Lennox Hearth ELITE VINT-DVS-U - Manual (Page 15)

15
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
A
Flue Opening in the
top of the firebox
A
Restrictor
Restrictor
Installed Over
Flue Opening
Figure 23
Figure 25
Figure 24
Flue Restrictors
The flue restrictor settings shown in Figures 26 and 27 are for typical
installations and may need to be adjusted from standard to take into
account other variables in the installation to achieve proper combustion.
See Flue Restrictor Guidelines on this page to assist you in making a
proper flue restrictor adjustment.
This appliance uses balanced flue technology to ensure proper combus­
tion. A flue restrictor may need to be installed depending on the vent
configuration of your stove. The drawings on Page 16 show all the al­
lowable pipe configurations for this appliance. To properly install the flue
restrictor, find your pipe configuration in the drawings on Page 16 and
note which restrictor setting is recommended. The flue restrictor and two
black self­tapping 5/32” allen head screws can be found in the firebox
in a plastic bag. The restrictor should be placed over the flue opening
on the ceiling of the firebox. On the restrictor, two self­tapping 5/32”
allen head screws should be installed in either holes 1, 2, 3, or 4 in the
restrictor and screwed into the two holes in the firebox ceiling. See the
drawing to the right for the location of hole numbers on the restrictor. The
numbered holes in which the screws are inserted in the restrictor should
correspond to the restrictor position numbers found on the drawings for
your pipe configuration. Restrictor positions are based on tests run in
a laboratory. The optimum restrictor positions may need to be adjusted
slightly depending on the conditions surrounding the residential instal­
lation. Do not adjust restrictors to a point where the fireplace is sooting.
Notes: The higher the number of the flue restrictor position, the greater
amount of combustion air will be delivered.
Flue Restrictor Adjustment Guidelines
After the flue restrictors have been set to the standard settings as shown
in Figures 26 and 27 on Page 16, the burner flame appearance should be
evaluated to determined if the flue restrictors need to be set to a different
position to adjust for variables in your installation. Light the appliance
and allow it to burn for 20 minutes. See Flame Color and Behavior on
Page 21 to determine if you have a proper burner flame appearance. If
the proper flame appearance cannot be achieved, the flue restrictor may
need to be set to a different position. See the following guidelines to
determine if you need to readjust the flue restrictors.
Before proceeding, confirm the manifold and inlet gas pressure is correct,
primary air shutter is properly adjusted, venting system connections are
secure and not blocked and if you are at a high elevation, ensure unit has
been properly derated:
Symptoms - Lack of Combustion Air
If the symptoms listed below are present, you may need to adjust the
flue restrictor to a more open position.
• Flame appears yellow
• Floating Flames (lazy, ill defined, quiet, may roll)
• Sooting
• Pilot becomes yellow and appliance shuts down
Symptoms - Excessive Combustion Air
If the symptoms listed below are present, you may need to adjust the
flue restrictor to a more closed position.
• Low Flame
• Pilot pulls and appliance shuts down
• Pilot flame ghosts
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