Reznor CAUA Unit Installation Manual - Manual (Page 18)

Form I-CAUA, P/N 164771 R8, Page 18
FIGURE 10 - Assemble Concentric Adapter Box, Outdoor Combustion Air Pipe, and Double-Wall
Vent Pipe
b. Attach the outside portion of the combustion air pipe to the box. Determine
the length of the combustion air pipe so that dimension ”X” in FIGURE 10 is equal to
the bracket length, plus the roof thickness, plus anticipated snow depth, but does not
exceed 48“ (1219mm) or have less than 18” (457mm) of pipe above the roof. Attach
the inlet air pipe to the collar of the concentric adapter box with sheetmetal screws.
Concentric
Adapter Box
Mounting Brackets
X = length of
combustion air pipe required
through and above the roof.
Height from box to top of inlet air
pipe must not exceed 48” (1219mm).
Minimum height above the roof is
18” (457mm) and must be higher
than anticipated snow depth.
First, attach Combustion Air Pipe and install the
Concentric Box
1) Determine length (X) of pipe (see requirements
on the left).
2) Attach the pipe to the collar on the box.
3) Attach the brackets to the roof.
V
ent Flow
22” (559mm) minimum
Cold Climate NOTE:
In geographic areas where
the design ambient is -10°F
or lower, this minimum
height is 34” (864mm).
Collar for Indoor Portion of
the Combustion Air Pipe
Double-Wall Vent Pipe -
Extend length of double-wall
vent pipe a maximum of 6”
(152mm) below the box.
After box is installed, install Concentric Vent Pipe -
One piece of continuous double-wall pipe must
extend from a minimum of 3” (76mm) above the
outer combustion air pipe to a maximum of 6”
(152mm) below the box. (NOTE: Vent pipe does not
attach to the box; it must be supported.)
1) Calculate height (see requirements on the left).
2) Be sure vent flow marking on pipe is in the right
direction.
3) Slide pipe through the box and the outer inlet air pipe.
4) Attach to vent run no more than 6” (152mm) from the
adapter box. See instructions on pages 11 and 13..
Vent pipe
extending
through the
box and the
combustion
air pipe MUST
be one continuous
piece of double-
wall vent pipe.
A second section
of double-wall pipe
is permitted, joining
the long continuous
piece of vent pipe a
minimum of 3” (76mm)
above the top of the
combustion air pipe.
3” (76mm)
minimum
Outside view with concentric
adapter box attached to
undersideof roof. Install
field-supplied flashing at
roof opening.
Snow Clearance
18” (457mm)
minimum
(NOTE: Maximum
from concentric
adapter box is
48” (1219mm)
FIGURE 11 - Slide
attached Combustion
Air Pipe up through the
Roof
5) Attach the concentric adapter box to the roof. On the inside, insert the
combustion air pipe up through the opening and attach brackets to the roof. (See
FIGURES 10 and 11.) On the outside, flash the combustion air pipe to the roof.
Flashing is field supplied .
6) Determine the length and install the double-wall vent pipe.
a. Determine the minimum length of the continuous section of double-wall vent
pipe (no joints). See FIGURE 10. The vent pipe extending through the box and the
inlet air pipe must be one piece of double-wall vent pipe without joints.
Determine the length by adding the requirements. Starting at the bottom, the
maximum the vent pipe can extend below the box is 6" (152mm); plus 6" (152mm)
through the box; plus length of bracket extending above the box; plus the width
of the roof; plus the height of the outside combustion air pipe above the roof; plus
a minimum of 3" (76mm) beyond the top of the inlet air pipe. Total is the minimum
length of the vent pipe section. If the actual piece of vent pipe is longer, extend it
further above the combustion air pipe. Do not extend it more than 6" (152mm) below
the box.
b. Install the 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 vent pipe so that
6.0 Mechanical
(cont'd)
6.2 Venting and
Combustion Air
(cont'd)
6.2.1.2 VERTICAL Vent Instructions (cont'd)
6.2.1 Venting and Combustion Air Requirements for a Separated
Combustion (cont'd)
Installation Instructions for Vertical Vent/Combustion Air Kit (cont'd)