Bryant Bruant 4 Way Gas 355AAV - Manual (Page 40)

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11. Horizontal portions of the venting system shall be
supportive to prevent sagging support. Support combustion
air piping (if applicable) and vent piping a minimum of
every 5 ft. (1.5 M)(3 ft. (.91 M) for SDR--21 or --26 PVC)
using perforated metal hanging strap.
12. Slope combustion air piping (if applicable) and vent piping
downward towards furnace a minimum of 1/4 in. (6 mm)
per linear ft. with no sags between hangers.
13. Horizontal portions of the venting system shall be installed
so as to prevent the accumulation of condensate.
14. Use appropriate methods to seal openings where
combustion air pipe (if applicable) and vent pipe pass
through roof or sidewall.
EXAMPLE
An 100--14 size furnace located in Indianapolis, elevation 650
ft. (198 M) above sea level, could be installed as either a direct
vent/2--pipe system that requires 3 elbows and 28 ft. (8.5 M)
of vent pipe, along with 5 elbows and 34 ft. (10.3 M) of
combustion--air pipe OR a non--direct vent/1--pipe system that
requires 3 elbows and 28 ft. (8.5 M) vent pipe.
For a direct vent/2--pipe system, Table 11 indicates this
application would allow a 2--in. (51 mm) diameter vent pipe,
but require a 2--1/2 in. (64 mm) diameter combustion air pipe.
According to Table 11, 2--in. (51 mm) diameter pipe is good
for 30 ft. (9.1 M) with 3 elbows, but only 20 ft. (6.1 M) with 5
elbows. Therefore, 2--1/2 in. (64 mm) diameter pipe must be
used for both vent and combustion air pipes since larger
required diameter must always be used for both pipes.
For a non--direct vent/1--pipe system, Table 11 indicates that
this application would allow a 2--in. (51 mm) diameter vent
pipe. If same installations were in Albuquerque, elevation
5250 ft. (1600 M) above sea level:
For a direct vent/2--pipe system, Table 11 indicates that 2--1/2
in. (64 mm) diameter vent pipe and combustion--air pipe are
required.
For a non--direct vent/1--pipe system, Table 11 indicates that
2--1/2--in. (64 mm) diameter vent pipe is required. If same
applications are to be installed at 5001-- to 6000 ft. (1524 --
1829 M) elevation:
For a direct vent/2--pipe system, 2--in. (51 mm) pipe is only
good for 23 ft. (7.0 M) (with 3 elbows) and 13 ft. (3.9 M)
(with 5 elbows). Therefore, 2--1/2 in. (64 mm) diameter
combustion air and vent pipe must be used.
For a non--direct vent/1--pipe system, a 2--in. (51 mm)
diameter pipe is only good for 23 ft. (7.0 M) with 3 elbows. A
2--1/2--in. (64 mm) diameter vent pipe must be used.
VENT TERMINATION
General
Combustion--air (direct vent/2--pipe system only) and vent pipe
must terminate outside structure, either through sidewall or roof.
For vent termination clearance, refer to Table 8 for Direct
Vent/2--Pipe system and Table 9 for Non--direct Vent/1--Pipe
system. For exterior piping arrangements, refer to Fig. 43 for
Direct Vent/2--Pipe system and Fig. 44 for Non--Direct/1--Pipe
system.
Roof termination is preferred since it is less susceptible to damage
or contamination, and it has less visible vent vapors. Sidewall
termination require sealing or shielding of building surfaces with a
corrosive resistance material due to corrosive combustion products
of vent system.
NOTE: (Direct Vent/2--Pipe system ONLY) A factory accessory
termination kit MUST be used. See section “Vent Termination Kit
(Direct Vent/2--Pipe System Only)” in this instruction.
When determining appropriate location for termination, consider
the following guidelines:
1. Comply with all clearance requirements stated in Table 8 or
Table 9 per application.
2. Termination or termination kit should be positioned where
vent vapors will not damage plants/shrubs or air
conditioning equipment.
3. Termination or termination kit should be positioned so that
it will not be affected by wind eddy, such as inside building
corners, nor by recirculation of flue gases, airborne leaves,
or light snow.
4. Termination or termination kit should be positioned where it
will not be damaged by or subjected to foreign objects such
as stones, balls, etc.
5. Termination or termination kit should be positioned where
vent vapors are not objectionable.
Extended Exposed Sidewall Pipes
Sidewall combustion air pipe termination (direct vent/2--pipe
system only) and vent pipe termination may be extended beyond
area shown in Fig. 43 or in Fig. 44 per application in outside
ambient by insulating pipe as indicated in Table 10.
1. Determine combustion air pipe diameter (direct vent/2--pipe
system only) and vent pipe diameter, as stated above, using
total pipe length and number of elbows.
2. Using winter design temperature (used in load calculations),
find appropriate temperature for your application and
furnace model.
3. Determine required insulation thickness for exposed pipe
length(s).
NOTE: Pipe length (ft. / M) specified for maximum pipe lengths
located in unconditioned spaces cannot exceed total allowable pipe
length as specified in Table 11.
Vent Termination Kit (Direct Vent/2--Pipe System
Only)
NOTE: Always refer to the instructions in termination kit for the
latest version.
Combustion air and vent pipes MUST terminate outside structure.
A factory accessory termination kit must be installed as shown in
Table 12. There are four options of vent/combustion air
termination kits available as shown in Table 12.
NOTE: Combustion air pipe must have the same diameter as vent
pipe.
Concentric Vent/Combustion Air Termination Kit
(Direct Vent/ 2--Pipe System Only)
Determine an appropriate location for termination kit using the
guidelines provided in section “Vent Termination: General” in this
instruction.
1. Cut one 4--in. (102 mm) diameter hole for 2--in. (51 mm)
kit, or one 5--in. (125 mm) diameter hole for 3--in. (76 mm)
kit.
2. Loosely assemble concentric vent/combustion air
termination components together using instructions in kit.
3. Slide assembled kit with rain shield REMOVED through
hole.
NOTE: Do not allow insulation or other materials to accumulate
inside of pipe assembly when installing it through hole.
Roof terminations–Locate assembly through roof to appropriate
height as shown in Fig. 43.
Sidewall terminations--Locate assembly through sidewall with
rain shield positioned no more than 1--in. (25 mm) from wall as
shown in Fig. 43.
4. Disassemble loose pipe fittings. Clean and cement using
same procedures as used for system piping.
5. Check required dimensions as shown in Fig. 43.
355A