15
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
WARNING
•
Air shutter adjustment should
only be performed by a quali-
fied professional service
technician.
•
Ensure front glass panel are
in place and sealed during
adjustment.
CAUTION
• Soot will be produced if the
air shutter is closed too much.
Any damage due to carboning
resulting from improperly
setting the air shutter is not
covered under the warranty.
•
The air shutter door and nearby
appliance surfaces are hot.
Exercise caution to avoid
injury while adjusting flame
appearance.
Burner Air Shutter Adjustment Procedure
LENNOX HEARTH PRODUCTS • MERIT
®
SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • CARE AND OPERATION
Electronic Appliance Checkout
To light the burner, refer to the lighting instruc-
tions on
Page 22
. Ensure the igniter lights the
pilot. The pilot flame should engulf the flame
sensor as shown in
Figure 10.
Millivolt Appliance Checkout
The pilot flame should be steady, not lifting
or floating. Flame should be blue in color with
traces of orange at the outer edge.
The top 3/8" (10 mm) at the pilot generator
(thermopile) and the top 1/8" minimum (tip)
of the quick drop out thermocouple should be
engulfed in the pilot flame. The flame should
project 1" (25 mm) beyond the hood at all three
ports (see
Figure 9
)
.
To light the burner, refer to the lighting instruc-
tions on
Page 20.
1
. Locate adjustment rod and adjust air shutter
to the standard setting as shown in
Figure
8
(adjustment rod is located in the lower
control compartment).
NOTE:
Rotating the adjustment rod down
to decrease air and up to increase air.
2.
Light appliance (follow lighting procedure on
lighting label in control compartment or see
the lighting instructions,
Pages 20 - 23
in
this manual).
3.
Allow the burner to operate for at least 15 min-
utes while observing the flame continuously
to ensure that the proper flame appearance
has been achieved (
Figure 7
). If the following
conditions are present, adjust accordingly.
• If flame appears weak or sooty, adjust the
air shutter, incrementally, to a more open
position until the proper flame appearance
is achieved.
• If flame stays lowered blue, adjust the air
shutter, incrementally, to a more closed
position until the proper flame appearance
is achieved.
4. Leave the control knob (off/pilot/on) in the
ON position (millivolt models) and the burner
OFF/ON switch OFF (and remote switches,
if applicable).
5.
When satisfied that the burner flame ap-
pearance is normal, close the lower control
compartment door (
Figure 7
on
Page 14
).
Thermocouple
Thermopile
Pilot
Nozzels
3/8" Min.
(9 mm)
Igniter Rod
Pilot Hood
Figure 9 - Millivolt Pilot
Figure 10 - Electronic Pilot
Pilot
Hood
Flame Rod
(Sensor)
Igniter
Figure 8 - Burner Air Shutter
Adjustment
Air Shutter
Burner
Tube
Adjustment Set-Screw
Adjustment Rod Down
(fully open air opening
position)
Main Burner Factory Air Shutter
Opening Setting
Model
Natural
Gas
Propane
Gas
MLDVTCD-35
Closed
Expose half of
the hole
Adjustment
Rod Up
(closed min.
position)
