11
"Fireplace" Installation
FIREPLACE INSTALLATION
Connection of the stovepipe directly into the
existing masonry chimney over the fireplace opening
is a more desirable method. This installation performs
better, yielding more heat and better draft; it is also
easy to clean and inspect for creosote. Before
beginning this type of installation plan carefully; a
high degree of skill is required to insure safety.
An entry port for the stovepipe must be cut through
the chimney with minimum damage to the fireclay
liner. Some involved measurements may be required
to locate the flue liner exactly. Before cutting, take
time to mark the size and position of the entry port.
Position the entry port so that at least 8 inches of the
flue liner remains below the port.
Keep in mind that wood mantels and combustible
trim around the fireplace must have adequate
clearances from the heater and stovepipe or must be
protected in an approved manner. Also, be sure to
leave at least an 18 inch clearance between the top
of the stovepipe and the combustible ceiling or other
combustibles. Placing the center of the entry port 2
feet below the ceiling will insure proper clearance for
6-inch, 8-inch, and 10-inch stovepipes. Next, install
a fireclay (at least 5/8 inch thick) or metal thimble,
being sure that the thimble is flush with the inner flue
lining, secure the thimble in place with refractory
mortar. The thimble should be surrounded on all sides
with 8 inches of brickwork (solid masonry units) or 24
inches of stone.
Install the stovepipe as far as possible into the
thimble, but not past the inside of the flue lining.
There should be a small airspace (approximately 1/2
inch) between the stovepipe and thimble, allowing
for expansion of the stovepipe. Seal this airspace
with high-temperature caulking or ceramic wool. Do
not use the Type B installation (not illustrated in this
manual), that is, venting up through the fireplace
opening, regardless of whether the fireplace opening
is closed.
Masonry chimneys have several positive attributes:
If properly built, they are quite durable, and most
homeowners consider them more attractive perhaps
than an unenclosed factory built chimney. And, if
the chimney is located within the confines of the
house (that is, not attached to an exterior wall), its
mass alone will store heat longer and continue to
release the heat long after the fire has died. Masonry
chimneys have many disadvantages though.
Masonry chimneys constructed on an exterior wall are
exposed to cold outdoor temperatures, promoting
greater heat loss, higher accumulations of creosote,
and reduced draft which leads to poorer heater or
furnace performance.
