Step 10. Burner Adjustments; Step 11. Hood Installation; Finishing Requirements - Lennox Hearth Products Direct Vent MPD-33 Series Installation Instructions Manual

Direct vent mpd-33/35/40/45 series vented gas fireplace heaters
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WARNING: HANDLE THIS GLASS WITH
EXTREME CARE! THE GLASS PANEL IS
SUSCEPTIBLE TO DAMAGE — DO NOT
SCRATCH WHILE HANDLING OR WHILE
RE-INSTALLING THE GLASS DOOR
FRAME.
WARNING: NEVER OPERATE THE APPLI-
ANCE WITHOUT THE FRONT GLASS EN-
CLOSURE PANEL IN PLACE AND SECURE.

Step 10. BURNER ADJUSTMENTS

Flame Appearance and sooting
Proper flame appearance is a matter of taste. Gen-
erally, most people prefer the warm glow of a yellow
to orange flame. Appliances operated with air shut-
ter openings that are too large will exhibit flames that
are blue and transparent. These weak, blue and
transparent flames are termed anemic. If the air
shutter opening is too small 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 entering the air shutter opening. To
achieve a warm yellow to orange flame with an
orange body that does not soot, the shutter open-
ing must be adjusted between these two extremes.
No smoke or soot should be present. Reposi-
tion the logs if flames impinge on any of them.
If the logs are properly positioned and sooting
conditions exist, the air shutter opening on
the main burner tube should be adjusted.
Normally, the more offsets in the vent system,
the greater the need for the air shutter to be
opened further.
WARNING: AIR SHUTTER ADJUSTMENT
SHOULD ONLY BE PERFORMED BY A
QUALIFIED PROFESSIONAL SERVICE
TECHNICIAN.
IMPORTANT: ENSURE THAT THE FRONT
GLASS PANEL IS IN PLACE AND SEALED
DURING ADJUSTMENT.
Burner Adjustment
CAUTION: THE ADJUSTMENT ROD AND
NEARBY APPLIANCE SURFACES ARE HOT.
EXERCISE CAUTION TO AVOID INJURY WHILE
ADJUSTING FLAME APPEARANCE.
To adjust the flame, move the adjustment rod
(located in the lower control area) up or down
to increase or reduce the air shutter opening,
respectively. Initially, always position the air
shutter to the factory setting (the minimum
air opening position) as shown in Figure 54 .
This can be done by pulling the adjustment
rod all the way down. Allow the burner to
operate for at least 15 minutes. Observe the
flame continuously. If it appears weak or sooty
as previously described, adjust the air shutter
by pushing or pulling on the adjustment rod
until the flame appearance is as desired.
F
A
C
S
G
s a
M
o
e d
s l
y T
e p
S
n i
h c
N
. t a
/ 1
M
P
D
- T
3 3
8 2
P
o r
. p
/ 3
N
. t a
/ 1
M
P
D
- R
3 3
8 2
P
o r
. p
/ 3
N
. t a
/ 1
M
P
- D
5 3
0 3
P
o r
. p
/ 3
N
. t a
1
M
P
- D
0 4
5 3
P
o r
. p
N
. t a
1
M
P
- D
5 4
0 4
P
o r
. p
Figure 54
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
The adjustment rod and associated adjustable
air shutter is patented technology. Flame ad-
justments can be made quickly and accurately
to taste without the need of disassembling the
appliance and waiting for 30 minutes after
each adjustment.
Note: If the flame still appears anemic with
the air shutter closed all the way against the
stop (usually a result of lengthy vertical runs),
turn the appliance off, turn the gas supply off,
wait for the parts to cool, remove the glass
door and logs to access the air shutter. The
shutter is prevented from actually closing all
the way by an adjustment set screw (see
Figure 54). Remove this screw using a 1/4
inch nut driver. Reinstall the logs and glass
door, turn the gas back on and then restart the
appliance. After 30 minutes, reobserve the
flame. Adjust the air shutter as previously
described.
When satisfied that the appliance operates
properly, proceed to finish the installation.
Leave the control knob in the ON position and
the remote switch OFF. Close the lower control
compartment door.

Step 11. HOOD INSTALLATION

All of these appliances must have hoods
installed prior to operating.
On all clean face units, slide the hood into the
T
O
R
Y
A
R I
slots on the lower edge of the radiant panel
H
U
T
E T
R
(Figure 55 ).
E
T T
N I
G
s e
(
m
m
)
On louvered face units, slide the hood into the
2 3
(
. O
) 8
slots on the lower edge of the cabinet top
6 1
4 (
7 .
) 6
(Figure 56 ).
2 3
(
. O
) 8
6 1
4 (
7 .
) 6

FINISHING REQUIREMENTS

2 3
(
. O
) 8
Wall Details
6 1
4 (
7 .
) 6
8 /
(
. 3
) 2
Complete finished interior wall. To install the
1
2 /
1 (
) 3
appliance facing flush with the finished wall,
8 /
(
. 3
) 2
position framework to accommodate the thick-
1
2 /
1 (
) 3
ness of the finished wall (see Figure 55, and
Figure 56 ).
25

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