10
"fIREPLACE" INSTALLATION (CONT'D)
fIREPLACE INSTALLATION
Connection of the stovepipe directly into the
existing masonry chimney over the fireplace
opening is a more desirable method. This instal-
lation performs better, yielding more heat and
better draft; it is also easy to clean and inspect
for creosote. Before beginning this type of in-
stallation 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 com-
bustible 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. Finally, be sure to wire the damper
closed and apply the same sealant you used at
the stovepipe and thimble junction.
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 attri-
butes: If properly built, they are quite durable,
and most homeowners consider them more at-
tractive 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.