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A single-wall vent pipe used as a vent connector in resi-
dential or commercial applications, or as a vertical vent in
commercial applications, must have all seams and joints
sealed with pressure-sensitive aluminum tape or silicone
rubber sealant. Aluminum tape must meet the provisions
of SMACNA AFTS-100-73 Standards. The aluminum tape
must have a temperature rating of 400°F (204°C). Silicone
rubber sealant must have a temperature rating of 482°F
(250°C), i.e., Dow Corning RTV-736 or equivalent. All
joints must be secured with at least two corrosion-resistant
screws. All joints must be checked for gas tightness after
installation. Single-wall vent pipe used as vertical vent in
commercial applications must not pass through any attic,
interior wall, concealed space, or oor.
VERTICAL VENTS USING METAL VENT PIPE -
COMMERCIAL AND RESIDENTIAL INSTALLATIONS
These compact unit heaters are listed as Category 1
appliances for vertical vent installations.
1 - These unit heaters are to be used with NFPA- or
ANSI-approved chimneys or U.L.-listed type B-1
gas vents, or listed chimney lining systems for gas
venting where applicable, as well as the modications
and limitations listed in gure 3. Seal single-wall vent
material according to General Recommendations
and Requirements section.
2 - The vent connector shall be 4” (102mm) diameter on
30K, 45K, 60K, 75K, 090K, 105K, 125K, and 150K
Btuh units; 5” (127mm) diameter on 175K, 200K,
250K, & 300K Btuh units; 6” (152mm) on 350K &
400K Btuh units. On 175-400 units, a ue transition
piece (supplied) is required to t over the outlet of the
induced draft assembly on the appliance.
NOTE - If needed, loosen the upper right two or three
screws securing the combustion air blower. Slide the tran-
sition into place and secure loosened screws.
3 - Keep the vent connector runs as short as possible
with a minimum number of elbows. Refer to the
current edition of ANSI Z223.1 or CSA-B149
installation compliance codes for maximum vent and
vent connector lengths.
4 - The entire length of a single-wall metal vent connector
shall be readily accessible for inspection, cleaning
and replacement.
5 - Single-wall vent pipe used as vertical vent in
commercial applications must not pass through any
attic, interior wall, concealed space, or oor.
TABLE 3
MAXIMUM HORIZONTAL VENT CONNECTOR AND
HORIZONTAL VENT PIPE LENGTHS
No. of
Elbows
30, 45, 60, 75, 090, 105, 100,
115, 145, 175, 200, 350, 400
250 & 300
ft m ft m
1 25 7.6 35 10.7
2 20 6.1 30 9.1
3 15 4.6 25 7.6
4 10 3.0 20 6.1
5 5 1.5 15 4.6
6 - - 10 3.0
7 - - 5 1.5
VENT TERMINATION ON SINGLE-WALL VERTICAL VENT RUNS
SINGLE-WALL VENT PIPE WITH
SINGLE-WALL TERMINATION
SINGLE-WALL VENT PIPE WITH
DOUBLE-WALL (TYPE B-1) TERMINATION
ROOF FLASHING
ROOF PITCHED
FROM 0” TO 45”
2” CLEARANCE
THIMBLE
CLEARANCE TO BE
AS SPECIFIED ON
TYPE “B” VENT PIPE.
12” MAX
ROOF FLASHING
ROOF PITCHED
FROM 0” TO 45”
SEAL JOINT BETWEEN SINGLE-WALL VENT AND “B” VENT TERMINATION
AND THE OPEN SPACE BETWEEN THE SINGLE WALL VENT PIPE AND
THE OUTER PIPE OF THE “B” VENT TERMINATION.
Commercial Application Only
FIGURE 3
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