17
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT PLUS
®
DIRECT VENT GAS FIREPLACES (MPDP35/40) • CARE AND OPERATION INSTRUCTIONS
WARNING
•
Air shutter adjustment should
only be performed by a
qualified professional ser-
vice technician.
•
Ensure front glass panel is
in place and sealed during
adjustment.
CAUTION
•
Soot will be produced if
the air shutter is closed too
much. Any damage due
to sooting, 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.
1
. Refer to
Figures 13, and 14
for proper flame
appearance. To adjust the flame, rotate the
adjustment rod toward the back or toward
the front of the fireplace (rod located in the
lower control area). Position the air shutter
to the factory setting as shown in the table
in
Figure 15
.
2.
Light the appliance (follow lighting procedure
on lighting label in control compartment or
in this Care and Operation Instructions).
3.
Allow the burner to operate for at least 15
minutes while observing the flame continu-
ously to ensure that the proper flame ap-
pearance has been achieved. 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 remains blue, adjust the air
shutter, incrementally, to a more closed
position until the proper flame appear-
ance is achieved.
4.
Reinstall the lower control compartment
door.
Figure 15
Electronic Appliance Checkout
To light the burner, turn on the remote control.
Ensure the igniter lights the pilot. The pilot
flame should engulf the flame rod as shown
in
Figure 16
.
BURNER FLAME ADjUSTMENTS
(QUALIFIED TECHNICIANS ONLY)
Pilot
Hood
Sensor
Ignitor
Igniter
Flame Rod
(sensor)
Pilot Hood
s
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e
d
o
M
s
a
G
e
p
y
T
R
I
A
Y
R
O
T
C
A
F
R
E
T
T
U
H
S
G
N
I
T
T
E
S
)
m
m
(
s
e
h
c
n
i
MPDP35
Nat.
1/16 (1.6)
.
p
o
r
P
6
1
/
3
)
6
7
.
4
(
.t
a
N
8
/
1
)
2
.
3
(
.
p
o
r
P
MPDP40
3/8 (9.6)
Adjustment Rod Up
(Fully Open Position)
Air Shutter
Burner Tube
Adjusting Set Screw
Adjustment Rod Down
(minimum air
opening position)
Adjustment Rod Down
(fully open position)
Adjustment Rod Up
(minimum air
opening position)
Figure 16 - Pilot Flame Appearance
