Bryant 350AAV Installation, Start-Up, And Operating Instructions Manual page 33

TABLE 10—MAXIMUM ALLOWABLE EXPOSED VENT PIPE LENGTH (FT) WITH AND WITHOUT INSULATION IN WINTER
FURNACE
SIZE
040
060
080
100
120
140
* Pipe length (ft) specified for maximum pipe lengths located in unconditioned spaces. Pipes located in unconditioned space cannot exceed total allowable pipe length as
specified in Table 11.
† Insulation thickness based on R value of 3.5 per in.
ASSEMBLY OF COMBUSTION AIR PIPE (NON-DIRECT
VENT/1-PIPE SYSTEM ONLY)
1. Permanently install perforated disk assembly (factory-
supplied in loose parts bag) in combustion-air elbow using
RTV or by cementing, as shown in Fig. 38. For 120,000
Btuh size units only: separate the 2 halves of perforated disk
assembly and use only the shouldered disk half.
2. Determine the length of straight portion of combustion-air
inlet pipe from Fig. 38.
3. Cut field-supplied 2-in. diameter PVC pipe to length as
determined per Fig. 38.
4. Permanently attach elbow/perforated disk assembly to
straight portion of pipe using RTV or by cementing as
shown in Fig. 38.
ASSEMBLY OF COMBUSTION AIR PIPE (DIRECT VENT-
2-PIPE SYSTEM ONLY)
1. Using Table 11, determine the smallest combustion air
diameter permitted. Pick the larger diameter and use it for
both combustion and vent pipe.
NOTE: Do not count elbows or pipe sections in terminations or
within furnace (All elbows shown in Fig. 42 and Fig. 43 are not to
be counted).
DESIGN TEMPERATURE AMBIENT*
WINTER DESIGN
TEMPERATURE
(°F)
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
20
0
-20
MAX PIPE
WITHOUT
DIAMETER
INSULATION
(IN.)
1.5 51
1.5 28
1.5 16
2 45
2 22
2 10
2 65
2 35
2 20
2 55
2 48
2 30
2.5 70
2.5 47
2.5 28
2.5 40
2.5 40
2.5 38
3 70
3 50
3 28
3 70
3 61
3 37
4 70
4 48
4 23
3 60
3 60
3 44
4 70
4 57
4 30
CAUTION: UNIT MAY NOT OPERATE
Failure to follow this caution may result in incomplete
combusiton, flame disturbance, or flame sense lockout.
When installing combusiton air and vent system of short
pipe length, the smallest allowable pipe diameter must be
used.
NOTE: A 2-in. diameter pipe must be used within furnace casing.
Make all pipe diameter transitions outside furnacec casing per Fig.
39.
2. If required per Table 11, insert perforated disk assembly
(factory-supplied in loose parts bag) in intake housing
where combustion air pipe will be connected. If half disk set
is required, install only shouldered disk half.
ATTACHMENT OF COMBUSTION AIR PIPE
1. Determine location of combustion air intake pipe connec-
tion to combustion air intake housing as shown in Fig. 37
for application.
2. Reposition combustion air intake housing plug fitting in
appropriate unused intake housing connection.
3. Install pipe grommet (factory-supplied in loose parts bag)
into selected furnace casing combustion-air pipe hole.
—33—
WITH 3/8–IN. OR
THICKER INSULATION†
70
70
70
70
70
58
70
70
70
55
55
55
70
70
70
40
40
40
70
70
70
70
70
70
70
70
70
60
60
60
70
70
70