Sterling GG User Manual
Page 18
18
STANDARD COMBUSTION
VERTICALLY VENTED, CATEGORY I - Figure 12
Observe the following precautions when venting the unit:
1. Use
fl ue pipe of the same size as the fl ue connection(s)
on the gas unit heater 4 inches (102mm). All heaters
must be vented with a UL 1738 listed, double or single
wall vent, Type B vent, a factory built chimney, or a
lined brick and mor tar chimney that has been
constructed in accordance with the National Building
Code. All tables and dimensions assume double wall
for the fl ue and single wall pipe or double wall for the
connector.
2. A minimum vertical rise of 5 feet (1.5m) is required
for Category I venting. The top of the vent pipe
should extend at least 2 feet (0.61m) above the
highest point on the roof. Consideration should be
made for anticipated snow depth. Install an
Amerivent Americap or Metalbestos vent cap over
the vent opening.
3. Slope horizontal runs upward from the gas unit heater
at least 1/4-inch per foot (21mm/m) minimum.
Horizontal Vent Connector length should not exceed
75% of the vertical height of the vent pipe. Maximum
vent connector length is 10 feet (3m). For exceptions
see Ch. 10 of the National Fuel Gas Code, ANSI
Z223.1 (NFPA 54). Horizontal portions of the venting
system shall be supported at minimum intervals of
4 feet (1.2m) (in Canada, support at 3 foot (1m)
minimum intervals). Maintain clearance between the
vent pipe and combustible materials per vent pipe
manufacturer’s instructions.
4. Use as few elbows as possible.
5. Seal all vent pipe joints and seams to prevent
leakage. Use General Electric RTV-108, Dow-
Corning RTV-732, or equivalent silicone sealant with
a temperature rating of 500°F, or 3M #425 aluminum
foil tape (or equivalent). See Figure 12A.
6. Avoid running vent pipe through unheated spaces.
When this cannot be avoided, insulate the pipe to
prevent condensation of moisture on the walls of the
pipe. Insulate vent pipe runs longer than 10 ft (3m).
Insulation should be a minimum of 1/2 inch (12.7 mm)
thick foil faced.