Isokern Magnum 36 Owner's manual

Isokern®MAGNUM®Fireplace
and DM chimney system
Installation, Operation, Maintenance and Owner’s Manual
MAGNUM MODELS 36, 42, 48, 60 and 72
A PRODUCT OF EARTHCORE INDUSTRIES, INC.
Important: This manual contains assembly rules, installation steps and guidelines, and use and maintenance instructions for the MAGNUM Series
fireplace and chimney system. This manual must become the property of and be reviewed by all current and future users of this product. It is the respon-
sibility of the general contractor and the installer of this product that the instructions in this manual are followed exactly and, further that any allowed
gas log appliance used in this product be installed in strict accordance with NFPA 58, NFPA 54/ANSI Z223.1 and the gas log manufacturer’s explicit
installation, sizing and operation instructions. It is the responsibility of the general contractor to provide adequate clearances from all firebox surfaces as
specified in this manual.
Keep This Manual for Future Use
Be Sure to Read Entire Manual Before Beginning Construction.
Contents of this manual may change without prior notification.
SBCCI NO. 9626 NYC-MEA 241-90-E
ICC Report NO. ER5017 LA RR NO. 25483
Revised January 1, 2007 (w)
INTERTEK TESTING SERVICES REPORT NO. 632-912500 / 3082504-T1
THIS MANUAL CAN ONLY BE REPRODUCED IN ITS ENTIRETY
THIS FIREPLACE IS DESIGNED for USE with
SOLID WOOD LOGS, PLUMBED PROPANE
(LP) or NATURAL GAS, ONLY
DO NOT USE or STORE GASOLINE or OTHER
FLAMMABLE LIQUIDS or GASES IN or NEAR
the ISOKERN FIREPLACE
WARNING: If the information in this manual is not followed exactly, a fire or explosion may
result causing property damage, personal injury or loss of life.
© 2005 ECI
Sep 03, 2008
SH

1 / 60
TABLE OF CONTENTS
General Information....................................................................................................................................................................page 2
Intended Use Statement .......................................................................................................................................................................3
Safety Instructions ...............................................................................................................................................................................4
Warnock-Hersey Listing Label............................................................................................................................................................5
Assembled Firebox Dimensions .................................................................................................................................................... 6 - 8
Models 36, 42, 48 .....................................................................................................................................................................6
Models 60 and 72....................................................................................................................................................................18
Component List and Dimensions .................................................................................................................................................. 7 - 9
Models 36, 42, 48 .....................................................................................................................................................................7
Models 60 and 72......................................................................................................................................................................9
Required Clearances to Combustibles...............................................................................................................................................10
Assembly Instructions................................................................................................................................................................ 12 - 27
Models 36, 42, 48 ........................................................................................................................................................... 12 - 15
Model 60 ......................................................................................................................................................................... 16 - 20
Model 72 ......................................................................................................................................................................... 21 - 25
Access Modification ...............................................................................................................................................................26
Fire Brick Installation .............................................................................................................................................................27
Flush Wall Finish Detail. ...................................................................................................................................................................28
Required Clearances (when sheathing protrudes beyond front of firebox) ......................................................................................29
Required Clearances to Combustible Framing..................................................................................................................................30
Required Clearances to Insulation and Vapor Barriers .....................................................................................................................31
Flush Wall Fire Brick Finish Detail...................................................................................................................................................32
Finish Facing Detail...........................................................................................................................................................................33
Interior Full Masonry Veneer Finished Fireplace Fronts .......................................................................................................... 34 - 35
Interior Full Masonry Veneer Finished Fireplace Fronts Details ...........................................................................................35
Non Combustible Facing Requirements & Clearance to Combustible Trim............................................................................ 36 - 37
Models 36, 42, 48 ...................................................................................................................................................................36
Models 60 and 72....................................................................................................................................................................37
Concrete Support ...............................................................................................................................................................................38
DM Chimney System ................................................................................................................................................................ 39 - 50
General Information................................................................................................................................................................39
Component List.......................................................................................................................................................................40
Component Weight..................................................................................................................................................................41
Installation...................................................................................................................................................................... .42 - 49
Lateral Support...............................................................................................................................................................43
Offset Block ...........................................................................................................................................................43 - 45
Brick Ledge............................................................................................................................................................ 46 - 48
Crown Caps....................................................................................................................................................................49
Height Requirements...............................................................................................................................................................50
Structural Support ...................................................................................................................................................................51
Common Chimney Terminations ............................................................................................................................................52
Class "A" Metal Flue.........................................................................................................................................................................53
Summary.................................................................................................................................................................................... 54 - 55
Notes ......................................................................................................................................................................................... 56 - 58
Warranty

2 / 60
General Information
The MAGNUM fireplace and DM 54 chimney system is
a prefabricated, refractory, modular masonry fireplace and
chimney system designed for field assembly. The system
consists of interlocking precast parts which are glued togeth-
er with a masonry adhesive.
The parts of the MAGNUM fireplace and DM 54 chim-
ney system are precast using a proprietary mixture of vol-
canic pumice aggregate and masonry cement and includes
all the parts necessary for assembly of a complete firebox,
smoke dome and chimney system.
Each MAGNUM precast fireplace component is
designed for a specific part of the fireplace such that only
one means for assembly is possible.
The firebox and smoke dome are designed to be fit-
ted with a traditional cast iron, poker-style throat damper.
However, chimney top dampers are an option.
The MAGNUM fireplace requires a standard refractory
fire brick liner be applied to the interior of the firebox. Fire
brick must be a minimum one and one-eighth inch (1-1/8")
thick excpet with MAGNUM models 60 and 72.
The MAGNUM fireplace is available in five sizes:
thirty-six inch (36”), forty-two inch (42”), forty-eight inch
(48”), sixty inch wide (60") and seventy-two inch (72")
wide. All units have a thirty-six inch (36”) opening height.
The only parts which differ among the available sizes are
width related pieces: the base plate, firebox back wall, front
and back smoke dome components, and the smoke dome top
plate. All units use the same side wall pieces.
The DM 54 chimney system is a dual module masonry
chimney system. The basic chimney consists of an outer cas-
ing block and an inner liner with a fourteen inch (14”) diam-
eter flue hole. The chimney components are field assembled
using Earthcore Mortar to glue the components together.
The DM 54 chimney system also includes an offset
chimney block component, used to create offsets to the ver-
tical run of the chimney. A brickledge component is avail-
able, designed to support chimney top brick veneer finishes.
Prefabricated masonry chimney termination caps are also
available.
The various MAGNUM fireplace and DM 54 chimney
components will be described and illustrated in the follow-
ing pages. Close attention should be paid to each compo-
nent group’s specifications and installation requirements as
described in this manual.
Important: Due to heat and weight issues, MAGNUM
fireplace and DM chimney system installations require that
the system be built upon a non-combustible concrete slab
supported to footings with concrete or steel and designed to
carry the total weight of the Isokern fireplace and chimney
system.
Minimum overall height requirements for the MAGNUM
fireplace and chimney system is eighteen feet (18’-0”) when
the chimney is straight and twenty-one feet (21’-0”) when
a chimney is offset. Maximum overall height is eighty-two
feet (82’ - 0”). However, installations over fifty-seven feet
(57' - 0") will require additional support.

3 / 60
Intended Use Statement
Intended Product Use Statement:
The MAGNUM fireplace and DM 54 chimney system
are intended to burn solid wood fuel, propane or natural
gas.
This fireplace is not designed to sit directly on a com-
bustible floor system.
This fireplace is intended for use as a supplemental heat
source only and is not intended for heavy use as a primary
heating system.
Overfiring, abusive burning or mistreatment will void
any claims (eg. burning construction debris or other highly
flammable material; tossing, kicking or otherwise forcing
logs into the firebox will void any claims).
MAGNUM fireplace and DM 54 chimney systems are
conventional fireplaces designed to appear like traditional
masonry fireplaces. MAGNUM fireplace and DM 54 chim-
ney system units are intended for installation in residential
homes and other buildings of conventional construction.
Note(s): The local authority having code jurisdiction should
be consulted before installation to determine the need to
obtain a permit.
Important areas of concern with the installation of
these fireplaces are: construction of proper load bearing
foundation and concrete support slab; code required hearth
extension substrates and supports; proper assembly of
components; clearance to combustible materials; height of
chimney; and, techniques employed in applying finishing
materials to the fireplace opening and hearth extension.
Each of these important topics will be covered in detail
throughout this manual. Installation personnel must give
special attention to each topic as the installation progresses.
All work performed on, near and adjoining the fireplace and
chimney installation must meet or exceed the specifications and
requirements in this manual and the prevailing local building code.
Subsequent renovations, additions of cabinets and storage
spaces in the enclosure surrounding the fireplace are also limited to
the specifications in this manual and to the prevailing local building
code.
Isokern is not responsible for other construction work around
the fireplace unit.
Note(s): Do not scale drawings. Illustrations in this manual are
not to scale and are intended to show “typical” installations.
Nominal dimensions are given for design and framing refer-
ence only, since actual installations may vary due to job spe-
cific design preferences. Always maintain the stated minimum
clearances to combustible materials. Do not violate any specific
installation requirements.
The MAGNUM fireplace and DM 54 chimney system is
tested and listed by Warnock Hersey (Intertek Testing Service)
- Report No. 632-912500 and Report No. 3082504-T1 - to UL
127-1999, UL 1777 and UL 103HT.
MAGNUM fireplace systems are also designed for installa-
tion in accordance with the National Fire Protection Association
Standard for chimneys, fireplaces, vents and Solid Fuel-Burning
Appliances (NFPA 211).
MAGNUM fireplaces are not listed for use with fireplace
inserts.

4 / 60
1. Before starting the MAGNUM fireplace and DM 54
chimney installation, read these installation instructions
carefully to be sure you understand them completely. Failure
to follow them could cause fireplace malfunction resulting
in serious injury or property damage.
2. Always check local building codes governing fireplaces
and fireplace installations. The MAGNUM fireplace and
DM chimney installation must comply with all local, region-
al, state and national codes and regulations.
3. MAGNUM fireplace and DM 54 chimney systems are
intended for use in any application where a traditional
masonry type fireplace would apply. The chimney system
must always vent vertically to the outside of the building.
4. Creosote and soot formation and the need for removal:
When wood is burned slowly, it produces tar and other
organic vapors which combine with expelled moisture to
form creosote. The creosote vapors condense in the rela-
tively cool chimney flue of a slow burning fire. As a result,
creosote residue accumulates on the flue lining. When
ignited this creosote makes an extremely hot fire.
Because of creosote and soot buildup it is necessary
to inspect and clean the fireplace and chimney prior to use
and periodically during the heating season. Cleaning of the
fireplace and the chimney system should be done annually at
a minimum. In colder climates, chimney cleaning may need
to be done periodically throughout the heating season.
5. Before servicing, allow the fireplace to cool. Always shut
off any electricity or gas to the fireplace while working on
it.
6. Use only solid fuel or natural or LP gas log sets in this
unit. Do not use artificial wax based logs, chemical chimney
cleaners or flame colorants in this fireplace.
7. Never use gasoline, kerosene, gasoline-type lantern fuel,
charcoal lighter fluid, or similar liquids to start or “freshen
up” a fire in this fireplace. Keep all flammable liquids at a
safe distance from the fireplace.
8. Always keep the flue damper open when heat is present
in the fireplace.
9. Do not use a fireplace insert or any other product not
specified for use with the MAGNUM fireplace and DM 54
chimney systems unless written authorization is given by
Isokern. Failure to heed this warning may cause a fire hazard
and will void the Isokern warranty.
10. This fireplace is not intended to heat an entire home or
to be used as a primary heat source. It is designed to ensure
homeowner comfort by providing supplemental heat to the
room.
11. Always ensure that an adequate supply of replacement
combustion air from the outside of the house is accessible to
the fire to support normal combustion. Fireplaces consume
large volumes of air during the normal firing process. In the
event the home is tightly sealed and has modern energy effi-
cient features, the optional combustion air supply kits may
not provide all the air required to support combustion and
the proper flow of combustion gases up the chimney.
The manufacturer is not responsible for any smoking or
related problems that may result from the lack of adequate
air supply flowing into the house. It is the responsibility of
the builder/contractor to ensure that adequate air supply has
been provided for the fireplace.
12. “Smoke free” operation is not warranted nor is the
manufacturer responsible for inadequate system draft caused
by mechanical systems, general construction conditions,
inadequate chimney heights, adverse wind conditions or
any unusual environmental conditions or factors beyond the
manufacturer’s control.
13. CAUTION:When used with the MAGNUM fireplace
system, all gas log sets must be operated with the damper
clamped in the open position. This includes unlisted “vent
free” log sets. Only listed “vent free” log sets may be oper-
ated with the damper in the closed position.
14. When in doubt about a component’s usability - has vis-
ible or suspected physical damage - consult your Isokern
distributor or authorized Isokern representative for advice.
15. Modification to MAGNUM components not mentioned
in this manual may void warranties, listings and approv-
als and could result in an unsafe and potentially dangerous
installation.
Alterations to the MAGNUM firebox are not allowed
without prior written approval and instructions from
Earthcore Industries, Inc.
16. Wherever insulation is used, the MAGNUM fireplace
must not be placed directly against it. Keep all insulation or
vapor barriers a minimum of three inches (3”) away from all
fireplace and chimney components.
It is recommended that insulation and vapor barriers, if
used, first be covered with gypsum board, plywood, particle
board or other material to assure that insulation and vapor
barriers remain in place.
17. WARNING – DO NOT PACK REQUIREDAIR SPACES
WITH INSULATION OR OTHER MATERIALS.
18. Never leave children unattended when there is a fire
burning in the fireplace.
19. Burning some fuels (such as charcoal) can be hazardous
due to the possibility of producing carbon monoxide, a col-
orless, odorless gas. Early signs of carbon monoxide poising
resemble flue symptoms, including headaches, dizziness or
nausea. Over exposure to carbon monoxide can lead to ill-
ness and death.
It is strongly recommended to install smoke and carbon
monoxide alarm / detector devices wherever fireplaces are in
use.
Safety Instructions

5 / 60
WARNOCK HERSEY LISTING LABEL
- FACSIMILE -
Isokern Fireplace and Chimney Systems are tested and listed to UL standards:
UL 127, ULC S610, UL 1777 and UL 103HT.
The listing label shown in Figure 1 above, outlines the listed clearances to combustibles and indicates that the units are suitable
for use with solid fuel or listed gas appliances. Refer to the manufacturer’s installation manual for detailed description of clear-
ances to combustibles and all other installation information.
A metal listing label similar to that shown above is affixed to each MAGNUM unit.
Do not remove the listing label from the MAGNUM unit.
Prior to beginning installation, contact local building official to determine the need to obtain a permit.
Figure 1
X

6 / 60
Model Minimum Framing Weight
36” 46” W x 71” H x 29½” D 1360 lbs.
42” 52” W x 71” H x 29½” D 1450 lbs.
48”
A
43”
48½”
53”
B
28”
28”
28”
C
69½”
69½”
69½”
D
38”
38”
38”
E
39”
44½”
49”
F
24¾”
29 ”
G
32 ”
43”
H
25¼”
25¼”
25¼”
I
4¾”
4¾”
4¾”
J
5”
5”
5”
K
8”
8”
8” 56” W x 71” H x 29½” D 1600 lbs.
B A
C
HG
K
I
B
E
D
F
E
J
TOP PLATE SMALL
Part
No.:
M77
M77
Fireplace
Size:
36” W
42” W
Quantity:
1
1
TOP PLATE LARGE
Part
No.:
M81
Fireplace
Size:
48” W
Quantity:
1
25 ¼”
10 ¾”
4 ¾”
25 ¼”
10 ¾”
43”
4 ¾”
N
M
Right Section Front Elevation
Top Plan View
Plan Section
19¼”
M
17 ¼”
17 ¼”
17 ¼”
N
10 ¾”
10 ¾”
10 ¾”
32 ”
32
Assembled Firebox and Smoke Dome Dimensions - Models 36, 42, 48
Firebox and Smoke Dome Components List - Models 36, 42, 48

7 / 60
Components List & Dimensions - Models 36, 42, 48
Isokern reserves the right to make changes at any time, without notice, in design, materials and specifications and also to dis-
continue styles and products. Please call 1-800-642-2920 for an Isokern dealer near you.
H
53”
43”
43”
2”
28”
9 ½”
9 ½”
28”
3”
F
28”
3”
16”
16”
4”
4”
8”
G
5”
3”
25 ¼”
16”
Front of
Smokedome
(above)
Part
No.:
M61
M61
M61
Fireplace
Size:
36” W
42” W
48” W
Quantity:
2
2
2
Part
No.:
M62
M63
Fireplace
Size:
42” W
48” W
Quantity:
1
1
Part
No.:
11
11
Fireplace
Size:
36” W
42” W
Quantity:
2
2
Part
No.:
13
Fireplace
Size:
48” W
Quantity:
2
Part
No.:
M60
M60
M60
Fireplace
Size:
36” W
42” W
48” W
Quantity:
8
8
8
Part
No.:
M65
M66
M67
Fireplace
Size:
36” W
42” W
48” W
Quantity:
4
4
4
Part
No.:
M64L
M64L
M64L
Fireplace
Size:
36” W
42” W
48” W
Quantity:
1
1
1
Part
No.:
M64R
M64R
M64R
Fireplace
Size:
36” W
42” W
48” W
Quantity:
1
1
1
Part
No.:
M68
M69
M70
Fireplace
Size:
36” W
42” W
48” W
Quantity:
2
2
2
TOP - SLOPING
TOP - BIG
TOP - MEDIUM
Model
Model 42” & 48”
BASE PLATE
Model 36”
BASE PLATE
F
42” 48½”
48” 53”
SIDE WALL
DAMPER SUPPORT (LEFT)
DAMPER SUPPORT (RIGHT)
DAMPER SUPPORT
(FRONT & REAR)
M65, M66, M67 - stacked four (4) high
Model G
36” 26 ¾”
42” 32 ¼”
48” 37”
BACK WALLS
Model H
36” 43”
42” 48½”
48” 53”
Part
No.:
34
34
34
Fireplace
Size:
36” W
42” W
46” W
Quantity:
2
2
2

8 / 60
Model Minimum Framing Weight
60” 77” W x 87” H x 29½” D 2700 lbs.
72” 89” W x 87” H x 29½” D 2900 lbs.
B
28”
28”
D
38”
38”
H
25 ¼”
25 ¼”
I
4 ¾”
4 ¾”
J
5”
5”
K
8”
8”
N
M
Right Section Front Elevation
Top Plan View
Plan Section
F
62”
50”
M
17 ¼”
17 ¼”
N
10 ¾”
10 ¾”
A C
85 ½”
E G
54”
C
D
H G
I
K
F
E
E
BA
J
B
65 ½”
69 ½”
81 ½”
85 ½”73 ½”
85 ½”
Assembled Firebox Dimensions - Models 60 and 72

9 / 60
Components List & Dimensions - Models 60 and 70
48½”
53”
43”
2”
28”
9 ½”
9 ½”
28”
3”
16”
16”
4”
4”
8”
G
5”
3”
25 ¼”
16”
Part
No.:
M61
M61
Fireplace
Size:
60” W
72” W
Quantity:
4
4
Part
No.:
11
11
Fireplace
Size:
60” W
72” W
Quantity:
6
2
Part
No.:
13
Fireplace
Size:
60” W
Quantity:
2
13 72” W 6
Part
No.:
M60
M60
Fireplace
Size:
60” W
72” W
Quantity:
8
8
Part
No.:
M66
M67
Fireplace
Size:
60” W
72” W
Quantity:
8
8
Part
No.:
M64L
M64L
Fireplace
Size:
60” W
72” W
Quantity:
1
1
Part
No.:
M64R
M64R
Fireplace
Size:
60” W
72” W
Quantity:
1
1
Part
No.:
M69
M69
Fireplace
Size:
60” W
72” W
Quantity:
4
4
TOP - SLOPING
TOP - BIG
TOP - MEDIUM
BASE PLATE
SIDE WALL
DAMPER SUPPORT (LEFT)
DAMPER SUPPORT (RIGHT)
DAMPER SUPPORT
Model G
60” W 32¼”
72” W 37”
BACK WALLS
Part
No.:
34
34
Fireplace
Size:
60” W
72” W
Quantity:
4
4
TOP PLATE SMALL
Part
No.:
M77
M77
Fireplace
Size:
60” W
72” W
Quantity:
2
2
25 ¼”
10 ¾”
4 ¾”
32

10 / 60
0” Clearance
1 ½” min.
No wood underpinings beneath
substrate slab or hearth extension
Zero clearnce to
the front of smoke dome
Combustible framing
Hearth extension
Required Clearance to Combustibles
The MAGNUM fireplace and DM chimney system is tested
and listed for installation with "clearance to combustibles"
as follows:
One and one half inch (1-1/2”) clearance at the
MAGNUM firebox back wall (Figure 3), the firebox side
walls, the smoke dome back wall and smoke dome side
walls (See Figures 4 & 5, page 11);
Zero inch (0”) clearance at the smoke dome front wall.
(Figure 3)
Zero inch (0”) clearance at all DM 54 chimney compo-
nents. (Figure 2)
Important: “Combustibles” are defined as “normal con-
struction materials” and are considered to be: wood framing
materials, particle board, mill board, plywood sub-flooring,
plywood paneling and wood flooring.
Sheathing materials, such as plywood, particle board
and drywall may cover the smoke dome front at zero inch
(0”) clearance.
All combustible sheathing materials that protrude
beyond front of firebox must be held eight inches (8”) away
from the sides of the firebox opening and eight inches (8”)
above the top of the firebox opening.
Drywall must be cut two inches (2”) back from the fire-
box opening sides and eight inches (8”) above the top of the
opening.
CAUTION: Maintain a minimum of three inch (3”) clear-
ance to insulation and vapor barriers.
CAUTION: Combustible objects, such as furniture, placed
in front of the fireplace, must be kept a minimum of forty-
eight inches (48”) from the fireplace opening.
Note(s):
1. The MAGNUM fireplace is not rated for installation
on a combustible floor system. Isokern units must sit upon
a concrete support slab designed to bear the total installed
weight of the MAGNUM fireplace and DM chimney sys-
tem. See page 10 for additional details. These support slabs
can have no wood underpinnings. (Figure 2)
2. Concrete support slabs for MAGNUM fireplaces
must provide the noncombustible hearth extension substrate
needed to support the code required noncombustible hearth
extension finish materials. (Figures 2 and 3)
3. All MAGNUM fireplaces shall have hearth exten-
sions of approved noncombustible material such as brick,
tile, or stone that is properly supported and with no combus-
tible material against the underside thereof. Wooden forms
used during the construction of hearths and hearth exten-
sions shall be removed when the construction is complete.
4. If a raised fireplace floor and raised hearth extension
are preferred, the raised underlying structure must be built
of noncombustible material and must sit on noncombustible
substrate.
Figure 2
Figure 3

11 / 60
B
Framed
Opening
29½”
min.
A
C
D
B
A
Framed Opening
Rough Framing Dimensions
Corner Location Layout
Rough Framing Dimensions (Figure 4)
Model Width Height Depth
A B C
Model 36 46” 71” 29.5”
Model 42 52” 71” 29.5”
Model 48 56” 71” 29.5”
Model 60 77” 87” 29.5”
Model 72 89” 87” 29.5”
Note(s):
1. “B” includes the MAGNUM three inch (3”) thick
base plate. “B” is reduced by three inches (3") if the base
plate is eliminated to create a “flush hearth”.
2. “Raised hearth” requires additional rough opening
height at “B” equal to the height of the raised hearth detail.
3. Rough framing dimension for depth “C” allows for
the required one and one-half inch (1-1/2”) clearance at the
back of the MAGNUM fireplace.
4. Keep all insulation and insulation products three
inches (3”) away from all MAGNUM surfaces.
Figure 4
Figure 5
The following chart of dimensions is intended to aid in the
positioning of an MAGNUM fireplace in a corner condi-
tion where the DM 54 chimney must turn forty-five (45°)
degrees to align with overhead framing.
Firebox A B C D
Model 36 46” 51” 34” 72”
Model 42 52” 55” 39” 75”
Model 48 56” 61” 42” 79”
Model 60 77” 69” 56” 91”
Model 72 89” 75” 64” 105”
To turn flue forty-five degrees (45°), first set one offset
block on the firebox so that the chimney offsets three inches
(3") toward the back of the firebox. (Figure 5)
Set a DM 54 outer casing onto this offset block so that
the outer casing is at forty-five degrees (45°) to the firebox
and square to the overhead framing system. Run the vertical
DM 54 chimney through the overhead framing.
More offset blocks can be used - if necessary to align
with overhead framing - before running the vertical DM 54
chimney outer casing and liner.
Note(s): Support the third offset down to footings and at
each third offset block thereafter (see page 45).

12 / 60
Earthcore
Mortar
Shim if required
to acheive
correct height
Fully grout the gap
Assembly Instructions - Models 36, 42, 48
General Isokern Assembly Instructions:
Earthcore Mortar (a thin-set type masonry adhesive) is
used to glue all Isokern components together during field
assembly of the unit. The mortar is supplied dry, in 5 gallon
buckets.
Earthcore Mortar is mixed with clean water to a smooth,
workable texture, without lumps or dry pockets and of a
“toothpaste” consistency. This mixture is suitable for appli-
cation onto Isokern components by using a masonry grout
bag supplied with the unit.
Attention should be paid that the mortar mixture is not
too thin or runny, as this will not allow the mortar to reach
its maximum bonding strength.
Note(s):
1. Do not mix Earthcore Mortar with spirits or anti-
freeze agents.
Earthcore Mortar is squeezed from a grout bag onto the
contact surfaces of the Isokern components as they are fitted
together.
It is important that a one-half inch (1/2") bead of mortar
on all the components’ contact surfaces is applied at about
one-half inch (1/2") in from all edges of the contact surface
of the component. (Figure 7)
When setting the next component onto the mortared
contact surface of the first component, some mortar should
squeeze out along the face of the entire joint as a sign of
complete and proper sealing of the joint.
On broader contact surfaces, it is advisable to apply sev-
eral additional one-half inch (1/2") beads of the Earthcore
Mortar to the area to assure proper sealing of the joint.
Properly mortared firebox and smoke dome assembly
requires approximately 5 gallons (dry measure) of Earthcore
Mortar. (Figure 6)
Broken Components: Components broken into 2 or 3
pieces can be repaired by using Earthcore Mortar along the
break line as the component is set into place. Components
broken into multiple small pieces should be discarded and
replaced.
Leveling And Aligning Components: Be sure to assemble
all MAGNUM components level and flush with adjoining
components.
Earthcore Mortar is not intended to create a mortar joint
of any thickness. Therefore leveling and alignment adjust-
ments are made by the use of small plastic shims (supplied
with the unit).
The shims can be inserted under a component to level
and align it with adjacent MAGNUM components (Figure
8). Be sure to re-grout any and all gaps resulting from shim
insertion to maintain components to full bearing.
Note(s):
1. Earthcore Mortar can be troweled over the face of a
joint where it has squeezed out while setting components.
It is not intended that the exposed faces of the MAGNUM
components be completely covered with the mortar.
Figure 6
Figure 7
Figure 8

13 / 60
Earthcore Mortar
Baseplates
First course
side wall
Earthcore Mortar
Flush
hearth
Raised
hearth
Figure 9
Figure 10
Figure 11
Figure 12
Step 1: The MAGNUM base plate is supplied in two pieces
for model 36 and in three pieces for models 42 and 48.
Set the MAGNUM base plate components in a full bed of
Earthcore Mortar flat on a proper concrete support founda-
tion. Be sure to mortar the base plate pieces together (Figure
9).
Do not set the MAGNUM base plate so that it is in
span. Level the MAGNUM base plate by floating it in a bed
of Earthcore Mortar to full bearing against the underlying
noncombustible support surface.
Note(s):
1. If the design preference is for a “flush hearth” (fire-
place floor flush with the room’s floor), the base plate can
be omitted from the assembly and the firebox walls built
directly on the concrete support slab. The fire brick floor of
the firebox is then set directly to the concrete support slab.
This makes the fireplace finished fire brick floor approxi-
mately one and one-half inches (1-1/2") above the top of the
concrete support slab (Figure 10).
2. If the design preference is for a raised hearth (floor
of the fireplace elevated above the room’s floor), then the
MAGNUM base plate can be set on a concrete block plat-
form that is built up to the desired raised hearth height on the
concrete support slab.
When calculating raised hearth height be sure to allow
for the three inch (3”) thick base plate plus the one and one-
half inch (1-1/2") thick fire brick floor in addition to the
height of the concrete block platform. (Figure 11)
For all “raised hearth” construction where concrete
block are used to create the raised platform, it is necessary
to use the MAGNUM base plate. Be sure to mortar the con-
crete block platform together.
CMU used for base plate support should be rated ASTM
90.
Step 2: Set the first course of the firebox back wall and side
walls into place.
It may be convenient to dry set the first course of side
wall and back wall into place on the Isokern base plate and
then to trace their position on the base plate with a pencil.
(Figure 12)
After outlining the dry set pieces, remove them and
apply Earthcore Mortar to the areas traced on the base plate
where the side walls and back wall are to sit. By doing this,
the first layer of Wall components can be set directly into
mortar already applied to the proper areas on the base plate.
(Figure 12)
Be sure to put Earthcore Mortar on the contact surfaces
of the vertical joints where the side wall and back wall com-
ponents connect. (Figure 13)
Note(s):
1. At all component placement, be sure to mortar all
component contact surfaces with Earthcore Mortar. Check
for complete sealing of each contact joint while assembly
progresses.
Step 3: Continue assembly of the second, third and fourth
courses of the firebox side wall and back wall. Apply mortar
Assembly Instructions - Models 36, 42, 48 (cont.)

14 / 60
Earthcore
Mortar
First damper
support in place
Two courses
backwall
Cast iron
damper
Front damper
support
Earthcore
Mortar
Earthcore
Mortar
Figure 13
Figure 14
Figure 15
Assembly Instructions - Models 36, 42, 48 (cont.)
to the top of each layer of wall components, then set the next
course above into place.
Be sure to mortar all vertical joints of the side wall to
back wall connection when setting each component to its
mate. (Figure 13)
Look for some mortar to squeeze out along the joints of
all contact surfaces as sign that the joint is thoroughly sealed
with the approved mortar.
Step 4: When all of the MAGNUM firebox wall compo-
nents are set, check the top surface of the firebox for level.
If necessary, adjust the top surface of the box assembly for
level by inserting a shim between the lowest wall component
and the top surface of the MAGNUM base plate. (Figure 8)
Any gap created under the wall components during the
shim leveling process must be filled with mortar to full bear-
ing against the base plate.
Step 5: Make sure that the firebox assembly has been set
level and square. Adjust as required while the mortar is still
wet.
Make a final inspection of all contact joints in the fire-
box assembly to be sure they are properly sealed. Fill any
and all gaps in the assembly, as necessary, with the approved
mortar.
Step 6: The MAGNUM comes with an eight inch (8”) thick
damper plate, a four piece component group that is to be
assembled on top of the firebox.
The damper plate consists of two long lintel pieces and
two short damper plate side pieces.
The two lintels are identical in shape, size and in length,
equal to the width of the MAGNUM fireplace model that
they serve.
Properly placed, one lintel is to sit on top of the firebox
back wall and flush with it; the other lintel sits flush with
the front of the firebox, spanning the firebox opening. These
components both sit on their narrow base so that their bev-
eled face points down and into the firebox interior. (Figure
25)
The damper plate side pieces are designed to sit on the
firebox side wall between the front lintel and the back lintel.
(Figure 14)
Each of the damper plate side pieces is designed specifi-
cally for its own side of the unit. When properly set, each
damper plate side piece fits flush with the outside face of
the firebox sidewall so that its interior bottom edge aligns
with the interior angle of the firebox side wall that it sits on.
(Figure 14)
Be sure to mortar all damper plate components to the
top surfaces of the firebox.
Mortar the contact surfaces of each damper plate side
component where it meets the front and back damper plate
lintel components.
Step 7: With the damper plate assembled and mortared
together, set the cast iron throat damper on top of the damper
plate and over the damper plate opening. The cast iron
damper’s operating plate should face toward the rear of the
fireplace. (Figures 15 & 16)

15 / 60
1”
Front Rear
Rear
Front
End
End
Smoke dome parts
Earthcore
Mortar
Figure 16
Figure 17
Figure 18
Assembly Instructions - Models 36, 42, 48 (cont.)
The flange at all four sides of the cast iron damper
should be supported by the damper plate’s top surface.
Before adjusting the cast iron damper to its final position
proceed to Step 8.
Step 8: Set the back smoke dome component across the
damper plate in a bed of mortar and flush with the back face
of the back damper plate lintel. (Figure 17)
Set the front smoke dome component in mortar across
the damper plate and 2 -1/4 inches back from the front of
the front damper plate lintel. This placement should create a
space of 17 inches between the front and back smoke dome
components.
Position the cast iron damper so that its front flange is
approximately one inch (1") away from the inside face of the
front smoke dome component. (Figure 16)
Run a bead of mortar around the four sides of the cast
iron damper flange to avoid movement of the damper as it
gets opened and closed.
Step 9: Position the smoke dome’s sloping sidewalls at each
end of the smoke dome components. (Figure 17)
The sloping sidewalls fit in between the front and rear
smoke dome components and also fit into the haunches at
the ends of the front and rear smoke dome components.
Mortar all contact surfaces.
Note(s): The smoke dome sloping sidewalls have a beveled
bottom edge so that they will sit tight onto the flat top of the
damper plate.
Step 10: Make sure that all component contact surfaces have
been properly sealed with approved mortar.
Check smoke dome front and back walls to see that they
are plumb, level and in alignment with mating components.
Check alignment of the smoke dome sloping sidewall
components to see that they are fully seated.
Step 11: Set the smoke dome top plate into position on top
of the smoke dome wall assembly. (Figure 18)
One side of the smoke dome top plate shows a thick-
ened center. This side is the bottom face of the top plate.
The fourteen inch (14”) diameter flue hole in the top
plate is centered in the smoke dome from side to side but is
offset from front to back.
Make sure that the top plate is set so that the flue hole
is closer to the back wall of the smoke dome assembly.
Be sure to set the smoke dome top plate flush with
the front, back and sides of the smoke dome assembly. All
contact surfaces must be properly sealed with the approved
mortar.
Note(s):
1. The completed smoke dome assembly should present
a stable and level surface for setting the flue components.
(Figure 18)
See page 39 for “Important Structural Information”.

16 / 60
Assembly Instructions - Model 60
73 ½
32 ”
15 ¾”
15 ¾”
25 ”
Figure 19
Figure 22
Figure 23
Figure 24
The MAGNUM Model 60 is a custom unit made of standard
parts that are cut and fitted together in the field. The fol-
lowing cut and assembly instructions identify the parts by
name and by part number, the quantity required, the field cut
dimensions for each modified component and the placement
of each part in the assembly.
Note(s): At all component placement, be sure to mortar all
contact surfaces with Earthcore Mortar. Check for complete
sealing of each contact joint while assembly progresses (see
“General Isokern Assembly Instructions” on page 12 of this
manual for mortar information and instructions).
Step 1: Base plate, part M61, four required. Two of these
pieces are used “as is” and two require field cutting.
Set two of the un-cut M61 base plate components on
an appropriate masonry foundation and positioned exactly
on the centerline of where the firebox is to sit.
Set the two pieces so that the centerline of the grouping
is a butt joint. The long point of the bevel end of each piece
should be the top face (Figure 19).
Cut the remaining two M61 base plate pieces to fifteen
and seven-eights inches (15-7/8”) in width, measured from
the long point of the bevel end. This cut will be a square
cut.
Set the cut M61 pieces into place against the two un-
cut M61 pieces that are positioned on the centerline of the
fireplace location. Join the bevel end of the cut pieces with
the bevel of the uncut pieces. This makes for square ends at
both the left and right ends of the grouping.
The overall length of the base plate assembly should
measure seventy-three and a half inch (73-1/2”) and twenty-
eight inches (28") deep (Figure 20).
Step 2: Side wall, part M60, eight pieces required, used “as
is”.
The fire box side wall components are used without
modification. The side wall pieces stack four high on both
the left and right hand ends of the base plate arrangement
(Figure 21).
The stack of four fire box side wall components will be
assembled in conjunction with the firebox back wall compo-
nents described in the following steps.
Step 3: Back wall, part M66, four pieces required, to be
“field modified”.
Cut the tongue off one end of each of the four M66 back
wall components. After cutting, each of these four cut pieces
should measure thrity-two and one-eigth inch (32-1/8") from
the cut end to the shoulder of the un-altered end (Figure
22).
Step 4: Back wall, part M66, four pieces required, to be
“field modified”.
Cut one end of each of the four M66 back wall compo-
nents. These four cut pieces should measure twenty-five and
five-eigths inch (25-5/8") from the cut end to the shoulder of
the un-altered end (Figure 23).
Step 5: Build the MAGNUM Model 60 firebox by setting
Figure 21
Figure 20

17 / 60
Assembly Instructions - Model 60 (cont.)
73 ½”
38 ¼”
38 ¼”
4”
Figure 25
Figure 28
Figure 30
a thirty-two and one-eigth inch (32-1/8") M66 back Wall
(from STEP 3) on the base plate with its tongue end inter-
locked into the firebox side wall at the end of the base plate
(Figure 24).
The square cut end of this a thirty-two and one-eigth
inch (32-1/8") M66 back wall component sits flush with the
back of the base plate with its cut end just a couple of inches
past the centerline butt joint in the base plate arrangement
(Figure 25).
Next set the twenty-five and five-eigths inch (25-5/8")
cut M66 piece so that its tongue end interlocks with the side
wall component at the opposite end of the base plate. The
square cut end of the twenty-five and five-eigths inch (25-
5/8") M66 should make a snug butt joint with the square
cut end of the thirty-two and one-eigth inch (32-1/8") M66
component (Figure 25).
Step 6: Continue stacking the remaining three courses of
back wall. Be sure to reverse the positions of the thirty-two
and one-eigth inch (32-1/8") M66 and the twenty-five and
five-eigths inch (25-5/8") M66 in each successive course. In
this way, the butt joint where the two M66 components meet
are staggered from course to course.
The overall width dimension at the back of the firebox
should be seventy-three and a half inch (73-1/2”) (Figure
26).
Step 7: Steel angle four inch by six inch by five-sixteenth
inch (4” x 6” x 5/16”), one each required, seventy three and
a half inch (73-1/2”) long.
A four inch by six inch x five-sixteenth inch (4” x 6”
x 5/16”) steel angle needs to span the top of the MAGNUM
Model 60 firebox opening.
This steel angle sits on top of the uppermost side wall
component with the four inch leg in the horizontal position.
To avoid a thickness problem with the placement of the
steel angle it is necessary to cut a notch in the top Side wall
component where the angle is to sit.
This notch should be cut approximately five-sixteenth
of an inch (5/16") deep. The notch should start at the front
face of the side wall component (at both the left and right
hand walls) and run to a point four inches back toward the
firebox (Figure 27).
The steel angle sits in this notch. The six inch leg of
the steel angle is in the vertical position and is to be located
in alignment with the front of the firebox. The ends of the
steel angle should not protrude beyond the outer firebox side
walls (Figure 28).
Mortar between the steel and the notch in the top of the
side wall is not needed.
Step 8: damper support (front & rear), Part M69, four
required, to be field cut to fit.
Bevel cut one end of each of two M69 damper supports
to thirty-eight and one fourth inch (38-1/4”) in length from
the long point of the bevel cut to the un-cut square end. The
long point of the bevel cut is to be at the top of the damper
Support (Figure 29).
For best results a fifteen degree (15˚) bevel angle is sug-
gested.
Figure 26
Figure 29
Figure 27

18 / 60
Assembly Instructions - Model 60 (cont.)
49 ½”
49½”36”
85½”
Figure 32
Step 9: Bevel cut one end each of two M69 damper sup-
ports to thirty-eight and one fourth inch (38-1/4”) with the
long point of the bevel at the bottom of the damper support.
The bevel angle must be at the same angle – in this case, 15
degrees - to match with the bevel angle of the other damper
supports already cut in Step 8 (Figure 30).
Step 10: Set the cut damper supports along the front and
along the rear of the firebox using one of each of the cut
pieces (one with the long point at the top of the piece and
one with the long point at the bottom of the piece) together
as pairs.
The damper support pair at the front of the firebox
opening will be set into the steel angle from Step 7 (Figure
28).
Since the inside corner of the steel angle is rounded, it is
a good idea to round the bottom front corner of the damper
support to match the steel.
With the bevel cut ends of the damper support pairs
meeting at the middle of the firebox, the bevel joint should
be an even and good fit. The damper supports overall
installed length should be seventy three and a half inch (73-
1/2”).
Note(s): Do not join the damper supports with a butt joint.
The bevel joint discussed above is the REQUIRED type of
joint for the damper support.
The bevel angle of fifteen degrees (15˚) degrees is a
convenient angle and is given as a suggested angle. The
angle of bevel could be greater just so the angles cut in the
adjoining damper supports join.
The angle of the bevel cut could be greater just so the
bevel cut in each damper support joining pair is the same
angle in order to have a good fit at the joint.
Due to the exhaust gas flow restrictions that are caused by
using a standard cast iron poker damper, top seal dampers or
inline chimney dampers must be used with models 60 and
72. When using Isokern DM54 Chimney systems the damp-
ers are installed at the top of the chimney runs. When using
metal flue systems the dampers are installed at the top of the
smoke dome or inline in the chimney system. Please consult
your local sales represtnative for the use of top seal dampers
and metal flue systems for models 60 and 72.
Step 11: damper support (left), part M64L and damper
support (right), part M64R, one each required. To be used
“as is”.
Set the damper support (left) and the damper support
(right) into place on top of the firebox side walls in between
the front and rear damper supports.
Each of the damper supports, right and left, is designed
specifically for its own side of the unit. When properly set,
each damper plate side piece sits flush with the outside face
of the firebox side wall. The interior bottom edge of the
damper support end pieces aligns with the angle of the inte-
rior of the firebox side wall (Figure 32).
For the MAGNUM Model 60 the smoke dome components
stack two tiers high giving a smoke dome of approximately
Figure 34
Figure 33
Figure 31
Figure 35

19 / 60
Assembly Instructions - Model 60 (cont.)
2 ¾”
26”
37 ½”
Figure 36
Figure 38
Figure 40
thirty-two inches (32") in height.
Step 12: smoke dome top big, part 13, two required, to be
“field modified”; smoke dome top medium, part 11, six
required, to be “field modified”; smoke dome top sloping,
part 34, four required, to be used “as is”.
Begin building the MAGNUM Model 60 Fireplace
smoke dome by cutting the haunch off of one end of each
of the two smoke dome top big components, part 13. After
cutting the bottom length of the piece will be forty-nine and
a half inch (49-1/2").
When cutting the haunch off be sure to follow the angle
of the sloping end in order to get the proper slope angle to
the cut (Figure 33).
Step 13: Cut one end of two of the smoke dome top medi-
um, part 11, components at an angle parallel to the opposite
end of the piece. The bottom length of the cut piece should
measure twenty-four inches (24”) (Figure 34).
Step 14: Place one modified smoke dome top big pieces
(haunch cut off and a bottom length of forty-nine and a
half inch (49-1/2") together with one of the smoke dome
top medium pieces that was angle cut to twenty-four inches
(24") bottom length and parallel angle) together on the
damper support and flush with the back wall of the firebox
so that the two smoke dome pieces meet along their field
modified cut line (Figure 35).
The overall length of the two joined smoke dome pieces
should be sevety-three and a half inch (73-1/2").
Step 15: Repeat STEP 14 on the front damper support. Set
the front smoke dome components two and thre fourths inch
(2-3/4") back from the front face of the front damper support
(Figure 36).
Step 16: Fit the top sloping smoke dome component,
part 34, in place between the front and back smoke dome
arrangements at each end of the smoke dome (Figure 37).
Step 17: Continue building the MAGNUM model 60
fireplace smoke dome by cutting two of the smoke dome
medium pieces, part 11, to a bottom length dimension of
thirty-seven and a half inch (37-1/2”). The slope angle of
the cut should match the slope angle of the end being cut
(Figure 38).
Place one of the modified smoke dome top medium
pieces (thirty-seven and a half inch (37-1/2”) bottom length)
on top of and flush with the first tier of smoke dome compo-
nents at the back of the first course of smoke dome.
The haunched, un-cut end of this piece should be flush
with the haunch end of the first tier smoke dome below it
(Figure 39).
Step 18: Repeat this arrangement at the front of the smoke
dome.
Step 19: Cut each of the remaining two smoke dome top
medium pieces, part 11, at an angle cut that is parallel to the
un-cut end and so that its bottom length is twenty-six inches
(26") (Figure 40).
Step 20: Place one of the angle cut smoke dome top
medium pieces at the front and one at the back of the first
tier smoke dome so that they meet the smoke dome top big
(cut to thirty-seven and a half inch (37-1/2”) bottom length)
already set in Steps 17 and 18.
Figure 39
Figure 37