Never connect a Category I appliance to a chimney that is servicing a solid−fuel appliance. If a fireplace chimney flue is used to vent this appliance, the fireplace opening must be permanently sealed.
A type B or listed chimney lining system that passes through an unused masonry chimney flue is not considered to be exposed to the outdoors.
General Venting Requirements
Vent all SL280DFV furnaces according to these instruc- tions:
1 − Vent diameter recommendations and maximum allow- able piping runs are found in the provided venting tables.
2 − In no case should the vent or vent connector diameter be less than the diameter specified in the provided venting tables.
3 − The minimum vent capacity determined by the sizing tables must be less than the low fire input rating and the maximum vent capacity must be greater than the high fire input rating.
4 − Single appliance vents − If the vertical vent or
5 − Multiple appliance vents − The flow area of the largest section of vertical vent or chimney shall not exceed 7 times the smallest listed appliance categorized vent area, drafthood outlet area or flue collar area unless de- signed according to approved engineering methods.
6 − The entire length of single wall metal vent connector shall be readily accessible for inspection, cleaning, and replacement.
7 − Single appliance venting configurations with zero lat- eral lengths (tables 5 and 6) are assumed to have no elbows in the vent system. For all other vent configura- tions, the vent system is assumed to have two 90° el- bows. For each additional 90° elbow or equivalent (for example two 45° elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10% (0.90 x maximum listed ca- pacity).
8 − The common venting tables (7, 8, 9, and 10) were gen- erated using a maximum horizontal vent connector length of 1−1/2 feet (.46 m) for each inch (25 mm) of connector diameter as follows:
TABLE 4
Connector Diameter | Maximum Horizontal |
inches (mm) | Connector Length feet (m) |
|
|
|
|
3 (76) | 4−1/2 (1.37) |
|
|
4 (102) | 6 (1.83) |
|
|
5 (127) | 7−1/2 (2.29) |
|
|
6 (152) | 9 (2.74) |
|
|
7 (178) | 10−1/2 (3.20) |
9 − If the common vertical vent is offset, the maximum common vent capacity listed in the common venting tables should be reduced by 20%, the equivalent of two 90° elbows (0.80 x maximum common vent capacity). The horizontal length of the offset shall not exceed
10− The vent pipe should be as short as possible with the least number of elbows and angles required to com- plete the job. Route the vent connector to the vent us- ing the shortest possible route.
11− A vent connector shall be supported without any dips or sags and shall slope a minimum of 1/4 inch (6.4 mm) per linear foot (305 mm) of connector, back toward the appliance.
12− Vent connectors shall be firmly attached to the furnace flue collar by self−drilling 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 screws or other approved means.
13− 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
14− 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 lo- cal codes. In absence of local codes, refer to NFGC (Z223.1).
15− No portion of the venting system can extend into, or pass through any circulation air duct or plenum.
16− 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.
17− 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%, the equivalent of one 90° elbow (0.90 x maximum common vent capacity).
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