STANDARD COMBUSTION
VERTICALLY VENTED, CATEGORY I - Figure 12
Observe the following precautions when venting the unit:
1.Use flue pipe of the same size as the fl ue connection(s) on the gas unit heater 4" (102mm). All heaters must be vented with a UL Listed, Type B or single wall vent, a factory built chimney, or a lined brick and mortar chimney that has been constructed in accordance with the National Building Code. All tables and dimensions assume B vent for the flue and single wall pipe or B vent for the connector.
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.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.
4.Slope horizontal runs upward from the gas unit heater at least
G a s C o d e , A N S I Z 2 2 3 . 1 . Horizontal portions of the venting system shall be suppor ted at minimum intervals
of 4 feet (1 . 2m) (in Canada, suppor t at 3 foot intervals (1m) minimum intervals.
5.Use as few elbows as possible.
6.Seal all vent pipe joints
and seams to prevent leakage. Use General Electric
or 3M #425 aluminum foil tape (or equivalent).
7.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" (12.7 mm) thick foil faced.
Figure 12
HORIZONTALLY VENTED, CATEGORY I - Figure 13
Observe the following precautions when venting the unit:
1.Use fl ue pipe of the size shown on Table 5. All heaters must be vented with a UL Listed, Type B or single wall vent. Refer to Table 5 for dimensional restrictions.
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.A minimum ver tical rise is required for Category I venting. See Table 5 for specifications. The vent terminal must be at least 3 feet (1m) above grade, or in snow areas, at least 3 feet (1m) above the snow line to prevent blockage by snow. Install a weather cap over the vent opening. An Amerivent
A m e r i c a p o r M e t a l b e s t o s vent cap must be supplied by the customer for each power vented unit.
4.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.
5.Seal all vent pipe joints and seams to prevent leakage. Use General Electric
# 425 aluminum foil tape (or equivalent). 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 13). As an alternate, a 3/8 inch diameter hole may be drilled at the low point of the pipe for condensate drainage.
6.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).
8.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.
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