10− A vent connector shall be supported without any dips or sags and shall slope a minimum of 1/4inch (6.4 mm) per linear foot (305 mm) of connector, back toward the appliance. See local and national installation codes for support intervals and methods. National installation code in the U.S.A is current edition of National fuel Gas Code (ANSI−Z223.1/NFPA54). National installation codes in Canada are current editions of CSA−B149 codes.
11− Vent connectors shall be firmly attached to furnace flue collars by sheet metal screws or other approved means, except vent connectors of listed Type B vent material which shall be assembled according to the manufacturer’s instructions. Joints between sections of single wall connector piping shall be fastened by sheet metal screws or other approved means.
12− When the vent connector used for Category I ap- pliances must be located in or pass through a crawl space or other areas which may be cold, that portion of the vent connector shall be constructed of listed double−wall Type B vent material or material having equivalent insulation qualities.
13− All venting pipe passing through floors, walls, and ceil- ings must be installed with the listed clearance to com- bustible materials and be fire stopped according to local codes. In absence of local codes, refer to NFGC (Z223.1/NFPA54).
14− No portion of the venting system can extend into, or pass through any circulation air duct or plenum.
15− Vent connectors serving Category I appliances shall not be connected to any portion of mechanical draft systems operating under positive pressure such as Category III or IV venting systems.
16− If vent connectors are combined prior to entering the common vent, the maximum common vent capacity listed in the common venting tables must be reduced by 10 percent, the equivalent of one 90_ elbow (0.90 x maximum common vent capacity).
17− The common vent diameter must always be at least as large as the largest vent connector diameter.
18− In no case, shall the vent connector be sized more than two consecutive table size diameters over the size of the flue collar outlet.
19− Do not install a manual damper, barometric draft regu- lator or flue restrictor between the furnace and the chimney.
20− When connecting this appliance to an existing dedicated or common venting system, the venting system must be inspected for signs of corrosion and general condition. The sizing of the vent system must be reviewed and must conform to these instructions and the provided venting tables for the USA, and the appropriate venting tables in the standards of CSA B149.1 of the Natural Gas and Propane Installation Code for Canada. If the ex- isting system is in conflict with these requirements, the venting system must be resized.
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