Installation Guide

PG 3
CLEARANCES
Always allow at least a 2-inch clearance between Model AF-HST chimney pipe and any
combustible materials. Never fill any required clearance space with insulation or any
other materials. Combustible materials include lumber, plywood, sheetrock, plaster and
lath, furniture, curtains, electrical wiring and building insulation. Keep single wall
stovepipe at least 18 inches away from combustible materials, unless a clearance
reduction system that is acceptable to the authority having jurisdiction is used, or the
appliance to be installed is listed and the instructions specify a different clearance.
PERMITS
Contact your local Building Official or Fire Official regarding permits, restrictions, and
installation inspections in your area.
MODEL AF-HST APPLICATION
Model AF-HST chimney is UL 103 Type HT double wall insulated chimney, which can
be used with wood stoves, fireplaces, fireboxes, furnaces, boilers, water heaters,
stoves, ranges, or other residential-type appliances fueled by oil, gas, coal, or wood,
that require a chimney system. Do NOT use model AF-HST chimney with forced draft,
positive-pressure appliances.
CHIMNEY DIAMETER
Follow the appliance manufacturer’s instructions to determine chimney diameter and
clearances between combustible materials and your heating appliance. Never choose a
chimney with an inside diameter smaller than your appliance’s outlet. To calculate the
chimney’s outside diameter, add 2 inches to the inside diameter.
CHIMNEY HEIGHT
The National Fire Protection Association Standard #211 states: “Chimneys shall extend
at least three feet above the highest point where it passes through the roof of a building,
and at least two feet higher than any portion of a building within ten feet.” (Fig 1). If the
chimney extends more than 5 feet above the roof, a Roof Brace must be used (see
page 11). Due to the overlap of joints, subtract 1-⅛ inches from each Chimney
Section’s height to calculate installed height.
The chimney shall be at least 10 feet away from adjacent walls or buildings.
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