COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS
Combustion Air Requirements:
WARNING
Carbon Monoxide Warning
Water heater must be vented to outdoors.
Vent must be installed by a qualified technician using the local and state codes or, in the absence of local and state codes, the National Fuel Gas Code,
ANSI Z223.1 (NFPA 54) - current edition, and/or the installation instructions.
Examples of a qualified technican include: gas technicians, authorized gas company personel, and authorized service persons.
Failure to so do can result in death or carbon monoxide poisoning.
IMPORTANT: Air for combustion and ventilation must not come from a flammable or corrosive at- mosphere. Any failure due to flammable or corro- sive elements in the atmosphere is excluded from warranty coverage.
The following types of installation (not limited to the following) will require outdoor air for combus- tion due to chemical exposure and may reduce but not eliminate the presence of corrosive chemi- cals in the air:
•beauty shops
•photo processing labs
•buildings with indoor pools
•water heaters installed in laundry, hobby, or craft rooms
•water heaters installed near chemical storage areas
•water softeners
Combustion air must be free of
Combustion and ventilation air requirements are determined 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
Table 1:
| Minimum Square | Typical Room | |
BTUH Input | Feet with | ||
with 8’ Ceiling | |||
| 8’ Ceiling | ||
|
| ||
30,000 | 188 | 9 x 21 | |
45,000 | 281 | 14 x 20 | |
60,000 | 375 | 15 x 25 | |
75,000 | 469 | 15 x 31 | |
90,000 | 563 | 20 x 28 | |
105,000 | 657 | 20 x 33 | |
120,000 | 750 | 25 x 30 | |
135,000 | 844 | 28 x 30 |
IMPORTANT:
•The area must be open and be able to provide the proper air requirements to the water heater. Areas that are being used for storage or contain large objects may not be suitable for water heater installation.
•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 home construction usually requires supplying outside air into the water heater area.
•Room exhaust fans may effect air requirements.
Confined Space: For the correct and proper operation of this water heater, ample air must be supplied for the combustion, ventilation, and dilu- tion 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.
The size of each opening (free area) is deter- mined 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 rating plate. Additional air can be provided by two methods:
1.All air from inside the building.
2.All air from outdoors.
12” MAXIMUM
CLOSET
OR
OTHER
CONFINED
PERMANENT
SPACE
Unconfined Space: A water heater in an uncon- fined 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 mini- mum square footage (area) required for various BTUH inputs.
OPENINGS TO
THE OUTSIDE OR
ADDITIONAL
ROOMS WITHIN
THE BUILDING
12” MAXIMUM
Figure 2.
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