Lennox Hearth T300HT manual Chimney Inspection, Chimney Height Requirements, Draft Requirements

INSTALLATION

CHIMNEY INSPECTION

Existing chimneys must be inspected before installing your stove. Consult your local building department for chimney code requirements. A masonry chimney must have a code approved liner. This liner must not have broken or missing pieces. Some non-code masonry chimneys may be brought up to code by being relined. (Consult your dealer or qualified chimney sweep). Fac- tory built chimneys should also be inspected, first for creosote deposits (which should be removed), and then for integrity of the stainless steel liner. Look for obvious bulges in the lining, which may indicate the need to re- place that section (use a bright flashlight). Also, inspect the attic to see that the chimney has proper clearance to combustible framing members. For interior masonry chimneys and most factory built chimneys, this must be a (2) two-inch air space clearance, which must not be filled with insulation or any other material. An exterior masonry chimney must have a (1) one-inch air space clearance.

CHIMNEY HEIGHT REQUIREMENTS

The chimney must extend 3 feet above the level of roof penetration and a minimum of 2 feet higher than any roof surface within 10 feet (see below). Check with your local building officials for any additional requirements for your area.

Due to prevailing winds, local terrain, adjacent tall trees, a hill, or ravine near the home, or adjacent structures, additional chimney height or a special chimney cap may be required to ensure optimum performance.

DRAFT REQUIREMENTS

The appliance is merely one component of a larger system. The other equally important component is the venting system. This is necessary for achieving the re- quired flow of combustion air to the fire chamber and for safely removing unwanted combustion byproducts from the appliance. If the venting system's design does not promote these ends, the system may not function prop- erly. Poorly functioning venting systems may create performance problems as well as be a safety hazard (i.e. an oversized chimney may result in less than opti- mum performance. Installations into a large, masonry chimney may require a liner to improve performance). A draft test should read greater than .04' W.C. (inches water column) and less than .08" W.C.

American National Standards Institute ANSI/NFPA 211- 92, draft 1-7: A chimney or vent shall be so designed and constructed to develop a flow sufficient to com- pletely remove all flue and vent gases to the outside atmosphere. The venting system shall satisfy the draft requirements of the connected appliance in accordance with the manufacturer instructions.

Requires a listed termi- nation cap

Top of the flue must be 2’ (610 mm) higher than any part of roof within 10’ (305 cm) horizontal

Top of the flue must be 3’ (915

mm)higher than highest point of roof penetration

These rules are minimums. In some instances, chimney height may need to be increased to achieve sufficient draft.

To achieve a stable draft, the total flue height required (from the appliance to termination) is 12 to 15 feet minimum.

PAGE 8