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SSCBL-RPBL-IOM (10-22) 149159-C
Figure 19. Joining Double-Wall (Type B) Pipe to Vent Terminal Cap (Horizontal or Vertical)
STEP 1
Place a continual 3/8” bead of silicone sealant
around the circumference of the vent cap col-
lar. This will prevent any water inside the vent
cap from running down the double-wall pipe.
Do STEP 2 immediately following STEP 1.
STEP 2
Insert the collar on the vent cap inside the
inner wall of the double-wall pipe. Insert
as far as possible. Add additional silicone
sealant to fully close any gaps between
the vent cap and the double wall pipe.
This is necessary to prevent water from
entering the double wall pipe.
Secure the vent cap to the double-wall pipe by drilling and inserting a 3/4” long
sheetmetal screw into the vent cap collar. Do not overtighten screw.
STEP 3
STEP 1
On the taper-type reducer, place a con-
tinual 1/4” bead of silicone sealant
around the circumference.
STEP 2
Insert the collar of the reducer into the
inner pipe of the double-wall pipe until
the bead of sealant contacts the inner
pipe creating a sealed joint.
STEP 3
Spaced equally around the double-wall
pipe, drill three small holes below the
sealant ring. Insert 3/4 inch long
sheetmetal screws to secure the joint. Do
not overtighten screws.
5" I.D.
Double-
Wall
Pipe
6" to 5" or
7" to 5"
Taper-
Type
Reducer
Do STEP 2
immediately
following
STEP 1.
Figure 20. Joining Double-Wall (Type B) Pipe to Single-Wall or Category III Vent Pipe
Using Tapered Reducer
Specific Venting Requirements: Support
Support horizontal runs every six feet (1 .8 meters) . Support vertical runs of Type B double-wall or Category III vent
pipe in accordance with the requirements of the pipe manufacturer . Support single-wall vertical pipe in accordance
with accepted industry practices . Do not rely on the heater or the adapter box for support of either horizontal or
vertical pipes . Use noncombustible supports on vent pipe .
NOTE: The double-wall vent terminal pipe does not attach to the concentric adapter box and must
be supported during installation.
