Monessen Hearth WC400 Mounting instructions






For use in U.S./Canada
Underwriter's Laboratories Report No. MH6018

948
SR cover
11/18/97
948
SC cover
11/18/97
20014528 12/09 Rev. 3
Homeowner's Installation
and Operating Manual

2
WR / WC Series Woodburning Fireplace
20014528


Read all instructions and warnings carefully before starting installation. Failure to
follow these instructions may result in a possible fire hazard and will void the warranty.

The WR/WC Series fireplaces are solid fuel, woodburn-
ing premium fireplaces. The WR400/500 are radiant
clean-face models and the WC400/500 are circulating
models with removable grilles (louvres). Both models are
fully insulated fireplaces.

MHSC fireplaces and component parts have been highly
tested and will operate safely when installed in accor-
dance 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 MHSC 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:
• 

• 

• 
(except for chase
flashings as detailed in Chimney Top installation
instructions).
• 

• 






Consult local building codes to ensure that you are in
compliance installing the fireplace.
Fireplaces must be vented to the out-of-doors.







 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




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  framing the fireplace. The gas line must
be installed by a certified gas line installer.





Safety Information . . . . . . . . . . . . . . . . . . 2
Specifications and Framing . . . . . . . . . . 3
Parts Identification . . . . . . . . . . . . . . . . . 5
Chimney Requirements . . . . . . . . . . . . . 6
Planning Information . . . . . . . . . . . . . . . . 7
Installation .......................8
Replacement Parts . . . . . . . . . . . . . . . . 19
Accessories ..................... 20


3
WR / WC Series Woodburning Fireplace
20014528
5/8" (16mm)
1/2" (13mm)
1/2"
36"
(914mm)
3856M"
(971mm)
40" (1016mm)
5/8"
(16mm)
226M"
(578mm)
16M"
(45mm)
3556O" (902mm)
24"
(610mm)
76M"
(197mm)
756O"
(191mm)
Recessed
Nailing
Flange
FP590
SC36 SPECS
10/28/98
11" Dia.
(279mm)
Rough Opening Width 41"
Rough
Opening
Height
Rough
Opening
Depth
Gas Line
Access
4856O" (1232mm)
4856O" (1232mm)
6856O" (1740mm)
856M"
(210mm)
22"
(559mm)
2256O"
(572mm)
22" (559mm)
436M"
(1111mm)
146"
(372mm)
156"
(391mm)
11"
(279mm)
396"
(1006mm)
3"
(76mm)
8"
(203mm)
756O"
(191mm)
Outside Air
Gas Line
Access
(1041mm)
Electrical Access
8" Dia.
(203mm)
3456O" (876mm)
FP590
WC400 Series specifications and framing.

36"
(914mm)
146"
(372mm)
156"
(391mm)
11"
(279mm)
40"
(1016mm)
396"
(1006mm)
3"
(76mm)
5/8"
(16mm)
5/8" (16mm)
4856O" (1232mm)
4856O" (1232mm)
5/8”(13mm)
1/2"
6856O" (1740mm)
856M"
(210mm)
22"
(559mm)
2256O"
(572mm)
22" (559mm)
226M"
(578mm)
24"
(610mm)
436M"
(1111mm)
8"
(203mm)
76M"
(197mm)
756O"
(191mm)
756O"
(191mm)
Outside
Air
Gas Line
Access
Gas Line
Access
Electrical
Access
Recessed
Nailing
Flange
FP589
SR36 SPECS
10/28/98
7/6/99 djt correct dims.
11" Dia.
(279mm)
Rough Opening Width 41"
Rough
Opening
Height
Rough
Opening
Depth
(1041mm)
8" Dia.
(203mm)
3456O" (876mm)
FP589

WR400 Series specifications and framing.

4
WR / WC Series Woodburning Fireplace
20014528
5/8" (16mm)
1/2" (13mm)
1/2"
42"
(1067mm)
3856M"
(971mm)
46" (1168mm)
5/8"
(16mm)
226M"
(578mm)
16M"
(45mm)
38" (965mm)
24"
(610mm)
76M"
(197mm)
756O"
(191mm)
Recessed
Nailing
Flange
FP592
SC42 SPECS
10/02
11" Dia.
(279mm)
Rough Opening Width 47"
Rough
Opening
Height
Rough
Opening
Depth
Gas Line
Access
50" (270mm)
50" (1270mm)
7056O" (1791mm)
856M"
(210mm)
22"
(559mm)
2256O"
(572mm)
2656M"
(667mm)
436M"
(1111mm)
146"
(372mm)
156"
(391mm)
11"
(279mm)
396"
(1006mm)
3"
(76mm)
8"
(203mm)
756O"
(191mm)
Outside Air
Gas Line
Access
(1194mm)
Electrical Access
8" Dia.
(203mm)
36" (914mm)
FP592
 WC500 Series specifications and framing.

42"
(1067mm)
46"
(1168mm)
396"
(1006mm)
5/8"
(16mm)
5/8" (16mm)
1/2" (13mm)
1/2"
226M"
(578mm)
24"
(610mm)
76M"
(197mm)
756O"
(191mm)
Gas Line
Access
Recessed
Nailing
Flange
FP591
SR42 SPECS
10/28/98
7/6/99 djt
correct dims.
11" Dia.
(279mm)
Rough Opening Width 47"
Rough
Opening
Height
Rough
Opening
Depth
50" (1270mm)
50" (1270mm)
7056O" (1791mm)
856M"
(210mm)
22"
(559mm)
2256O"
(572mm)
2656M"
(667mm)
436M"
(1111mm)
146"
(372mm)
156"
(397mm)
11"
(279mm)
3"
(76mm)
8"
(203mm)
756O"
(191mm)
Outside
Air
Gas Line
Access
Electrical
Access
(1194mm)
8" Dia.
(203mm)
36" (914mm)

 WR500 Series specifications and framing.
FP591

5
WR / WC Series Woodburning Fireplace
20014528

Insulation methods shown are optional
for cold climate, not a requirement for
unit operation.
FP554
 Fireplace and chase parts identification.
FP554
BR/BC
Combo of IWF261 AND IWF265
11/10/97
Termination Cap
Storm Collar
Pan Flashing
Draftstop
Batt Insulation
(cut out around fiestop)
Firestop
Ceiling Level
Nailing Flange
Gas Line Access
(both sides)
Electrical Access
Outside Air Cover Plate Metal Safety Strips
(1, 2 or 3 pieces)
Firebox
Grate
Screen
Gas Line Knockout
(both sides)
Damper Control
Surround
Standoff
A
B
C
FP1531
hearth dimensions
9/04 djt
  
    
WR/WC400 31¹⁄₈" 19⁷⁄₈" 15¹⁄₂"
(791 mm) (505 mm) (394 mm)
WR/WC500 36³⁄₄" 22⁷⁄₈" 15¹⁄₂"
(934 mm) (581 mm) 394 mm)
FP1531
 Hearth dimensions.

6
WR / WC Series Woodburning Fireplace
20014528

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.
WR/WC400 WR/WC500
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
IWF282
* 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

7
WR / WC Series Woodburning Fireplace
20014528
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.

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.

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 14, Fig. 20)


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. 8)
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' (3m) or less, the top of the
chimney must be at least 2' (610mm) above the peak
of the roof, but never less than 3' (914mm) 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' (3m), a chimney height
reference point is established on the surface of the
roof a distance of 10' (3m) from the chimney in a
horizontal plane. The top of the chimney must be
at least 2' (610mm) above the reference point, but
never less than 3' (614mm) in height above the high-
est point where it passes through the roof.
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' (6m).
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' (1.8m) above a roof line.
WF288
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

8
WR / WC Series Woodburning Fireplace
20014528


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 in-
sulation 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. 10)
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 in-
stalled 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. Insu-
lation may then be installed above sheeting material
to assure the space around the fireplace is totally
protected. (Fig. 5)
When installing the chimney,  caulk be-
tween outer pipe and firestop. It is vital that some
air be allowed to flow through this very thin gap.


(Page
14, Fig. 20)


The chimney system is supported by the fireplace for
vertical chimney heights less than 30' (9m) above the
hearth. Chimney supports are required if the vertical
height exceeds 30' (9m) with SK8 chimneys or 20' (6m)
with 3-wall chimneys. Locate chimney supports at ceil-
ing holes or other structural framing at 30' (9m) (SK8)
or 20' (6m) (3-wall) heights. Spacing between chimney
supports  exceed 30' (9m) (SK8) or 20' (6m)
(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" (64mm)
long when installed.)
Angled chimney runs require a support every 6' (1.8m)
in addition to the elbow straps. Chimney supports are
used for this function. (Fig. 9)

A chase is a vertical box like 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 MHSC
dealer for assistance.
FP284
 Chimney support installation
FP284
MBUF
5/25/96
Chimney Sup-
port Strap
SKCS8

9
WR / WC Series Woodburning Fireplace
20014528

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.


If a circulating fireplace is to be installed, run the 120
VAC, 60 Hz wiring to the left side of installation. Wiring
must be completed  the fireplace is secured and
finish material applied.
Remove the cover plate and electrical knockout on the
lower left side of the fireplace and set aside. Follow the
instructions on Page 10 for proper wiring and installation
of the EB1.
If the fan kit is not being installed with the fireplace, it
is highly recommended that 120 VAC supply be made
available since someone may elect to install a blower at
a later date.


• Wiring should be installed by a certified
electrician.
• Turn off circuit breaker before wiring models.
Once fireplace is secured, complete wiring the fan
kit. Remove knockout in the center of the back of
the EB1 and install listed cable clamps. Feed electri-
cal wire through listed cable clamp leaving approxi-
mately six (6) inches of wire exposed through the
EB1. Secure listed cable clamp to the wire.
Attach white wire from power source to one (1) wire
of receptacle and secure with nut. Attach black
wire from power source to the other wire of recep-
tacle and secure with nut. Be sure nuts are secured
tightly.
Secure EB1 assembly to inside of electrical box
coverplate using two screws. Attach cover to face of
the EB1 while being careful to position excess wire
completely within the EB1, then attach coverplate to
fireplace.

Refer to optional Model FK12 fan kit assembly in-
stallation instructions for field installation.

Since you have already preplanned the chimney run,
you should know exactly how the installation is to be ac-
complished — how much pipe is required, the number
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 WR/WC 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.
FP555
 Insulating between platform and fireplace.
FP555
BR
11/10/97
Hard Flat
Surface
Insulation
Platform

10
WR / WC Series Woodburning Fireplace
20014528

To mark the centerline of the flue, put the fireplace
in final position and measure out from the wall: 9¹⁄₄"
(235mm). Mark a spot on the ceiling directly above the
fireplace. Draw a line parallel to the back wall through
this mark. (Fig. 11)
Using a plumb bob positioned directly over center point
of fireplace flue collar, mark the ceiling to establish the
chimney center point. (Fig. 11)

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 6 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.
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.

Cover fireplace collar opening and cut proper sized
chimney hole in chimney. The SK8 pipe allows you to
run pipe through a typical 16” on center joist without
cutting joists.

Frame the ceiling chimney hole as shown in Figure
12. It is good practice to use framing lumber that is the
same size as the ceiling joists; this is a requirement at
attic level.
FP556
 Locate centerline of chimney with plumb line.
FP556
BR/BC
LOCATE CENTER LINE
11/10/97
956M"
(235mm)
Chimney Centerline
Actual Centerpoint
Plumb Line
Plumb Bob
Imaginary Cen-
terpoint
 Typical frame for ceiling chimney hole.
FP551
FP551
BR/BC
9/29/97
AB AB
A "SK" Series framing = 1456O" X 1456O" (368 x 368mm)
B"S" Series framing = 1756O" X 1756O" (445 x 445mm)
Existing
Ceiling Joist
Ceiling
New
Framing Members
Chimney Hole