HeatStation™ CONDENSING WATER BOILER
17
34-1161 05/17
7
COMBUSTION AND VENTILATION AIR
Provisions for adequate combustion and ventilation air to the mechanical room must be in accordance with Section
“Air for Combustion and Ventilation” in the latest edition of the NFPA 54 National Fuel Gas Code, ANSI Z223.1 and/or
CAN/CSA B149, Installation Codes or applicable provisions of the local building codes. Any method addressed in
NFPA 54 National Fuel Gas Code sectio
n “Air for Combustion and Ventilation is acceptable and several are outlined
below.
7.1 Equipment Located In Confined Spaces
Equipment located in confined spaces requires two openings, one commencing within 12
"
(30.5 cm) from the top of
the enclosure/room and one commencing within 12
"
from bottom of the enclosure/room to assure adequate
combustion air and proper ventilation. The total input of all gas utilization equipment installed in the room must be used
to determine the required minimum air volume needed for combustion, ventilation and dilution of flue gasses. Also
consider makeup air requirements from other equipment within the mechanical room or other rooms that are pressure
connected with the mechanical room. Some examples of other makeup air requirements are from kitchen exhaust
hoods, clothes dryers, powered exhaust fans, etc.
When using room air, it is important to ensure the combustion air vent is clear of obstructions, protected from accidental
blockage, and protected from airborne debris. A standard vent cap can be used.
All Air From Outdoors:
Each opening requires a minimum free area of 1 square inch
per 4000 Btu/hr of the total input rating of all appliances
in the enclosure, if directly communicating with the outdoors or communicating to the outdoors through vertical
ducts.
Each opening requires a minimum free area of 1 square inch
per 2000 Btu/hr of the total input rating of all appliances
in the enclosure, if communicating with the outdoors through horizontal ducts.
All Air From Inside The Building:
Follow the requirements of NFPA 54 National Fuel Gas Code, ANSI Z223.1
section “Indoor Combustion Air.”
Combination Of Air From The Indoors And From The Outdoors:
Follow the requirements of NFPA National Fuel Gas Code, ANSI Z223.1
section “Combination Indoor and Outdoor
Combustion Air.”
From Outdoors Through One Opening:
Follow the requirements of NFPA National Fuel Gas Code, ANSI Z223.1
section “One Permanent Opening Method.”
Remote Air Intake System:
This unit may be installed with a remote air intake system which uses a make-up air duct to draw combustion air
directly from outdoors.
Combustion air piping must be supported to prevent transferring any load (weight or twisting
moment) on the appliance remote air connection. Load imparted by improperly supported and constrained remote
air piping can damage the burner, which could prevent the boiler from operating. Failure to properly support the
combustion air supply piping can result in unwarranted damage to the boiler.
WARNING: Adequate clean combustion air must be provided to the appliance. The appliance must never
operate under a negative pressure. Particular care must be taken when exhaust fans, compressors, air
handling units, etc. may rob air from the appliance. The combustion air supply must be completely free of any
chemicals or fumes, which may be corrosive to the appliance. Some common chemical fumes to avoid are
fluorocarbons and other halogenated compounds, most commonly present as refrigerants or solvents, such
as Freon, trichloroethylene, perchlorethylene, chlorine, etc. These chemicals, when in contact with the
equipment or when burned, form acids which quickly attack the tubes, flue collector, stack and other appliance
and auxiliary equipment. Failure to provide adequate clean combustion air or operating under negative
pressure can cause premature, unwarranted product failure or unsafe operation producing carbon monoxide
that could escape into the building. Exposure to carbon monoxide can lead to personal injury or death.
