Bryant 987MA Installation, Start-Up, Operating And Service And Maintenance Instructions page 46

Install the Vent and Combustion Air Pipes
With the furnace installed in the required position, remove the
desired knockouts from the casing. It will be necessary to remove
one knockout for the vent pipe and the other knockout for the
combustion air connection. See Fig. 11.
Use a flat blade screwdriver and tap on the knockout on opposite
sides, where the knockout meets the casing. Fold the knockout
down with duct pliers and work the knockout back and forth until
it is removed. Trim any excess metal from the knockout with tin
snips.
The vent elbow can be rotated to the required location on the
casing if necessary. See Fig. 37. To rotate the vent elbow:
1. Loosen the clamp on the inlet of the vent elbow attached to
the inducer.
2. Rotate the vent elbow to the required position. There are
rounded notches in the vent elbow to align it with the
inducer housing for each orientation.
3. Tighten the clamp around the vent elbow. Torque the clamp
to 15 lb- -in. See Fig. 39- -42.
Installing the Vent Pipe Adapter and Combustion Air
Pipe Adapter
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal
injury or death.
To route the vent pipe and combustion air pipe through the
furnace, the manufacturer supplied kit must be used. Failure
to properly seal the blower compartment from the furnace
vestibule could result in the circulation of carbon monoxide
throughout the structure. The vent pipe and combustion air
pipe must be a continuous pipe while passing through the
blower compartment. Seals supplied in this kit must be
installed per the instructions provided. Follow all
procedures outlined in these instructions.
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.
NOTE: The rubber coupling that attaches to the vent pipe adapter
must be used. The adapter seals the vent pipe to the casing and
reduces the strain on the vent elbow attached to the inducer.
1. Apply the gaskets to the vent pipe and combustion air pipe
adapters. If supplied, remove and discard round center
"slug" from interior of gasket. See Fig. 36.
NOTE: The vent pipe adapter can be distinguished from the inlet
pipe adapter by the absence of an internal pipe- -stopping ring. The
vent pipe can pass through the vent pipe adapter; it cannot pass
through the inlet pipe adapter.
2. Align the screw holes in the plastic vent pipe adapter with
the dimples in the casing.
3. Pilot drill the screw holes for the adapter in the casing and
attach the vent pipe adapter to the furnace with sheet metal
screws
4. Slide the end of the rubber vent coupling with notches in it
over the standoffs on the vent pipe adapter.
5. Insert a length of vent pipe through the coupling into the
outlet of the vent elbow.
6. Tighten the clamp around the outlet of the vent elbow.
Torque the clamp to 15 lb- -in.
NOTICE
The following instructions are for PVC/ABS DWV vent
piping only. DO NOT USE THESE TECHNIQUES FOR
POLYPROPYLENE VENT PIPING SYSTEMS.
polypropylene vent system manufacturer's instructions for
installing polypropylene venting systems.
Install the remaining vent and combustion air pipes as shown
below. It is recommended that all pipes be cut, prepared, and
preassembled before permanently cementing any joint.
1. Working from furnace to outside, cut pipe to required
length(s).
2. De- -burr inside and outside of pipe.
3. Chamfer outside edge of pipe for better distribution of
primer and cement.
4. Clean and dry all surfaces to be joined.
5. Check dry fit of pipe and mark insertion depth on pipe.
6. Insert the vent pipe into the vent elbow.
7. Torque clamp on vent elbow 15 lb- -in.
8. Torque clamp on vent coupling 15 lb- -in.
9. Insert the combustion air pipe into the adapter.
10. Pilot drill a screw hole through the adapter into the combus-
tion air pipe and secure the pipe to the adapter with sheet
metal screws. DO NOT DRILL INTO POLYPROPYLENE
VENT PIPES. Use an optional accessory vent coupling, if
needed.
11. Seal around the combustion air pipe with silicone or foil
tape. SILICONE SEALERS MAY NOT BE APPROPRI-
ATE FOR POLYPROPYLENE VENT SYSTEMS. SEE
POLYPROPYLENE
TURER'S INSTRUCTIONS.
12. 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. DO NOT CEMENT
POLYPROPYLENE FITTINGS.
13. While cement is still wet, twist pipe into socket with 1/4- -in.
turn. Be sure pipe is fully inserted into fitting socket.
14. Wipe excess cement from joint. A continuous bead of ce-
ment will be visible around perimeter of a properly made
joint.
15. Handle pipe joints carefully until cement sets.
16. Horizontal portions of the venting system shall be suppor-
ted to prevent sagging. Support combustion air piping and
vent piping a minimum of every 5 ft. (1.5M)[3 ft. (.91M)
for SDR- -21 or - -26 PVC] using perforated metal hanging
strap or commercially available hangars designed to support
plastic pipe.
17. Prevent condensate from accumulating in the pipes by slop-
ing the combustion air piping and vent piping downward
towards furnace a minimum of 1/4-in. per linear ft. with no
sags between hangers.
18. Complete the vent and combustion air pipe installation by
connecting the concentric vent or by installing the required
46
See the
VENT SYSTEM MANUFAC-