Common Venting Using Tile Lined Interior Masonry Chimney and Combined Vent Connector
NOTE: Refer to provided venting tables for installations.
NOTE: The chimney must be properly sized per provided venting tables or lined with listed metal lining system.
Figure 25
DO NOT insulate the space between the liner and the chimney wall with puffed mica or any other loose granular insulating material.
IMPORTANT
SINGLE appliance venting of a fan assisted furnace into a tile lined masonry chimney (interior or outside wall) is prohibited. The chimney must first be lined with either type B1 vent or an insulated single wall flexible vent lining system which has been sized according to the provided venting tables and the vent pipe manufacturer’s instructions.
A fan assisted furnace may be commonly vented into an existing lined masonry chimney if the following conditions are met:
•The chimney is currently serving at least one drafthood equipped appliance.
•The vent connectors and chimney are sized according to the provided venting tables.
If type B1 double wall vent is used inside a chimney, no other appliance can be vented into the chimney. The outer wall of type B1 vent pipe must not be exposed to flue products. A type B1 vent or masonry chimney liner shall terminate above the roof surface with a listed cap or a’iisted roof assembly according to the terms of their respective listings and the vent manufacturer’s instructions.
When inspection reveals that an existing chimney is not safe for the intended purpose, it shall be rebuilt to conform to nationally recognized standards, lined or relined with suitable materials, or replaced with a gas vent or chimney suitable for venting. The chimney passageway must be checked periodically to ensure that it is clear and free of obstructions.
Do not install a manual damper, barometric draft regulator, or flue restrictor between the furnace and the chimney.
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 furnaces according to these instructions:
1.Vent diameter recommendations and maximum allowable 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 tile lined chimney has a larger diameter or flow area than the vent connector, use the vertical vent diameter to determine the minimum vent capacity and the vent connector diameter to determine the maximum vent capacity. The flow area of the vertical vent, however, shall not exceed 7 times the flow area of the listed appliance categorized vent area, drafthood outlet area or flue collar area unless designed according to approved engineering methods.
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 designed according to approved engineering methods.
Page 16 of 39 | Issue 1031 |