Bryant 345MAV - Manual (Page 27)

WARNING: Vent pipe must be installed and fully
seated against inducer housing. Clamp must be tightened
to prevent any condensate leakage. Failure to follow this
warning could result in electrical shock, fire, personal
injury, or death.
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
VENT EXTENSION PIPE
Some furnaces are supplied with a PVC vent extension pipe
(2-in. diameter by 12-in. long). This pipe has a built-in
channel to assist vent condensate disposal. When this vent
extension pipe is supplied, it must be used to connect the
field vent pipe to furnace inducer housing on ALL upflow
and downflow applications.
NOTE: See label on vent extension pipe for proper installation.
This pipe may be shortened if an elbow is used to connect vent
extension tube to field-installed vent pipe.
5. Working from furnace to outside, cut pipe to required
length(s).
6. Deburr inside and outside of pipe.
7. Chamfer outside edge of pipe for better distribution of
primer and cement.
8. Clean and dry all surfaces to be joined.
9. Check dry fit of pipe and mark insertion depth on pipe.
NOTE: It is recommended that all pipes be cut, prepared, and
preassembled before permanently cementing any joint.
10. After pipes have been cut and preassembled, apply gener-
ous layer of cement primer to pipe fitting socket and end of
pipe to insertion mark. Quickly apply approved cement to
end of pipe and fitting socket (over primer). Apply cement
in a light, uniform coat on inside of socket to prevent
buildup of excess cement. Apply second coat.
11. While cement is still wet, twist pipe into socket with 1/4
turn. Be sure pipe is fully inserted into fitting socket.
12. Wipe excess cement from joint. A continuous bead of
cement will be visible around perimeter of a properly made
joint.
13. Handle pipe joints carefully until cement sets.
14. Support vent piping a minimum of every 5 ft (3 ft for
SDR-21 or -26 PVC) using perforated metal hanging strap.
15. Slope vent pipe toward furnace a minimum of 1/4 in. per
linear ft with no sags between hangers.
TABLE 4—MAXIMUM ALLOWABLE VENT PIPE LENGTH (FT) Continued
ALTITUDE UNIT SIZE
VENT PIPE
DIAMETER (IN.)
NUMBER OF 90° ELBOWS
1 2 3 4 5 6
9001 to 10,000†
024040
036040 1-1/2 42 37 32 27 25 20
2 57 55 53 51 49 47
024060
036060
048060
2 45 40 38 33 31 29
036080
048080
060080 2 30 25 14 9 7 NA
2-1/2 57 55 53 51 49 47
048100
060100 2-1/2 21 13 5 NA NA NA
3 54 49 44 39 34 29
060120 3* 39 37 35 33 31 29
* Wide radius elbow.
† Vent sizing for Canadian installations over 4500 ft (1370 m) above sea level are subject to acceptance by the local authorities having jurisdiction.
NA—Not Allowed; pressure switch will not make.
NOTES:
1. Do not use pipe size greater than those specified in table or incomplete combustion, flame disturbance, or flame sense lockout may occur.
2. Assume two 45° elbows equal one 90° elbow. Long radius elbows are desirable and may be required in some cases.
3. Elbows and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
4. The minimum pipe length is 5 ft for all applications.
TABLE 5—MAXIMUM ALLOWABLE EXPOSED VENT PIPE LENGTH (FT) WITH INSULATION IN
WINTER DESIGN TEMPERATURE AMBIENT*
UNIT
SIZE
WINTER DESIGN
TEMPERATURE
(°F)
MAX PIPE
DIAMETER
(IN.)
INSULATION THICKNESS (IN.)†
0 3/8 1/2 3/4 1
040
20 1-1/2 31 56 63 70 70
0 1-1/2 16 34 39 47 54
-20 1-1/2 9 23 27 34 39
060
20 2 45 70 70 70 70
0 2 25 51 58 70 70
-20 2 16 36 42 51 60
080
20 2-1/2 55 70 70 70 70
0 2-1/2 31 61 69 70 70
-20 2-1/2 20 43 49 61 70
100
20 3 61 70 70 70 70
0 3 33 65 70 70 70
-20 3 20 45 52 65 70
120
20 3 70 70 70 70 70
0 3 40 70 70 70 70
-20 3 26 55 64 70 70
* 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 4.
† Insulation thickness based on R value of 3.5 per in.
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