6
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5. Do not insulate on top of the firebox. The opening in the
collar around the chimney at the top of the fireplace must not
be obstructed (see figure 11).
6. Before finishing the fireplace enclosure, inspect all joints of
the outer firebox. Seal any gaps of the outer firebox with a
non-combustible material. Caulk any gaps between the
nailing flange and framing.
CHIMNEY SYSTEM:
CHIMNEY HEIGHT
Minimum chimney height measured from bottom of fireplace
to flue gas outlet-end of the termination is:
Straight
run
16
feet
Run with one elbow set
16 feet
Run with two elbow sets
30 feet
An elbow set is consist of one starter elbow and one return
elbow. Uncommon circumstances such as neighboring hills,
tall trees, or strong wind areas can cause downdrafts in the
chimney system. In such cases, going beyond the minimum
recommended height would be preferable to provide a better
draw.
Maximum height approved for any chimney run with this
fireplace system is 60 feet as measured from the bottom of the
fireplace to the flue outlet-end of the termination.
ASSEMBLING AND INSTALLING THE DOUBLE WALL
CHIMNEY SYSTEM
The DESA chimney system consists of 12, 18, 24, 36 and 48-
inch, snap-lock double-wall pipe segments, planned for
maximum adaptability to individual site requirements. Actual
lengths gained (lineal gain) after fitting overlaps must be taken
into consideration (see figure 12).
Each double wall chimney section consists of a galvanized
outer pipe, a stainless steel inner flue pipe and a wire spacer.
The pipe sections must be assembled independently as the
chimney is installed. When attaching the chimney directly to
the fireplace, the inner flue pipe section must be installed first
with the female side up (see figure 12). The outer pipe section
can then be installed over the flue pipe section with the male
end up.
Press down on each pipe section until the lances securely
engage the hem on the fireplace starter. The wire will assure
the proper spacing between the inner and outer pipe sections
(see figure 12).
Continue to assemble chimney sections as outlined above,
making sure that both the inner and outer pipe sections are
locked together.
When installing double wall “snap-lock” chimney together, it
is important to insure that the joint between the chimney
sections is locked. Check by pulling chimney upward after
locking. The chimney will not come apart if properly locked.
It is not necessary to add screws to keep the chimney together.
However, if desired, use screws per directions provided on
page 7, figure 14.
Figure 10 COLD CLIMATE INSTALLATION
Figure 11 FIREPLACE COLLAR OPENING
Figure 12 LINEAL GAIN
