Page 9
MagnaTech
BOILERS AND VOLUME WATER HEATERS
commencing within 12” (300 mm) of the top of
the enclosure, shall be permitted. The opening
shall directly communicate with the outdoors
or shall communicate through a vertical or
horizontal duct to the outdoors or spaces that
directly communicate with the outdoors and
shall have a minimum free area of 1 square inch
per 3000 Btu/hr (734 square mm/kW) of the
total input rating of all equipment located in the
enclosure. This opening must not be less than
the sum of the areas of all vent connectors in
the confined space.
Other methods of introducing combustion and
ventilation air are acceptable, providing they
conform to the requirements in the applicable
codes listed above.
In Canada, consult local building and safety
codes or, in absence of such requirements,
follow CAN/CSA B149.
3.1.2 Ducted Combustion Air
The combustion air can be taken through the
wall, or through the roof. Bradford White offers
accessories to use with ducted air systems, as
shown in Table 3.
See Table 4 to select the appropriate diameter
air pipe. When taken from the roof, a field-
supplied rain cap or an elbow arrangement
must be used to prevent entry of rain water.
(See Figure 6).
Use ABS, PVC, CPVC, polypropylene, stainless
steel, or galvanized pipe for the combustion
air intake. (See Table 4) The intake must be
sized per Table 2. Route the intake to the boiler
as directly as possible. Seal all joints. Provide
adequate hangers. The unit must not support
the weight of the combustion air intake pipe.
The maximum equivalent pipe length allowed is
100 feet (30 m).
Each elbow is considered to be 5 feet (1.5m)
When using polypropylene or stainless steel
materials in horizontal duct configurations, a
single elbow must be installed on the end of the
air inlet to act as an outdoor terminal. In vertical
duct applications, two elbows must be installed
on the end of the inlet to act as a vent terminal.
When elbows are use as terminals, appropriate
screens must be installed to prevent blockage.
The elbow(s) required for termination are not
included in the kits sown in Table 3
The connection for the intake air pipe is on the
back panel.
In addition to air needed for combustion, air
shall also be supplied for ventilation, including
air required for comfort and proper working
conditions for personnel. Refer to the applicable
codes.
3.2 Venting
WARNING
Selection of improper vent materials for
installations that are installed in closets, or will be
operated in high ambient temperature levels, may
lead to property damage, personal injury, or death.
WARNING
Failure to use the appropriate vent material,
installation techniques, or glues and sealants
could lead to vent failure causing property
damage, personal injury or death.