Monessen Hearth ODWR400 Mounting instructions






948
SR cover
11/18/97
For use in U.S./Canada
Underwriter's Laboratories Report No. MH6018
87D1502 3/09 Rev. 1

Homeowner's Installation
and Operating Manual

2
ODWR Series Outdoor Woodburning Fireplaces
87D1502

Description ................................................3
Precautions ................................................3
Moisture Resistance .........................................3
Drafts ....................................................3
Gas Logs .................................................3
Cleaning .................................................3
 ........................................4
Hearth Dimensions ..........................................5
Chase Installation and Parts Identification . . . . . . . . . . . . . . . . . . . . . . . 5
Chimney Requirements ......................................7
 ..............................................8
Moisture Resistance .........................................8
Mounting the Fireplace .......................................8
Planning the Chimney Run ....................................8
The Ten Foot Rule ..........................................8
Chimney Supports ..........................................9
Chase Installation ...........................................9
 ......................................................9
Insulating Fireplace Enclosure for Cold Climates . . . . . . . . . . . . . . . . . . . 9
Framing .................................................10
Chimney Setup ............................................10
Straight-Up Chimney Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Offset Installation ..........................................10
Ceiling Chimney Hole/Possible Obstructions . . . . . . . . . . . . . . . . . . . . . 10
Cutting the Hole ...........................................11
Framing the Ceiling Hole ....................................11
Positioning, Safety Strips, Securing the Fireplace . . . . . . . . . . . . . . . . . 11
Installing Outside Air Kit .....................................12
Installing the Chimney System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Finishing .................................................14
Side Wall Protection ........................................16
Hearth Installation ..........................................16
Installing Line for Gas Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
 ..............................................19
 ...................................................20
 ...........................................21
 .......................................................23






 Read all instructions and warnings carefully before starting installation. Failure to follow these instruc-
tions may result in a possible fire hazard and will void the warranty.
 Fuels used in gas, wood-
burning or oil fired appliances, and the products of
combustion of such fuels, contain chemicals known to
the State of California to cause cancer, birth defects
and other reproductive harm.
California Health & Safety Code Sec. 25249.6

3
ODWR Series Outdoor Woodburning Fireplaces
87D1502





The ODWR fireplaces are clean-faced, solid fuel, wood-
burning fireplaces.

Monessen Fireplaces and component parts have been
highly tested and will operate safely when installed in
accordance with instructions provided in this manual.
Carefully read and understand all instructions 
beginning installation.
If you notice any damage to fireplace or component parts,
immediately report damage to your Monessen Fireplaces
dealer.
Only use MHSC components or the warranty will be
voided and a fire hazard may be created.
MHSC warranty will be voided by and MHSC disclaims
any responsibility for the following actions:
• 

• 



• 
• 






Consult local building codes to ensure that you are in
compliance installing the fireplace.
Fireplaces must be vented to the out-of-doors.

















This outdoor fireplace will shed moderate amounts of
water, but is not waterproof. Water and condensing water
vapor may enter the chase under certain conditions.
The fireplace will not perform as an exterior wall. Mois-
ture penetration must be considered for construction
that places the fireplace in structure walls or on moisture
sensitive surfaces.
When installed on exterior walls: MHSC recommends
the fireplace chase be constructed outside the structure's
weather envelope. Where the platform meets the wall,
use a flashing detail similar to that required for attached
decks. Chase platforms, including hearths should slope
away from the structure at 1/4 in per foot. The fireplace
can be shimmed level.
When installed on surfaces where water may collect or
cause damage: MHSC recommends a slope of 1/8 in
to 1/4 in per foot towards the drain port suggested. The
fireplace can be shimmed level.
Hearths should slope away from the front of the fireplace
and chase at 1/8 in to 1/4 in per foot. Metal safety strips
must be on top of any combustible hearth materials used
for moisture management.

The fireplace should not be located in areas that create
drafts (ie: frequently opened doors and central heating air
inlets/outlets) that hamper the normal flow of air into the
fire.

If you plan to install a gas log, the gas line should be
installed before framing the fireplace. The gas line must
be installed by a certified gas line installer.

There are three methods of cleaning the polished stain-
less steel of your outdoor fireplace;
1. Warm, soapy water - to loosen any dirt film
2. Glass cleaner with ammonia
3. Stainless steel cleaner available at hardware stores
Regardless of which method is used, remember that any-
thing with too much abrasive may dull the finish.

4
ODWR Series Outdoor Woodburning Fireplaces
87D1502
ODWR500 specifications and framing.

42"
(1067 mm)
46"
(1168 mm)
396"
(1006 mm)
5/8"
(16 mm)
5/8" (16 mm)
1/2" (13 mm)
1/2"
226M"
(578 mm)
24"
(610 mm)
76M"
(197 mm)
756O"
(191 mm)
Gas Line
Access
Recessed
Nailing
Flange
FP591
SR42 SPECS
10/28/98
7/6/99 djt
correct dims.
11" Dia.
(279 mm)
Minimum Rough Opening
Width 47" (1194 mm)
Minimum
Rough
Opening
Height
Minimum
Rough
Opening
Depth
50" (1270 mm)
50" (1270 mm)
7056O" (1791 mm)
856M"
(210 mm)
22"
(559 mm)
2256O"
(572 mm)
2656M"
(667 mm)
436M"
(1111 mm)
146"
(372 mm)
11"
(279 mm)
8"
(203 mm)
756O"
(191 mm)
Outside
Air
Gas Line
Access
8" Dia.
(203 mm)
36" (914 mm)

ODWR400 specifications and framing.
36"
(914 mm)
146"
(372 mm)
11"
(279 mm)
40"
(1016 mm)
396"
(1006 mm)
5/8"
(16 mm)
5/8" (16 mm)
4856O" (1232 mm)
4856O" (1232 mm)
1/2" (13 mm)
1/2"
6856O" (1740 mm)
856M"
(210 mm)
22"
(559 mm)
2256O"
(572 mm)
22" (559 mm)
226M"
(578 mm)
24"
(610 mm)
436M"
(1111 mm)
8"
(203 mm)
76M"
(197 mm)
756O"
(191 mm)
756O"
(191 mm)
Outside
Air
Gas Line
Access
Gas Line
Access
Recessed
Nailing
Flange
6811
ODSR36
specs
9/03
11" Dia.
(279 mm)
Minimum Rough Opening
Width 41" (1041 mm)
Minimum
Rough
Opening
Height
Minimum
Rough
Opening
Depth
8" Dia.
(203 mm)
3456O" (876 mm)

5
ODWR Series Outdoor Woodburning Fireplaces
87D1502
A
B
C
FP1531
hearth dimensions
9/04 djt
  
    
ODWR400 31¹⁄₈" 19⁷⁄₈" 15¹⁄₂"
(791 mm) (505 mm) (394 mm)
ODWR500 36³⁄₄" 22⁷⁄₈" 15¹⁄₂"
(934 mm) (581 mm) 394 mm)
FP1531
 Hearth dimensions.
1/2” (13 mm)
FP1642
concrete install
9/06
Blocking
Metal Safety Strips
Hard, Flat Surface
(i.e. concrete)
 Exterior chase installation.
 When installation
is on a hard, flat surface
(such as concrete), the
surface must be sloped
1/4" per foot away from
any structure.
FP1642
FP554
BR/BC
Combo of IWF261 AND IWF265
11/10/97

Insulation methods shown are optional for cold climate, not a
requirement for unit operation or exterior installation .
FP554
 Fireplace and chase parts identification.
Termination Cap
Storm Collar
Pan Flashing
Batt Insulation
(cut out around
firestop)
Firestop
Ceiling Level
Draftstop
Ledge Bracket
Surround
Damper Control
Gas Line
Knockout
(both sides)
Screen
Grate
Firebox
Metal Safety
Strips (1,2 or 3)
Outside Air
Cover Plate
Gas Line Access
(both sides)

FP1641a
exterior chase installation
9/06
Termination Cap
Storm Collar
Pan Flashing
Ledge
Bracket
Surround
Damper
Control
Gas Line
Knockout
(both
sides)
Screen
Grate
Firebox
Metal Safety
Strips (1,2 or 3)
Outside Air
Cover Plate
Gas Line Access
(both sides)
Interior sides
of chase
should be
weather proof
Exterior
Siding
Exterior
Siding


Standoff
FP1641a

6
ODWR Series Outdoor Woodburning Fireplaces
87D1502
FP1001
fireplace setting
1/4/00 djt
10'
(3m)
Min.
6'4"
(1.9m)
Min.
If the fireplace is a
freestanding unit, it must be
located a minimum of 10'
(3 m) from the opening of
the firebox to a combustible
structure.
A minimum height of 6'4"
(1.9 m) measured from the
base of the firebox to the
bottom of the termination
cap is permitted.
FP1001
 Freestanding installation.

7
ODWR Series Outdoor Woodburning Fireplaces
87D1502
0 0 0 0 0 3" 11"
1 0 0 0 0 8¹⁄₄" 20"
0 1 0 0 0 11¹⁄₄" 25¹⁄₄"
2 0 0 0 0 13¹⁄₂" 29¹⁄₄"
1 1 0 0 0 16¹⁄₂" 34¹⁄₄"
0 0 1 0 0 20¹⁄₄" 40³⁄₄"
2 1 0 0 0 21³⁄₄" 43¹⁄₂"
0 0 0 1 0 26¹⁄₄" 51¹⁄₄"
0 1 1 0 0 28¹⁄₂" 55¹⁄₄"
1 0 0 1 0 31¹⁄₂" 60¹⁄₄”
0 1 0 1 0 34¹⁄₂" 65¹⁄₂"
0 0 2 0 0 37¹⁄₂" 70³⁄₄"
1 1 0 1 1 41¹⁄₂" 77³⁄₄"
0 0 1 1 1 45" 83³⁄₄"
0 1 2 0 1 47¹⁄₄" 87¹⁄₂"
0 0 0 2 1 51" 94"
0 1 1 1 1 53¹⁄₄" 98"
0 0 3 0 1 56¹⁄₄" 103¹⁄₄"
0 1 0 2 1 59¹⁄₄" 108¹⁄₂"
0 0 2 1 1 62¹⁄₄" 113¹⁄₂"
0 1 3 0 1 64¹⁄₂" 117¹⁄₂"
0 0 1 2 1 68¹⁄₄" 124"
0 1 2 1 1 70¹⁄₂" 128"
0 0 0 3 1 74¹⁄₄" 134¹⁄₂"
0 1 1 2 2 78" 140³⁄₄"
0 0 3 1 2 81" 146"
0 1 0 3 2 84" 151¹⁄₄"
0 0 2 2 2 87" 156¹⁄₂"
0 1 3 1 2 89¹⁄₄" 160¹⁄₄"
0 0 1 3 2 93" 166³⁄₄"
0 1 2 2 2 95¹⁄₄" 170³⁄₄"
0 0 0 4 2 99¹⁄₄" 177³⁄₄"
0 1 1 3 2 101¹⁄₄" 181³⁄₄"
0 0 3 2 2 104¹⁄₄" 186¹⁄₄"
0 1 0 4 2 107¹⁄₄" 191¹⁄₂"
0 0 2 3 2 110¹⁄₄" 196³⁄₄"
0 1 3 2 3 114" 203¹⁄₄"
0 0 1 4 3 117³⁄₄" 209³⁄₄"
0 1 2 3 3 120" 213¹⁄₂"
0 0 0 5 3 123³⁄₄" 220"


 ¹⁄₂ 
 
 
 G + H cannot exceed 20 feet.
Air Space Clearances: SK8 (2-wall) = 1¹⁄₂" and "S" Series (3-wall) = 2"

The following safety rules apply to offset
installations (letters correspond with il-
lustration above):
 Height of the chimney is measured
from the hearth to the chimney exit.
ODWR400 ODWR500
Maximum: 90'0" 90'0"
Minimum:
Without Elbows 12' 6" 12' 6"
With 2 Elbows* 14' 6" 14' 6"
With 4 Elbows* 21' 0" 21' 0"
 Do not use more than 4 elbows per
chimney.
Attach the straps of the return (top) elbow
to a structural framing member.
The offset (first) elbow of any pair does
not have straps.
IWF269
The chimney cannot be more than 30°
(45° in Canada) from the vertical plane in
any installation*.
The maximum length of the angled run
of the  chimney system is 20 feet. (G
plus H cannot exceed 20 feet.)
 A chimney support (Model SKCS8)
is required every 6 feet of angled run of
chimney. Chimney supports are required
for every 30 feet and 60 feet (SK8 pipe)
or 20 feet and 40 feet (3-wall pipe) of ver-
tical chimney height above the hearth.
Determine the offset distance of your
chimney arrangement from the centerline
of the fireplace to the centerline of the
chimney where it is to pass through the
first ceiling.
 This offset distance may not be
your full offset distance. See Examples 2
and 3.
FP282
MBUF
5/26/96
OFFSET
RISE
FP282
* In Canada, two (2) SK845 are allowed.
 Chimney system requirements.
D
RISE
BG
H
B
OFFSET
C
E
6 FT.
G
H
A
HEARTH
FLOOR
CHIMNEY
SECTION
CHIMNEY FLUE EXIT
ELBOW
FP269
MBUF
5/16/96
rev. 5/25
30˚
OFFSET
ELBOW
30˚
OFFSET
ELBOW
30˚
RETURN
ELBOW
30˚
RETURN
ELBOW
SKCS8
SUPPORT
Example 1 Example 2 Example 3

8
ODWR Series Outdoor Woodburning Fireplaces
87D1502

Preplanning an installation is very important to ensure
safety and to save time and money. An installer must
predetermine where a fireplace will be set and how the
chimney system will be run.

This outdoor fireplace will shed moderate amounts of
water, but is not waterproof. Water and condensing wa-
ter vapor may enter the chase under certain conditions.
The fireplace will not perform as an exterior wall. Mois-
ture penetration must be considered for construction
that places the fireplace in structure walls or on mois-
ture sensitive surfaces.
When installed on exterior walls: MHSC recommends
the fireplace chase be constructed outside the struc-
ture's weather envelope. Where the platform meets
the wall, use a flashing detail similar to that required
for attached decks. Chase platforms, including hearths
should slope away from the structure at 1/4 in per foot.
The fireplace can be shimmed level.
When installed on surfaces where water may collect or
cause damage: MHSC recommends a slope of 1/8 in
to 1/4 in per foot towards the drain port suggested. The
fireplace can be shimmed level.
Hearths should slope away from the front of the fire-
place and chase at 1/8 in to 1/4 in per foot. Metal safety
strips must be on top of any combustible hearth materi-
als used for moisture management.

A fireplace may only be mounted on the following sur-
faces:
1. A flat combustible surface.
2. A raised wooden platform.
3. A concrete block or other solid object placed beneath
each of the four (4) corners of the fireplace.
The fireplace  be spaced 1/2" (13 mm) from a
combustible back wall and 1/2" (13 mm) from a com-
bustible side wall or support. (Page 21, Fig. 21)

Determine how the chimney will be run, length of run
and chimney components required to complete the
job. (Fig. 6)  install a chimney below minimum
heights.
In planning a chimney system, it is important to know:
1. The height of a chimney is measured from the
hearth to the exit point on the termination.
2. A chimney cannot be offset more than 30° from a
vertical plane.
3. A chimney may run straight up or it may be neces-
sary to offset it to avoid obstructions.
4. The maximum length of an angled run (total chimney
system) is 20' (6 m).
5. No more than 2 offsets (4 total 30° elbows in U.S./or
2 total 45° elbows in Canada) per fireplace may be
used.
6. A guy wire stabilizer is required for chimneys extend-
ing more than 6' (1.8 m) above a roof line.

Major U.S. building codes specify a minimum chimney
height above the roof top. The “Ten Foot Rule” is a fire
safety rule and not a draft rule. To ensure proper draft,
it is recommended that you always meet or exceed the
“Ten Foot Rule,” especially when installing a termination
on a high pitch roof. (Fig. 9)
The key points of the "Ten Foot Rule" are:
1. If the horizontal distance from the chimney to the
peak of the roof is 10' (3 m) or less, the top of the
chimney must be at least 2' (610 mm) above the
peak of the roof, but never less than 3' (914 mm)
in height above the highest point where it passes
through the roof.
2. If a horizontal distance from the chimney to the peak
of the roof is more than 10' (3 m), a chimney height
reference point is established on the surface of the
roof a distance of 10' (3 m) from the chimney in a
horizontal plane. The top of the chimney must be
at least 2' (610 mm) above the reference point, but
never less than 3' (614 mm) in height above the high-
est point where it passes through the roof.
L1
L1
LTMODEL SK
2 WALL CHIMNEY
TOTAL
LENGTH
(LT)
INSTALLED
LENGTH
(L1)
SK81
SK818
SK83
SK84
1156O"
1756O"
3556O"
4756O"
1056O"
1656O"
3456O"
4656O"
FP288
MBUF-INSTALLED LENGTH
6/17/96
Installed lengths of chimney sections.
WF288

9
ODWR Series Outdoor Woodburning Fireplaces
87D1502
AC246
 Ten Foot Rule illustration.
2’ Min.
2’ Min.
3’
Min.
0 To 10’
3’
Min.
0 To 10’
AC246
4/1/96
Reference
Point

The chimney system is supported by the fireplace for
vertical chimney heights less than 30' (9 m) above the
hearth. Chimney supports are required if the vertical
height exceeds 30' (9 m) with SK8 chimneys or 20' (6 m)
with 3-wall chimneys. Locate chimney supports at ceil-
ing holes or other structural framing at 30' (9 m) (SK8)
or 20' (6 m) (3-wall) heights. Spacing between chimney
supports  exceed 30' (9 m) (SK8) or 20' (6 m)
(3-wall). Use Chimney Support Model SKCS8. 

 Support provided by elbow straps fulfills the
support requirement only if they are spaced as previ-
ously described. (A chimney support is 2¹⁄₂" (64 mm)
long when installed.)
Angled chimney runs require a support every 6' (1.8 m)
in addition to the elbow straps. Chimney supports are
used for this function. (Fig. 10)

A chase is a vertical boxlike structure which encloses
the fireplace and/or chimney. Chases are typically built
on the outside of the house with fireplace opening cut
into the outer wall of a room. (Page 5, Fig. 5)
If you need help in determining fireplace location or how
the chimney system should be run, contact your Mones-
sen dealer for assistance.
FP284
 Chimney support installation
FP284
MBUF
5/25/96
Chimney Sup-
port Strap
SKCS8


If you live in a cold climate, it is not required but
 that you insulate fireplace
enclosure to eliminate cold air penetration as much
as possible.
Insulate base of fireplace with a noncombustible
insulation rated for a minimum of 300°F. Insulating
is  for outside wall installations over
a concrete slab. If fireplace is installed on a platform,
insulation should be placed on top of the platform
fireplace is set. (Fig. 11)
When a fireplace is installed in a chase or on an
outside wall, enclosure should be treated like any
outside wall in a home. Insulation should be installed
on the inside wall as well as the outside wall(s). In a
chase, it is also a good idea to install a firestop at the
first ceiling level above the fireplace and enclose the
chase with sheeting material. Insulation may then be
installed above sheeting material to assure the space
around the fireplace is totally protected. (Fig. 5)
When installing the chimney,  caulk between
outer pipe and firestop. It is vital that some air be al-
lowed to flow through this very thin gap.


(Page
21, Fig. 21)

FP555
 Insulating between platform and fireplace.
FP555
BR
11/10/97
Hard Flat
Surface
Insulation
Platform

10
ODWR Series Outdoor Woodburning Fireplaces
87D1502

Framing can be constructed before or after the fireplace
is set in place, however, most installers build the frame
before setting the fireplace.
Frame fireplace with 2 x 4 lumber or heavier materials.
Refer to framing dimensions in Figures 1, 2, 3 or 4 for
basic fireplace specifications.
 Framing should be positioned to accommodate
wall covering and fireplace facing material.

Since you have already preplanned the chimney run,
you should know exactly how the installation is to be
accomplished — how much pipe is required, the num-
ber of elbows, if any, and type of termination to be used.
REPORT TO YOUR DEALERS ANY
PARTS DAMAGED IN SHIPMENT, SPECIFICALLY
CHECK THE END CONNECTION OF CHIMNEY SEC-
TIONS AND ELBOWS.
 Fireplaces may use MHSC model SK8, or Mod-
el S (three wall) chimney systems. The ODWR Series
"A" Fireplace will accept the SK8 chimney system as is;
but a TWABR adapter collar is required when using the
Model S (triple wall) chimney system. The installation
procedure described in this manual applies  to the
SK8 system. Either chimney system may be used, but
 be mixed.

To mark the centerline of the flue, put the fireplace in final
position and measure out from the wall: 9¹⁄₄" (235 mm).
Mark a spot on the ceiling directly above the fireplace.
Draw a line parallel to the back wall through this mark.
(Fig. 12)
Using a plumb bob positioned directly over center point
of fireplace flue collar, mark the ceiling to establish the
chimney center point. (Fig. 12)

In order to clear an obstruction, it may be necessary to
offset chimney from vertical. This is accomplished by
using MHSC elbows. Use the 30° Offset Elbow table on
Page 5 to determine proper offset and parts required.
Each offset requires two (2) elbows. The second elbow
is equipped with support straps. It is very important to
install the second elbow in each offset as close to the
ceiling or support as possible so that the elbow straps
can be secured to framing members to help support the
weight of the chimney.
FP556
 Locate centerline of chimney with plumb line.
FP556
BR/BC
LOCATE CENTER LINE
11/10/97
9¹⁄₄"
(235mm)
Chimney Centerline
Actual Centerpoint
Plumb Line
Plumb Bob
Imaginary
Centerpoint
Determine offset distance of your chimney arrangement
from centerline of fireplace to centerline of chimney
where it is to pass through ceiling.
Locate center point of the chimney on ceiling as though
a straight up chimney arrangement is to be used. Mea-
sure your offset dimension from straight up chimney
center point on ceiling.


The size of the hole in ceiling will vary with the angle at
which the chimney passes through ceiling.
Drive a nail up through ceiling at marked chimney cen-
ter point. Go to floor above and see where hole will be
cut. Check to see where existing ceiling joists and other
possible obstructions are located...i.e. wiring, plumbing
etc... If necessary, reposition chimney and/or fireplace
to avoid obstructions.