Ventilation And Combustion Air Supply - Rheem PVG Installation, Operation And Service Manual

GENERAL INFORMATION
WARNING
THIS WATER HEATER AND ANY OTHER FUEL BURNING APPLIANCE
MUST BE PROVIDED WITH ENOUGH FRESH AIR FOR PROPER
VENTILATION OF THE FLUE GASES. MOST HOMES WILL REQUIRE
THAT OUTSIDE AIR BE SUPPLIED INTO THE WATER HEATER AREA.
FAILURE TO DO SO CAN RESULT IN EXPLOSION, FIRE, PROPERTY
DAMAGE, CARBON MONOXIDE POISONING, PERSONAL INJURY OR
DEATH.
Adequate facilities for providing air for combustion and ventilation must be
provided in accordance with the "National Fuel Gas Code", ANSI Z223.1-
Latest Edition, NFPA 54 or the applicable provisions of the local building
codes.
IMPORTANT: Air for combustion and ventilation must not come from a
corrosive atmosphere. Any failure due to corrosive elements in the
atmosphere is excluded from warranty coverage.
The following types of installation (but not limited to the following) will
require outdoor air for combustion due to chemical exposure and may
reduce but not eliminate the presence of corrosive chemicals in the air:
• Beauty shops
•
Photo processing labs
•
Commercial buildings
•
Buildings with indoor pools
•
Water heaters installed in laundry, hobby or craft rooms.
•
Water heaters installed near chemical storage areas
Combustion air must be free of acid-forming chemicals such as sulfur,
fluorine, and chlorine. These elements are found in aerosol sprays,
detergents, bleaches, cleaning solvents, air fresheners, paint and varnish
removers, refrigerants, and many other commercial and household
products. When burned, vapors from these products form highly corrosive
acid compounds. These products should not be stored near the water
heater or air inlet.
Combustion and ventilation air requirements are de-termined by the location
of the water heater. The water heater may be located in either an open
(unconfined) area or in a confined area or small enclosure such as a closet
or small room. Confined spaces are areas with less than 50 cubic feet
for each 1,000 BTUH of the total input for all gas-using appliances.
WATER HEATER LOCATION - UNCONFINED SPACE
A water heater in an unconfined space uses indoor air for combustion and
requires at least 50 cubic feet for each 1,000 BTUH of the total input
for all gas appliances. The table below shows a few examples of the
minimum square feet required for various BTUH inputs.
BTUH MIN. SQ. FEET
INPUT WITH 8' CEILING
30,000 188
45,000 281
60,000 375
75,000 469
90,000 563
105,000 657
120,000 750
135,000 844
Areas which are being used for storage or contain large space consuming
items may not be suitable for water heater installation. The area must be
open and be able to provide the proper air requirements to the water
heater.

VENTILATION AND COMBUSTION AIR SUPPLY

TYPICAL ROOM SIZE
WITH 8' CEILING
9 X 21
14 X 20
15 X 25
15 X 31
20 X 28
20 X 33
25 X 30
28 X 30
IMPORTANT: Water heaters installed in open spaces in buildings with
unusually tight construction may still require outdoor air to function
properly. In this situation, outside air openings should be sized the same as
for a confined space.
MODERN CONSTRUCTION USUALLY REQUIRES SUPPLYING OUTSIDE AIR
INTO THE WATER HEATER AREA.
CONSULT THE LOCAL CODES OF YOUR AREA FOR
VENTILATION AND COMBUSTION AIR REQUIREMENTS.
For the correct and safe operation of this water heater, ample air must be
supplied for the combustion, ventilation and dilution of flue gases. Small
enclosures and confined areas must have two permanent openings so
that sufficient fresh air can be drawn from outside of the enclosure. One
opening shall be within 12 inches of the top and one within 12 inches
of the bottom of the enclosure as shown in Figure 4 below.
The size of each opening (free area) is determined by the total Btuh input of
all gas utilization equipment (i.e. water heaters, furnaces, clothes dryers,
etc.) and the method by which the air is provided. The Btuh input can be
found on the water heater data plate. Additional air can be provided by two
methods:
1. All air from inside the building.
2. All air from outdoors.
ALL AIR FROM INSIDE THE BUILDING
When additional air is to be provided to the confined area from additional
room(s) within the building, the total volume of the room(s) must be of
sufficient size to properly provide the necessary amount of fresh air to the
water heater and other gas utilization equipment in the area. If you are
unsure that the structure meets this requirement, contact your local gas
utility company or other qualified agency for a safety inspection.
Each of the two openings shall have a minimum free area of 1 square inch
per 1,000 Btuh of the total input rating of all gas utilization equipment in
the confined area, but not less than 100 square inches (Figure 5).
CAUTION
AIR CANNOT BE TAKEN FROM AREAS THAT CONTAIN NEGATIVE
PRESSURE PRODUCING DEVICES SUCH AS FIREPLACES, EXHAUST
FANS, AND AIR CIRCULATION SYSTEMS.
SPECIFIC
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