Grilles
In calculating free area for ventilation and com-
bustion air supply openings, consideration must be
given to the blocking effect of louvers, grilles, or
screens protecting the openings. Screens must not
be smaller than
1
/
4
inch (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-
fied. If the design and free area is not known, it may
be assumed that 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 interconnect-
ed with the water heater so that they are opened
automatically during water heater operation.
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, refrige rants, and other
volatile compounds that, in addition to being highly
flammable, 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.
INSTALLATION INSTRUCTIONS
Espace restreint
Évent menant
à l’extérieur
Évent menant
à l’extérieur
Entrée d’air du
sous-sol
Évent de fondation
Sortie d’air au grenier
Sortie d’air au grenier
Conduite d’air extérieur
Sortie
Entrée
Conduite d’entrée d’air
Espace
restreint
Espace
restreint
Espace
restreint
Installez
au dessus
de l’isolation
Ouverture
permanente
po
po
po
po
po
po
po
po
Figure 7
Espace restreint
Évent menant
à l’extérieur
Évent menant
à l’extérieur
Entrée d’air du
sous-sol
Évent de fondation
Sortie d’air au grenier
Sortie d’air au grenier
Conduite d’air extérieur
Sortie
Entrée
Conduite d’entrée d’air
Espace
restreint
Espace
restreint
Espace
restreint
Installez
au dessus
de l’isolation
Ouverture
permanente
po
po
po
po
po
po
po
po
Figure 6
Espace restreint
Évent menant
à l’extérieur
Évent menant
à l’extérieur
Entrée d’air du
sous-sol
Évent de fondation
Sortie d’air au grenier
Sortie d’air au grenier
Conduite d’air extérieur
Sortie
Entrée
Conduite d’entrée d’air
Espace
restreint
Espace
restreint
Espace
restreint
Installez
au dessus
de l’isolation
Ouverture
permanente
po
po
po
po
po
po
po
po
Figure 5
