6. Clean and dry all surfaces to be joined.
7. 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.
8. After pipes have been cut and preassembled, apply generous
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.
9. While cement is still wet, twist pipe into socket with 1/4 turn.
Be sure pipe is fully inserted into fitting socket.
10. Wipe excess cement from joint. A continuous bead of cement
will be visible around perimeter of a properly made joint.
11. Handle pipe joints carefully until cement sets.
12. Support combustion-air and vent piping a minimum of every
5 ft (3 ft for SDR-21 or -26 PVC) using perforated metal
hanging strap.
13. Slope combustion-air and vent pipes toward furnace a mini-
mum of 1/4 in. per linear ft with no sags between hangers.
14. Use appropriate methods to seal openings where vent and
combustion-air pipes pass through roof or side wall.
Step 3—Concentric Vent and Combustion-Air
Termination Kit Installation
NOTE: If these instructions differ from those packaged with
termination kit, follow kit instructions.
Combustion-air and vent pipes must terminate outside structure. A
factory accessory termination kit must be installed in 1 of the
installations shown in Fig. 31, 32, 33, 34, or 35. Four termination
kits are available.
1. The 2-in. termination bracket kit is for 1-in., 1-1/2 in., and
2-in. diameter 2-pipe termination systems.
2. The 3-in. termination bracket kit is for 2-1/2 in. and 3-in.
diameter 2-pipe termination systems.
3. The 2-in. concentric vent/air termination kit is for 1-in., 1-1/2
in., 2-in., and 2-1/2 in. diameter pipe systems when single
penetration of wall or roof is desired.
4. The 3-in. concentric vent/air termination kit is for 2-1/2 in. and
3-in. diameter pipe systems when single penetration of wall or
roof is desired.
NOTE: Shaded parts in Fig. 31, 32, 33, 34, and 35 are considered
to be termination. These components should NOT be counted
when determining pipe diameter. Roof termination is preferred
since it is less susceptible to damage, has reduced chances to intake
contaminants, and has less visible vent vapors. (See Fig. 31 or 32.)
Sidewall termination may require sealing or shielding of building
surfaces with a corrosive resistance material due to corrosive
combustion products of vent system.
EXTENDED EXPOSED SIDEWALL PIPES
Sidewall combustion-air and vent pipe terminations may be
extended beyond area shown in Fig. 34 or 35 in outside ambient by
insulating pipes as indicated in Table 6.
1. Determine combustion-air and vent pipe diameters, 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
lengths.
NOTE: Pipe length (ft) specified for maximum pipe lengths
located in unconditioned spaces cannot exceed total allowable pipe
length as specified in Table 5.
TWO-PIPE TERMINATION KIT
1. Determine location for termination.
Consideration of the following should be made when deter-
mining an appropriate location for termination kit.
a. Comply with all clearance requirements as stated in Table
4.
b. Termination kit should be positioned where vent vapors
will not damage plants/shrubs or air conditioning equip-
ment.
c. Termination kit should be positioned so that it will not be
affected by wind eddy (such as inside building corners) or
allow recirculation of flue gases, airborne leaves, or light
snow.
Table 6—Maximum Allowable Exposed Vent Pipe Length (Ft) With Insulation in Winter Design
Temperature Ambient*
UNIT
SIZE
WINTER DESIGN
TEMPERATURE
(°F)
MAX PIPE
DIAMETER
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 4570707070
0 2 25 51 58 70 70
-20 2 1636425160
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 6170707070
0 3 33 65 70 70 70
-20 3 2045526570
120
20 3 7070707070
0 3 40 70 70 70 70
-20 3 2655647070
* 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 5.
† Insulation thickness based on R value of 3.5 per in.
26
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