Burner Flame Appearance/Sooting - Lennox Merit Plus MPD35ST-NM-B Care And Operation Instructions Manual

BURNER ADjUSTMENTS
(QUALIFIED TECHNICIANS ONLY)
Flame Appearance and Sooting
Proper flame appearance is a flame which is
blue at the base and becomes yellowish-orange
in the body of the flame.
When the appliance is first lit, the entire flame
may be blue and will gradually turn yellowish-
orange during the first 15 minutes of operation.
If the flame remains blue, or if the flame is
orange with evidence of sooting (black tip), the
air shutter opening may need to be adjusted.
If the air shutter opening is closed too far,
sooting may develop. Sooting is indicated by
black puffs developing at the tips of very long
orange flames. Sooting results in black deposits
forming on the logs, appliance inside surfaces
and on exterior surfaces adjacent to the vent
termination.
Sooting is caused by incomplete combustion
in the flames and lack of combustion air enter-
ing the air shutter opening. To achieve a warm
yellowish-orange flame with an orange body
that does not soot, the shutter opening must be
adjusted between these two extremes.
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Air Shutter Adjustment Guidelines
• If there is smoke or soot present, first
check the log set positioning to ensure that
the flames are not impinging on any of the
logs. If the log set is properly positioned
and a sooting condition still exists, then the
air shutter opening should be increased.
• The more offsets in the vent system, the larger
the air shutter opening will need to be.
• An appliance operated with the air shutter
opened too far, may have flames that appear
blue and transparent. These weak, blue and
transparent flames are termed anemic.
• Propane models may exhibit flames which
candle or appear stringy. If this is present
and persists, adjust the air shutter to a more
closed position, then operate the appliance
for a few more minutes to ensure that the
flame normalizes and the flames do not
appear sooty.
Figure 13 -
Burner Flame Appearance
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
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The following chart is provided to aid you in
achieving the correct air shutter adjustment
for your installation.
Vermiculite
Air Shutter Adjustment Guidelines
Amount of Flame Air Shutter
Primary Air Color Adjustment
If air shutter is Flame will Air shutter
closed too far be orange gap should be
increased
If air shutter is Flame will Air shutter
open too far be blue gap should be
decreased
:
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