Venting
NOTE
− The vent is a passageway, vertical or nearly
so, used to convey flue gases from an appliance, or its
vent connector, to the outside atmosphere. The vent
connector is the pipe or duct that connects a fuel-gas
burning appliance to a vent or chimney.
NOTE
− Local codes may supersede any of these
provisions.
GENERAL RECOMMENDATION AND
REQUIREMENTS
HED duct heaters must be vented in compliance with the
latest edition of the National Fuel Gas Code (NFPA 54 /
ANSI Z223.1) in the USA and with CSA−B149.1 codes in
Canada, as well as applicable provisions of local
building codes, and the following instructions.
A sheet metal flue transition is supplied with this
certified unit. It must not be modified or altered and
must be installed on the outlet of the combustion
air inducer assembly prior to the installation of the
vent connector. Failure to comply with this
requirement will void the certification of the unit by
the approval agencies.
A single-wall vent connector may be used in all
applications between the furnace and the vertical vent
pipe.
UL−approved Category III venting materials must
be used in all horizontal vent piping applications.
A single−wall vent pipe used as a vent connector or as a
vertical vent 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 must not pass through any attic, interior
wall, concealed space, or floor.
VERTICAL VENTS USING METAL VENT PIPE
All HED duct heaters are listed as Category 1
appliances for vertical vent installations.
1 − All HED duct heaters are to be used with NFPA− or
ANSI− approved chimneys or U.L.−listed type B−1
gas vents where applicable, as well as the
modifications and limitations listed in figure 2. Seal
single−wall vent material according to
General
Recommendations and Requirements
section.
2 − 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. Horizontal run of the
vent connector from the combustion air inducer
outlet to the chimney/vent pipe cannot exceed the
values in table 3.
A single 3" (76 mm), 4" (102mm), or 5" (127 mm)
elbow is equivalent to 5 feet (1.53 m) of vent pipe.
A single 6" (152mm) elbow is equivalent to 9 feet
(2.75 m) of vent pipe.
Single−wall vent connector shall not be insulated.
TABLE 2
VENT CONNECTOR DIAMETERS
Model Number
Connector Diameter
HED−100
HED−115
4" (102mm)
HED−145
HED−175
HED−200
HED−230
5" (127mm)
HED−250
HED−300
3 − All HED models may be vented vertically as a single
appliance, or as a common vent with other gas−fired
appliances. In a common venting situation, vent
connectors for other appliances must be joined to
the vent at least 4" (102 mm) above the connected
HED connection. When common venting with
another HED unit, maintain at least a 4" (102 mm)
vertical separation between the vent connectors.
4 − Clearance to combustible material is 6" (152mm)
for single−wall vent material except where a listed
clearance thimble is used. Clearance to
combustible material for type B-1 vent or
factory−built chimney is per manufacturer’s
instructions.
5 − The vent connector must be supported with hangers
no more than three feet (1m) apart to prevent
movement after installation. All horizontal vent
connector runs must have a slope up to the vertical
vent of at least 1/4" per foot (1mm per 50mm).
6 − All vertical vents must be terminated with a listed
vent cap or rain shield assembly unless local
codes permit otherwise.
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