2. Install the Vent Pipe and Combustion Air Pipe Runs (from the heater
to near the location selected through the roof).
Use the type of pipe specified in Paragraph 7.2.1.1, page 13.
Comply with requirements in Paragraph 7.2.1.2 and 7.2.1.3, pages 14-
15, when attaching pipes to the heater when installing the condensate
drain connection.
Overall vent length must comply with table in Paragraph 7.2.1.4, page
16.
Make all joints according to the instructions in Paragraph 7.2.1.6, page
16. Extend the runs close to the roof location selected in Step 1 above.
(NOTE: The vent pipe will extend through the roof after the concentric
adapter box is installed. The indoor combustion air pipe will end at the
box.)
Support pipes as required in Paragraph 7.2.1.7, page 17.
3. Cut a clearance hole through the roof for the 8” diameter combus
-
tion air pipe.
Position the concentric adapter box against the inside of the roof. Being
sure that the location and orientation of the box are correct, mark and cut
the hole for the 8” combustion air pipe.
4. Attach the combustion air pipe to the concentric adapter box.
4a)
Determine the length of the 8” outdoor combustion air pipe so that
dimension ”X” in
FIGURE 17
is equal to the roof thickness plus anticipated
snow depth, but does not exceed 48” (1219mm) or have less than 18”
(457mm) of pipe above the roof.
4b)
Attach the combustion air pipe to the collar of the concentric adapter
box with sheetmetal screws. Seal joint and seam with tape or sealant.
5. Attach the concentric adapter box to the underside of the roof.
(Hardware and flashing are field supplied.) On the inside, insert the com
-
bustion air pipe up through the opening, position the box to match the pipe
runs, and attach the brackets to the roof.
6. Determine the length and install the “terminal end” vent pipe.
6a)
Refer to
FIGURE 17
and determine the required length of the continu-
ous section of vent pipe. The length of the vent pipe extending through the
box, through the combustion air inlet pipe, and the height required above
the combustion air inlet air pipe must be one piece of pipe without joints.
Determine the length by adding the requirements:
Starting with at least 6” (152mm) below the box for attaching to the
coupler;
plus
6” (152mm) through the concentric adapter box;
plus
the length of the combustion air pipe;
plus
a
minimum
of 23” (584mm) beyond the top of the combustion
air pipe.
Total is the
minimum length
of the vent pipe section.
NOTE:
A longer vent pipe may be required; see FIGURE 17.
6b
) Install the “terminal end” vent pipe.
Being sure the pipe is in the proper flow direction, slide the end into the box
and out through the combustion air pipe. Position the pipe so that it extends
beyond the combustion air pipe the height determined in
6a)
above. Verify
that the silicone ring is seated properly.
•
•
•
•
•
Form I-UEAS, P/N 221232 R6, Page 25
