A.1.A Category Ii Vent; A.1.B Category Iv Vent; Vent And Air Pipe Material - Bradford White OmniTech BONH1250 Installation And Operation Instructions Manual

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Vent and Air Pipe Sizing (continued)
Route the vent pipe to the heater as directly as possible. Seal all joints and provide adequate hangers as required in
the venting system manufacturer's installation instructions. Horizontal portions of the venting system must be supported
to prevent sagging and may not have any low sections that could trap condensate. The unit must not support the
weight of the vent pipe. Horizontal runs must slope upwards not less than ¼ inch per foot (2 cm/m) from the unit to the
vent terminal. Up to 100 equivalent feet of vent can be used. For each elbow subtract 5 ft of vent length from the total
allowable length of vent pipe.

2.A.1.a Category II Vent

Non-positive pressure vent systems are generally
vertically-terminated. Table 2 gives guidelines for vent
and air pipe sizes, but the draft must be measured to
ensure that it remains between -0.001" w.c. and -0.10"
w.c. at all firing rates. The vent system must be sealed
stainless steel.

2.A.1.b Category IV Vent

Positive pressure vent systems may be either horizontally
or vertically vented. The vent system must be sealed
stainless steel. Approved manufacturers and Category IV
component part numbers are shown in Table 3.
Component
90° Elbow
Pipe
Horizontal Air Inlet
Vertical Termination
Boiler Adapter
Manufacturer
Approved Hanger Straps
Table 3. Manufacturer's Model Numbers (abbreviated
2.A.2

Vent and Air Pipe Material

This unit requires a special venting system. See Table 4 and Table 5 for a list of allowable exhaust vent and combustion
air pipe materials. Refer to venting supplier's instructions for complete parts list and method of installation. The
manufacturers and product lines listed in Table 3 have been tested and authorized to safely operate with this equipment.
Suppliers of stainless steel that are not listed on these tables are not permitted for use with this appliance.
Do not mix venting suppliers and models in venting systems. Failure to comply could result in personal injury, property
damage, or death. Installations must comply with applicable national, state and local codes.
Material
Stainless Steel
Table 4. Required Exhaust Vent Material
Manufacturer Model Numbers (abbreviated)
Selkirk
Safe-T Vent EZ Seal
9x14
9x07
9xTERM
5x00CI
5x01BOI
Distance between Hanger
Straps (Horizontal Run) - 6' MAX
Distance between Hanger
Straps (Vertical Run) - 30' MAX
United States
UL 1738 The vent pipe material must be chosen based upon the intended application
of the boiler or water heater and must be installed according to the vent
manufacturer's installation instructions.
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.
Duravent
FasNSeal
FSELB90xx
FSVLxxxx
FSAIHxx
FSRCx
FSAAUx
Distance between Hanger
Straps (Horizontal Run) - 6' MAX
Distance between Hanger
Straps (Vertical Run) - 12' MAX
Canada
WARNING
NovaFlex
Z Flex
2SVEExx90
2SVEPxxxx
2SVSTEXxx90
25VSRCxx
25VSAxx
Distance between Hanger
Straps (Horizontal Run) - 4' MAX
Distance between Hanger
Straps (Vertical Run) - 16' MAX