4
Figure 4
B. Solid insulated, listed factory-built chim ney
length of the sam e inside diam eter as the
chim ney connector and having 1 inch or more
of insulation w ith a minimum 9 inches air
space betw een the outer w all of the chim ney
length and com bustibles.
C. Sheet steel chim ney connector, minim um 24
gauge in thickness with a ventilated thim ble,
m inim um 24 gauge in thickness, having tw o 1
inch air channels, separated from
combustibles by a minim um of 6 inches of
glass fiber insulation. Opening shall be
covered, and thim ble support with a sheet
steel support, minim um 24 gauge in thickness.
D. Solid insulated, listed, factory-built chim ney
length, w ith an inside diam eter 2 inch larger
than the chim ney connector, and having 1 inch
or more of insulation. Serving as a
pass-through for a single w all sheet steel
chim ney connector of minim um 24 gauge
thickness, w ith a m inim um 2 inch air space
betw een the outer w all of the chim ney section
and com bustibles. M inim um length of a
chim ney section shall be 12 inches chim ney
section spaced 1inch aw ay from connector
using sheet steel support plates on both ends
of chim ney section. Opening shall be covered,
an chim ney section supported on both sides
w ith sheet steel support securely fastened to
w all surface of m inimum 24 gauge thickness.
Fasteners used to secure chim ney section
shall not penetrate chim ney flue liner.
E.
Proper Draft
The chimney draft greatly influences the operation.
Too little draft can cause sm oke to puff from the
therm ostat dam per or from the door. To increase
draft: use a larger flue pipe, shorten connector
pipe or extend chim ney height. Too much draft
could cause overheating. A barom etric dam per
installed in the connector pipe close to the heater
can control excessive draft.
The flue area of the chim ney should be a minim um
area equivalent to 6" diam eter flue pipe.
If necessary, the draft can be checked by qualified
serviceman and should have a draft of .04 inches
of w ater colum n m inim um and .07 m axim um .
Chim ney Draft
1.
Factory Build Chim neys
: M ust be listed type
HT per UL 103. NFPA No.211 requires factory built
chim neys to be listed and installed in accordance
w ith conditions of the listing and the
m anufacturer’s instructions. NFPA No.211 also
requires the chim ney to extend at least 3 feet
above the highest point w here it passes through
the roof, and at least 2 feet higher than any portion
of a building w ithin 10 feet of the pipe. (See
figures 2 & 3)
2.
Brick Chimney with Thimble
: W hen an existing
chim ney is used be sure it is in good repair and
has a suitable chim ney flue liner.
A solid fuel heater should not be connected to the
same chimney as other heating appliances.
Unsatisfactory perform ance can result from
variable or insufficient draft.
A connector to masonry chim ney shall extend
through the inner face or liner but not beyond, and
shall be firm ly cem ented to masonry chimney. A
thim ble may be used to facilitate rem oval of the
chim ney connector for cleaning, in which case the
thim ble shall be perm anently cemented in place
w ith high tem perature cem ent (see figure 4).
