Sterling GG - Manual (Page 20)

20
VERTICALLY VENTED, CATEGORY III – Figures 13B, 15 & 17
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 single or double
wall pipe listed for positive pressure vent systems.
2. Each unit must have an individual vent pipe and
vent terminal. Unit MUST NOT be connected to
other vent systems or to a chimney.
3. Category III units are limited to a maximum of
40 feet (12.19m) equivalent length of vent pipe.
Equivalent length is the total length of straight
sections PLUS 5 feet (1.5m) for each 90 degree
elbow and 2.5 feet (.75m) for each 45 degree elbow.
4. 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. Slope horizontal runs
upward from the gas unit heater at least 1/4-inch
per foot (21mm/m) minimum. 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). (See Figures 13B, 15
and 17)
5. 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.
STANDARD COMBUSTION
HORIZONTALLY VENTED, CATEGORY III - Figures 13A, 14 & 16
Observe the following precautions when venting the unit:
1. Use flue pipe of the same size as the flue
connection(s) on the gas unit heater, 4 inches
(102mm). All heaters must be vented with a single
or double wall pipe listed for category III positive
pressure vent systems. (UL 1738 listed AL29-4C).
2. Each unit must have an individual vent pipe and
vent terminal. Unit MUST NOT be connected to
other vent systems or to a chimney.
3. Category III units are limited to a maximum of
40 feet (12.19m) equivalent length of vent pipe.
Equivalent length is the total length of straight
sections PLUS 5 feet (1.5m) for each 90 degree
elbow and 2.5 feet (.75m) for each 45 degree elbow.
4. An Amerivent Americap or Metalbestos vent cap
must be supplied by the customer for each power
vented unit. The vent pipe diameter must be 4 inches
(102mm).
5. The vent ter minal must be at least 12 inches
(305mm) from the exterior of the wall that
it passes through to prevent degradation of the
building materials by fl ue gasses.
6. Through the wall venting for these appliances shall
not terminate over public walkways, or over an area
where the condensate or vapor could create a
nuisance, hazard, or could be detrimental to the
operation of regulators, relief valves, or other
equipment. See Figures 13A, 14, 16 and Table 4.
7. Maintain clearance between the vent pipe and
combustible materials according to vent pipe
manufacturer’s instructions.
8. The vent system must be installed to prevent
collection of condensate. Pitch horizontal pipes
downward 1/4 inch per foot (21mm per meter)
toward the outlet for condensate drainage. Install a
tee with a condensate drain at the low point of the
pipe (see Figure 13A). As an alternate, a 3/8 inch
diameter hole may be drilled at the low point of the
pipe for condensate drainage.
9. Horizontal portions of the venting system shall be
supported at minimum intervals of 4 feet (1.2m) to
prevent sagging (in Canada, support at 3 foot (1m)
minimum intervals).
10. 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 feet
(3m). Insulation should be a minimum of 1/2 inch
(12.7mm) thick foil faced.