Use and Care Manual

8
Installing the water heater
Combustion and Ventilation Air
Proper operation of the water heater
requires air for combustion and
ventilation. Provisions for combustion
and ventilation air must comply with
referenced codes and standards.
When installed in a closet, DO NOT
block or obstruct any of the combustion
air inlet openings located around
the perimeter of the water heater. A
minimum of 1 in. is required between
these combustion air inlet openings and
any obstruction.
NOTICE: If the water heater is installed
in an unconfined space within a building
of conventional frame, masonry or metal
construction, infiltration air is normally
adequate for proper combustion and
ventilation. If the water heater is
installed in a confined space, provisions
for combustion and ventilation air must
be made.
A confined space is one having a volume
of less than 50 cubic feet per 1000 Btuh of
the aggregate input of all appliances within
that space.
The air must be supplied through two
permanent openings of equal area. One is
to be located within 12 in. above the floor
and the other is to be located within 12 in.
from the ceiling.
The minimum net free area of each opening
must not be less than one square inch per
1000 Btuh of the total input rating of all
the appliances in the enclosure (but not less
than 100 square inches), if each opening
communicates with other unconfined areas
inside the building.
Buildings of unusually tight construction
shall have the combustion and ventilation
air supplied from outdoors, or a freely
ventilated attic or crawl space.
If air is supplied from outdoors, directly or
through vertical ducts, there must be two
openings located as specified above and
each must have a minimum net free area of
not less than one square inch per 4000 Btuh
of the total input rating of all the appliances
in the enclosure.
If horizontal ducts are used to communicate
with the outdoors, each opening must have
a minimum net free area of not less than
one square inch per 2000 Btuh of the total
input rating of all the appliances in the
enclosure. If ducts are used, the minimum
dimensions of rectangular air ducts shall
not be less than 3 in.
NOTICE: If the duct openings which
supply combustion and ventilation air
are to be covered with a protective
screen or grill, the net free area
(openings in the material) of the covering
material must be used in determining the
size of the openings. Protective screening
for the openings MUST NOT be smaller
than 1/4 in. mesh to prevent clogging by
lint or other debris.
Corrosive Atmospheres
The air in beauty shops, dry cleaning
establishments, photo processing labs,
and storage areas for liquid and powdered
bleaches or swimming pool chemicals often
contain such halogenated hydrocarbons.
An air supply containing halogenated
hydrocarbons may be safe to breathe,
but when it passes through a gas flame
corrosive elements are released that
will shorten the life of any gas burning
appliance.
Propellants from common spray cans or gas
leaks from A/C and refrigeration equipment
are highly corrosive after passing through
a flame.
The water heater warranty is voided when
failure of the heater is due to operation in a
corrosive atmosphere.
NOTICE: The water heater
should not be installed near
an air supply containing
halogenated hydrocarbons.
Inspect Shipment
Inspect the water heater for possible
damage. Check the markings on the rating
plate of the water heater to be certain the
type of gas supplied corresponds to the
water heater requirements.