10
LENNOX HEARTH PRODUCTS • MERIT PLUS
®
DIRECT VENT GAS FIREPLACES (MPD33/35/40/45) • INSTALLATION INSTRUCTIONS
Model
A
B
C
d
E
MPdT33
33-1/4
33-1/4
---
37-3/4
12-7/8
845
845
---
959
327
MPdR33
in.
33-1/4
33-1/4
19-5/8
---
12-7/8
mm
845
845
498
---
327
MPd35
in.
35-1/4
35-1/4 21-11/16 39-3/4
16
mm
895
895
551
1010
406
MPd40
in.
40-1/4
40-1/4 26-11/16 44-3/4
16
mm
1022
1022
678
1137
406
MPd45
in.
45-1/4
40-1/4 26-11/16 44-3/4
16
mm
1149
1022
678
1137
406
A
B
D
7
(178)
5-1/8
12-1/8
(308)
10-1/2
(
267
)
C
VENT FRAMING:
TOP VENT WITH ONE
90
°
ELBOW
VENT FRAMING:
REAR VENT WITH
NO ELBOWS
Framing should be
constructed of 2x4
or larger lumber.
Inches (mm)
E
(130)
(130)
7
(308)
(178)
1/2
A
5-1/8
12-1/8
Dimension “E” is the required framing depth when the
finish material (drywall) thickness is 1/2 in. (13mm).
G
H
Top View
Concentric Flue:
Flue 4-1/2” (114 mm);
Combustion Air
7-1/2” (190 mm).
See Notes [1] and [2].
Rear/Side
Framing
Spacers
Notes:
[1]
MPD
models have a top and rear vent.
MPDR
models
have a rear vent only.
MPDT
models have a top vent only.
[2] Collars protrude one inch on
MPDT33
and
MPDR33
models.
J
F (rear vent
models only)
N
1/2 (13)
1-5/8 (42)
L
K
Gas Inlet (either
side and bottom)
Electrical Inlet
2-3/4" x 2"
(70 x 51 mm)
Cover Plate
with Knockout
Right Side View
M
See Note [2].
6 (152)
1-3/8 (35)
Optional Electrical Inlet
Knockout requiring a
Field-Provided Junction
Box (either side)
E
B
D
C
Front View
3 (76)
A
Header
Spacing
Top
Standoffs
Vertical Venting through the Ceiling
Frame ceiling opening:
Use a plumb line from the ceiling above the appliance to locate center of the vertical run. Cut and/or frame an opening,
10-1/2" x 10-1/2" (267 mm x 267 mm) inside dimensions, about this center mark
(see Figure 20)
.
Notes
diagrams, illustrations and photographs are not to scale. Consult installation
instructions. Product designs, materials, dimensions, specifications, colors,
and prices are subject to change or discontinuance without notice.
Thermal Efficiency (%)
Fireplace
Model
Natural Gas
Propane
AFUE EnerGuide
(P4)
AFUE EnerGuide
(P4)
MPdT33
62
45
64
49
MPdR33
61
53
64
55
MPd35
62
53
60
55
MPd40
67
59
67
60
MPd45
67
59
67
59
Based on CSA P.4.1-09
Figure 12 - Fireplace and Framing Specifications
Framing
Model
A
B
C
d
E
F
G
H
J
K
L
M
N
MPd33
in.
33-1/8
30-1/8
17
27-1/2
33-1/8
19-5/8
21-1/2
10-3/4
6-13/16
3
8-11/32
2-3/4
13
mm
841
765
432
699
841
498
546
273
173
76
212
70
330
MPd35
in.
35-1/8
32-1/8
19
29-1/2
35-1/8 21-11/16 24-7/8
12-7/16
9
3
9
3
16
mm
892
816
483
749
892
551
632
316
220
76
220
76
406
MPd40
in.
40-1/8
37-1/8
24
34-1/2
40-1/8 26-11/16 29-7/8
14-15/16
9
3
9
3
16
mm
1019
943
610
876
1019
678
759
379
220
76
220
76
406
MPd45
in.
40-1/8
37-1/8
24
39-1/2
45-1/8 26-11/16 34-7/8
17-7/16
9
3
9
3
16
mm
1146
943
610
1003
1146
678
886
443
220
76
220
76
406
