Air For Combustion & Ventilation - Crown Boiler AWR Series Installation Instructions Manual

• This boiler is not designed for use in a space that is depressurized relative to the outdoors. Operating this
boiler in a depressurized space may cause severe personal injury or death.
• INSUFFICIENT COMBUSTION AIR SUPPLY may result in the production and release of deadly Carbon
Monoxide (CO) into the home.
• PROVIDE ENOUGH AIR to ventilate the boiler room, and sustain combustion. Ignition failure, overheating,
fire, carbon monoxide, and spillage of flue gases may result from poor air supply.
• Do not install this boiler in areas where it will draw combustion air from areas where chemicals, such as
bleaches, fabric softeners, paints, cleaners, refrigerants, and cat boxes are used or stored. Do not draw
combustion air containing large amounts of dust such as that generated by dry wall construction or
woodworking. Failure to observe this warning could result in objectionable odors, severe boiler damage,
personal injury or loss of life.
Sufficient fresh air must be supplied for combustion, ventilation, and flue gas dilution. Provisions for an adequate fresh air
supply must be made in accordance with local codes, or in the absence of such codes, the National Fuel Gas Code (NFPA 54/
ANSI Z223.1). In Canada, refer to the Natural Gas and Propane Installation Code (CAN/CSA 149.1).
The National Fuel Gas Code describes three basic ways to supply this boiler with adequate fresh air:
Indoor Combustion Air – Combustion air is drawn into the boiler room from other parts of the building and from the outdoors
through natural infiltration (cracks under doors, etc). This method can not be used in all cases – see discussion below.
Outdoor Combustion Air – Combustion air is brought directly into the boiler room from outdoors through ducts or grills sized
and installed specifically for this purpose.
Mechanical Combustion Air Supply – Combustion air is brought into the room from outdoors using a blower system that is
engineered specifically for this purpose.
Each of the above methods is described in more detail in the following sections. The National Fuel Gas Code also describes
some acceptable variations on these techniques that do not appear here.
1) Total the input of all appliances in the boiler room in thousands of BTU/hr.
2) Find the volume of the boiler room in cubic feet:
Volume (ft ) = Length (ft) x Width (ft) x Height (ft)
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If the boiler room adjoins another room and there is no door present between these two rooms, add the volumes of the
rooms together. Repeat for any other connected rooms which do not have doors. Do not add the volume of two rooms
separated by a door even if that door is "always left open".
3) Divide the volume obtained in Step 2 by the input calculated in Step 1.
4) If the result is at least 50 ft
tration should provide adequate fresh air into the boiler room.
5) If the result is less than 50 ft
near the ceiling. The top edge of the upper opening must be within 6" of the ceiling and the bottom edge of the lower
opening must be within 6" of the floor (Figure 5.1):
• Each opening must have a free area of 1 square inch per 1000 BTU/hr input of all gas burning appliances in the
boiler room. The minimum opening dimension is 3 inches. Minimum opening free area is 100 square inches per
opening.
• If the total volume of both the boiler room and the room to which the openings connect is less than 50 cubic feet
V Air for Combustion and Ventilation
!
WARNING
Using the Indoor Combustion Air Method
per 1000BTU/hr, and neither of the conditions described in (6) below are met, normal infil-
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per 1000BTU/hr, provide two openings into the boiler room, one near the floor and one
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