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given; this is known as the horizontal vent connector run. The vent or chimney height is also
usually given as the Btuh input of the gas appliances served by the vent.
Check these parameters to be sure the venting system will work. Use approved engineering
practices and part 7 & 10 of the latest revision of the (NFGC) National Fuel Gas Code,
ANSI Z223.1/NFPA54. When installed in Canada: The latest revision of the CAN/CSA - B149
Natural Gas and Propane Installation Code.
2. Use this venting addendum for single appliance venting and multiple appliance (common)
venting. For multistory installations, refer to the latest revision of the National Fuel Gas Code
ANSI Z223.1/NFPA 54. When installed in Canada: The latest revision of the CAN/CSA - B149
Natural Gas and Propane Installation Code.
D. VENT CONNECTOR
1. Vent connectors must be made of noncombustible, corrosion resistant material
capable of withstanding vent gas temperatures. They must be thick enough to withstand
physical damage and be accessible for inspection, cleaning and replacement.
2. Use Type B 1 vent connector in or through attics, crawl spaces, or other cold areas.
Install thimbles that meet local codes when vent connectors pass through walls or partitions
of combustible material.
3. Keep vent connectors as short as possible by locating boiler as close as practical to
vent or chimney. Avoid unnecessary turns or bends which create resistance to flow of vent
gases. Adding an elbow adds resistance. For example, adding a 6" 90-degree elbow would
be the equivalent of adding 20 feet of horizontal 6" pipe. (45-degree elbows have lower
resistance than 90-degree elbows, and can work for most vent runs).
4. If you join two or more vent connectors before they enter the vertical vent or chimney,
see figure17,on page17. Also refer to NFGC book, ANSI standards and NFPA book. In
Canada refer to the CAN/CSA - B149 Natural Gas and Propane Installation Code.
5. Do not connect this boiler to any portion of a vent system which operates under positive
pressure. Positive pressure will result with CATEGORY 3 or 4 appliances that are connected
to the vent.
6. Do not connect vent connector to a chimney flue serving a fireplace.
E. VERTICAL VENT OR CHIMNEY
1. Vents and chimneys usually extend vertically with offsets not exceeding 45-degrees.
Consider vent pipe runs more than 45-degrees as horizontal runs. Include their length in the
total horizontal run.
2. Designer and installer must provide an appropriately sized common vent for all
appliances connected to it (Ref. to figure 17, on page 17 or the latest revision of the NFGC,
ANSI Z223.1. When installed in Canada: The latest revision of the CAN/CSA - B149 Natural
Gas and Propane Installtion Code).
3. Connect this CATEGORY 1 boiler only to vent systems with other CATEGORY 1
appliances.