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935SB: Installation, Start-up, Operating and Service Maintenance Instructions
15. Wipe excess cement from joint. A continuous bead of cement will
be visible around perimeter of a properly made joint.
16. Handle pipe joints carefully until cement sets.
17. Horizontal portions of the venting system shall be supported to
prevent sagging. Space combustion air piping and vent piping
hangers
(Table
19). Support pipes using perforated metal hanging
strap or commercially available hangers or straps designed to
support plastic pipe.
Table 19 – Hanger Spacing
Diameter
PVC Sch
SDR 21 &
40
26
1 1/2-in.
3-ft.
2 1/2-ft.
38-mm
914-mm
762-mm
2-in.
3-ft.
3-ft.
51-mm
914-mm
914-mm
2 1/2-in.
3 1/2-ft.
3-ft.
64-mm
1067-mm
914-mm
3-in.
3 1/2-ft.
3-ft.
76-mm
1067-mm
914-mm
4-in.
4-ft.
3 1/2-ft.
18. Slope the vent and combustion air piping downward towards
furnace. A minimum slope of at least 1/4-in. (6 mm) per linear
ft.(1-in (25 mm) per 4 ft.(1.2 M)) with no sags between hangers is
required. See Caution Box below.
CAUTION
!
FURNACE RELIABILITY HAZARD
Failure to follow this caution may result in nuisance short cycling,
frozen vent termination, and/or no heat.
Slope the vent and combustion air piping downward towards furnace a
minimum of 1/4-in. (6 mm) per linear ft. of pipe.
19. Use appropriate methods to seal openings where combustion air
pipe and vent pipe pass through roof or sidewall.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
DO NOT use cement to join polypropylene venting systems. Follow
the polypropylene venting system manufacturer's instructions for
installing polypropylene venting systems.
Optional Installation of the Vent Pipe
NOTE:
DO
NOT
USE
POLYPROPYLENE VENTING SYSTEMS.
This option provides a disconnect point for the vent pipe. The vent pipe
must be cemented to the plastic vent pipe adapter to maintain a sealed
vestibule (see
Fig.
59).
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Material
Polypropy
ABS
CPVC
lene
3-ft.
3-ft.
3.25-ft.
914-mm
914-mm
1000 mm
3-ft.
3-ft.
3.25-ft.
914-mm
914-mm
1000 mm
3 1/2-ft.
3 1/2-ft.
3.25-ft.
1067-mm
1067-mm
1000 mm
3 1/2-ft.
3 1/2-ft.
3.25-ft.
1067-mm
1067-mm
1000 mm
4-ft.
4-ft.
3.25-ft.
THIS
TECHNIQUE
FOR
VENT PIPE ADAPTER WITH GASKET
INSTALLED ON FURNACE. VENT
PIPE IS CUT FLUSH WITH TOP OF
ADAPTER. PRIME AND CEMENT VENT
PIPE TO ADAPTER. ALLOW TO DRY
BEFORE INSTALLING VENT COUPLING.
VENT PIPE FLUSH WITH ADAPTER
Fig. 59 – Optional Vent Pipe Flush with Adapter
1. Insert a length of vent pipe through the casing into the outlet of the
vent elbow.
2. Slide the plastic vent pipe adapter over the length of the vent pipe
down to the furnace casing. Mark the pipe where it is flush with the
outlet of the adapter.
3. Remove the pipe from the furnace and the adapter and cut off any
excess pipe.
4. Clean and prime the end of the pipe that is flush with the vent
adapter with a primer that is appropriate for the type of pipe being
used.
5. Re-insert the pipe through the casing into the vent elbow.
6. Tighten the clamp around the outlet of the vent elbow. Torque the
clamp to 15 lb-in.
7. Apply cement to the end of the pipe and to the inside of the plastic
vent adapter.
8. Slide the adapter over the vent pipe and align the screw holes in the
adapter with the dimples in the furnace casing.
9. Pilot drill 1/8-in. screw holes for the adapter in the casing and
secure the adapter to the furnace with sheet metal screws.
10. Loosen the clamps on the rubber vent coupling.
11. Slide the end of the coupling with notches in it over the standoffs in
the vent pipe adapter.
12. Tighten the clamp of the coupling over the vent pipe adapter.
Torque the lower clamp around the vent pipe adapter to 15 lb-in.
13. Pilot drill a 1/8-in. hole in the combustion air pipe adapter.
14. Complete the vent and combustion air pipe as shown in "Install the
Vent and Combustion Air Pipe."
!
FOR POLYPROPYLENE VENTING SYSTEMS
When using polypropylene venting systems, all venting materials used,
including the vent terminations, must be from the same manufacturer.
Installing the Vent Termination
Roof Terminations
A roof termination of any type will require a 4-in. (102 mm) flashing for
a 2 in. (50 mm ND) concentric vent or a 5-in. diameter (127 mm)
flashing for a 3-in. (80 mm ND) concentric vent kit. For two-pipe or
single pipe vent systems, a flashing for each pipe of the required
diameter will be necessary.
It is recommended that the flashing be installed by a roofer or competent
professional prior to installing the concentric vent. The terminations can
be installed on a flat or pitched roof.
41
ALIGN NOTCHES IN VENT PIPE
COUPLING OVER STAND-OFF
ON ADAPTER. TORQUE LOWER
CLAMP 15 LB-IN. WHEN REMAINING
VENT PIPE IS INSTALLED, TORQUE
UPPER CLAMP TO 15 LB-IN.
VENT PIPE FLUSH SHOWING COUPLING
NOTICE
A13076
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