Sterling TD - Manual (Page 18)

18
VENTING (continued)
HORIZONTALLY VENTED DUCT FURNACES (CATEGORY III)
Observe the following precautions when venting the unit:
1. Horizontal venting arrangements are designed to be
used with single wall or double wall vent pipe.
Horizontal venting arrangements must terminate
external to the building using UL 1738 vent pipe in
the United States. For installations in Canada, use
vent pipe conforming with UL S636, local building
codes, or in the absence of local building codes, with
current CSA-B149.1 Installation Codes for Natural
Gas Bur ning Appliances and Equipment, or
CSA-B149.2 Installation Codes for Propane Gas
Burning Appliances and Equipment.
Do not use Type B (double wall)
vent internally within the building on power
vented units that are vented horizontally.
2. Single wall and double wall venting components
which are UL Listed and approved for Category III
positive pressure venting systems MUST be used.
3. A Breidert Type L or Fields Starkap vent cap must be
supplied by the customer for each power vented unit.
The vent pipe diameter MUST be as specifi ed in Table
1 (“F” Flue Size Diameter). All unit sizes are factory
equipped with the required fl ue size collar.
4. The vent terminal must be at least 12 inches (305mm)
from the exterior of the wall that it passes through
to prevent degradation of the building material by
fl ue gases. Minimum and maximum wall thickness
for the venting system consist of 4-1/4 inch (105mm)
to 8-1/2 inch (216mm) for 5 inch (127mm) diameter
vent pipe and 5-3/4 inch (146mm) to 11-1/2 inches
(292mm) on 6 inch (152mm) vent pipe.
5. 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. See Figure 8B and Table 6 for vent
terminal height and snow consideration requirements.
6. The vent pipe equivalent length must not exceed
50 feet (15.2m). Equivalent length is the total length
of straight sections PLUS 10 feet (3.05m) for each
90 degree elbow and 4 feet (1.22m) for each 45
degree elbow.
7. Maintain clearance between the vent pipe and
combustible materials in accordance with the vent
pipe manufacturer’s instructions.
8. The vent system must be installed to prevent
collection of condensate. Pitch horizontal portions of
vent pipe downward 1/4 inch per foot (21mm/m)
toward the outlet for condensate drainage. See Figure
8B.
9. Horizontal portions of the venting system shall be
supported at maximum intervals of 4 feet (1.2m) in
the United States, and at minimum intervals of 3 feet
(1m) in Canada.
10. Insulate single wall vent pipes exposed to cold air or
running through unheated areas.
11. 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.