Venting
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GKNE-SVX001B-EN
Horizontally Vented Unit Heaters
(Category III)
Horizontal venting arrangements are designed to be used
with single wall vent pipe. Horizontal venting
arrangements must terminate external to the building
using UL 1738 Listed and approved single wall or double
wall vent. For installations in Canada, use corrosion
resistant and gas-tight, listed vent pipe conforming with
local building codes, or in the absence of local building
codes, with current CSA-B149.1, Installation Codes for
Natural Gas Burning Appliances and Equipment or CSA-
B149.2, Installation Codes for Propane Gas Burning
Appliances and Equipment.
Single wall and double wall venting components which
are UL 1738 Listed and approved for Category III positive
pressure venting systems MUST be used.
A Breidert Type L, Fields Starkap, or equivalent vent cap
must be supplied by the customer for each power vented
unit. The vent pipe diameter MUST be as specified in
Table1. All unit sizes are factory equipped with the
required flue size collar; attach in place (if not mounted to
outlet); refer to included vent collar instruction sheet for
additional requirements. The vent terminal must be at
least 12-inch (305mm) from the exterior of the wall that it
passes through to prevent degradation of the building
material by flue gases.
Through the wall vent for these appliances shall NOT
terminate over public walkways, or over an area where the
condensate or vapor could create a nuisance or hazard or
could be detrimental to the operation of regulators, relief
valves, or other equipment.
The vent pipe equivalent length must not exceed 50-
feet(15.2m). Equivalent length is the total length of straight
sections PLUS 10-ft. (3.05m) for each 90° elbow and 4 ft.
(1.22m) for each 45° elbow.
Maintain clearance between the vent pipe and
combustible materials according to vent pipe
manufacturer's instructions
Seal all vent pipe joints and seams to prevent leakage. Use
General Electric RTV-108, Dow-Corning RTV-732 silicone
sealant or equivalent sealant with a temperature rating of
500° F; or 3M #425 aluminum foil tape (or equivalent). The
vent air system must be installed to prevent collection of
condensate. Pitch horizontal pipes downward 1/4-inch per
ft. (21mm per meter) toward the outlet for condensate
drainage.
Horizontal portions of the venting systems shall be
supported at maximum intervals of 4 feet (1.2m) to
prevent sagging (in Canada, support at 3 feet (1m)
maximum intervals).
Insulate single wall vent pipe exposed to cold air or
running through unheated areas.
Each unit must have an individual vent pipe and vent
terminal!
Each unit MUST NOT be connected to other
vent systems or to a chimney.
WARNING
Do not use Type B (double wall) vent internally within
the building on horizontally vented power vented units!
This can result in death, serious injury or substantial
property damage.
Table 8.
Vent systems termination clearance requirements
Vent Systems Termination Clearance Requirements
Structure/Object
Minimum Clearance for Termination Locations
USA
CANADA
Door, window, or gravity vent inlet;
combustion air inlet for other appliances
9 inch for 10,000 to 50,000 BTU/Hr input; 12
inch for input exceeding 50,000 BTU/Hr.
9 inch (230mm) for 10,000 to 50,000 BTU/Hr
input; 12 inch (305mm) for input exceeding
50,000 BTU/Hr.
Forced air inlet within 10 feet
3 feet above
6 feet (1.8m)
Adjoining Building or parapet
6 feet
6 feet (3.04m)
Adjacent public walkways
7 feet above grade
7 feet (2.1m) above grade
Electric, gas meters & regulators
4 feet horizontal
3 feet (0.9m) horizontally from meter/regulator
assembly. 6 feet (1.8m), any direction, from a
gas service regulator vent outlet
Above grade level
(a)
1 foot
1 foot (0.3m)
(a) Above maximum anticipated snow depth.
NOTICE
Combustion and exhaust venting instructions below
describe two-pipe venting. If venting concentrically, a
Combustion Air Inlet Kit is required and instructions
included in the kit should be followed.
