Monessen Hearth CWC400 Mounting instructions
For use in U.S./Canada
Underwriter's Laboratories
Report No. MH7603
87D1504 12/09 Rev. 4
FP583A
WMC
12/18/98
Homeowner's Installation
and Operating Manual
2
CWC Series Woodburning Fireplace
87D1504
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 CWC Series fireplaces are solid fuel, woodburning
premium fireplaces. The CWC are circulating models
with removable grilles (louvers).
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. Careful-
ly 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 the Chimney Top installa-
tion 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, woodburn-
ing or oil fired appliances, and the products of combus-
tion of such fuels, contain chemicals known to the State
Safety Information . . . . . . . . . . . . . . . . . . 2
Specifications and Framing . . . . . . . . . . 3
Parts Identification . . . . . . . . . . . . . . . . . 4
Chimney Requirements . . . . . . . . . . . . . 5
Planning Information . . . . . . . . . . . . . . . . 6
Installation ....................... 7
Replacement Parts . . . . . . . . . . . . . . . . 18
Accessories ...................... 19
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 in-
stalled framing the fireplace. The gas line must be
installed by a certified gas line installer.
3
CWC Series Woodburning Fireplace
87D1504
50" (1270mm)
42"
(1067mm)
35Z\v" (895mm)
46" (1168mm)
B\,"
(16mm)
B\," (16mm)
Z\x" (13mm)
Z\x"
19C\v" (502mm)
1C\v"
(45mm)
38" (965mm)
21"
(533mm)
7C\v"
(197mm)
7Z\x"
(191mm)
Recessed
Nailing Flange
FP592A
WMC42 SPECS
1/28/99
13C\," Dia.
(340mm)
Rough Opening Width 47"
Rough
Opening
Height
Rough
Opening
Depth
Gas Line
Access
50" (1270mm)
70Z\x" (1791mm)
8Z\v"
(210mm)
22"
(559mm)
22Z\x"
(572mm)
26Z\v"
(667mm)
40C\v"
(1035mm)
14B\,"
(372mm)
15C\,"
(391mm)
9Z\x"
(241mm)
36B\,"
(930mm)
3"
(76mm)
8"
(203mm)
7Z\x"
(191mm)
Outside Air
Electrical
Access
11" Dia.
(279mm)
(1194mm)
Gas Line Access
8" Dia.
(203mm)
36" (914mm)
CWC500 Series specifications and framing.
FP592A
FP590A
WMC36 SPECS
1/28/99 djt
B\," (16mm)
Z\x" (13mm)
Z\x"
36"
(914mm)
35Z\v" (895mm)
40" (1016mm)
B\,"
(16mm)
19 C\v" (502mm)
1C\v"
(45mm)
35Z\x" (902mm)
21"
7C\v"
(197mm)
7Z\x"
(191mm)
Recessed
Nailing Flange
11" Dia.
(279mm)
Rough Opening Width 41"
Rough
Opening
Height
Rough
Opening
Depth
Gas Line
Access
47" (1194mm)
47" (1194mm)
66Z\v" (1683mm)
8Z\v"
(210mm)
22"
(559mm)
22Z\x"
(572mm)
22" (559mm)
40C\v"
(1035mm)
14B\,"
(372mm)
15C\,"
(391mm)
9Z\x"
(241mm)
36B\,"
(930mm)
3"
(76mm)
8"
(203mm)
7Z\x"
(191mm)
Outside Air
Gas Line Access
Electrical
Access
8" Dia.
(203mm)
33C\v" (857mm)
(1041mm)
FP590A
CWC400 Series specifications and framing.
4
CWC Series Woodburning Fireplace
87D1504
Insulation methods shown are optional
for cold climate, not a requirement for
unit operation.
FPC554
Fireplace and chase parts identification.
Termination Cap
Storm Collar
Pan Flashing
Draftstop
Top Shield
Surround
Outlet Grille
Damper
Control
Gas Line Knockout
(both sides)
Screen
Grate
Firebox
Metal Safety Strips
(1, 2 or 3 pieces)
Inlet Grille
Outside Air
Cover Plate
Electrical Access
Gas Line Access
(both sides)
Nailing Flange
Standoff
Batt Insulation
(cut out around firestop)
Firestop
Ceiling Level
A
B
C
FP1531
hearth dimensions
9/04 djt
CWC400 33Z\x" 20Z\v" 18Z\v"
(851 mm) (514 mm) (464 mm)
CWC500 39B\," 23C\," 18Z\v"
(1007 mm) (594 mm) (464 mm)
FP1531
Hearth dimensions.
5
CWC Series Woodburning Fireplace
87D1504
D
RISE
BG
H
B
OFFSET
C
E
6 FT.
G
H
A
HEARTH
FLOOR
CHIMNEY
SECTION
CHIMNEY FLUE EXIT
ELBOW
FPC269
Chimney Requirements -typ. offset
Circulating models
1/28/99 djt
30˚
OFFSET
ELBOW
30˚
OFFSET
ELBOW
30˚
RETURN
ELBOW
30˚
RETURN
ELBOW
SKCS8
SUPPORT
Example 1 Example 2 Example 3
¹⁄₂
The following safety rules apply to
offset installations (letters correspond
with illustration above):
Height of the chimney is measured
from the hearth to the chimney exit.
CWC400 CWC500
Maximum: 90' 90'
Minimum:
Without Elbows 12' 6" 12' 6"
With 2 Elbows* 15' 0" 15' 0"
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.
FPC269
IWF282
MBUF
5/26/96
OFFSET
RISE
IWF282
* In Canada, two (2) SK845 are allowed.
Chimney system requirements.
0 0 0 0 0 3" 11"
1 0 0 0 0 8Z\v" 20"
0 1 0 0 0 11Z\v" 25Z\v"
2 0 0 0 0 13Z\x" 29Z\v"
1 1 0 0 0 16Z\x" 34Z\v"
0 0 1 0 0 20Z\v" 40C\v"
2 1 0 0 0 21C\v" 43Z\x"
0 0 0 1 0 26Z\v" 51Z\v"
0 1 1 0 0 28Z\x" 55Z\v"
1 0 0 1 0 31Z\x" 60Z\v”
0 1 0 1 0 34Z\x" 65Z\x"
0 0 2 0 0 37Z\x" 70C\v"
1 1 0 1 1 41Z\x" 77C\v"
0 0 1 1 1 45" 83C\v"
0 1 2 0 1 47Z\v" 87Z\x"
0 0 0 2 1 51" 94"
0 1 1 1 1 53Z\v" 98"
0 0 3 0 1 56Z\v" 103Z\v"
0 1 0 2 1 59Z\v" 108Z\x"
0 0 2 1 1 62Z\v" 113Z\x"
0 1 3 0 1 64Z\x" 117Z\x"
0 0 1 2 1 68Z\v" 124"
0 1 2 1 1 70Z\x" 128"
0 0 0 3 1 74Z\v" 134Z\x"
0 1 1 2 2 78" 140C\v"
0 0 3 1 2 81" 146"
0 1 0 3 2 84" 151Z\v"
0 0 2 2 2 87" 156Z\x"
0 1 3 1 2 89Z\v" 160Z\v"
0 0 1 3 2 93" 166C\v"
0 1 2 2 2 95Z\v" 170C\v"
0 0 0 4 2 99Z\v" 177C\v"
0 1 1 3 2 101Z\v" 181C\v"
0 0 3 2 2 104Z\v" 186Z\v"
0 1 0 4 2 107Z\v" 191Z\x"
0 0 2 3 2 110Z\v" 196C\v"
0 1 3 2 3 114" 203Z\v"
0 0 1 4 3 117C\v" 209C\v"
0 1 2 3 3 120" 213Z\x"
0 0 0 5 3 123C\v" 220"
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,
TCS8A - 8 inch triple wall) 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 vertical chim-
ney 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.
G + H cannot exceed 20 feet.
Air Space Clearances: SK8 (2-wall) = 1Z\x" and "S" Series (3-wall) = 2"
6
CWC Series Woodburning Fireplace
87D1504
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 be mounted on the following surfaces:
1. A flat combustible surface.
2. A raised wooden platform.
3. A concrete block or other solid object placed be-
neath 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. Refer to Page 14, Figure
18.
Determine how the chimney will be run, length of run
and chimney components required to complete the
job. (Fig. 4) install a chimney below minimum
heights.
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. It is recommended that
you always meet or exceed the “Ten Foot Rule,” espe-
cially when installing a termination on a high pitch roof.
(Fig. 6)
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' (609 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 that is 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' (609 mm) above the reference point, but never
less than 3' (914 mm) in height above the highest
point where it passes through the roof.
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 chim-
ney 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 (not provided) is required for
chimneys extending more than 6' (1.8 m) above a
roof line.
L1
L1
LTMODEL SK
2 WALL
CHIMNEY
TOTAL
LENGTH
(LT)
INSTALLED
LENGTH
(L1)
SK81
SK818
SK83
SK84
56O
"
56O
"
56O
"
56O
"
56O
"
56O
"
56O
"
56O
"
FP288A
MBUF-INSTALLED LENGTH
Triple wall
1/28/99 djt
TRIPLE
WALL
81
818
83
84
FP288A
Installed lengths of chimney sections.
2’ Min.
2’ Min.
3’
Min.
0 To 10’
3’
Min.
0 To 10’
AC246
4/1/96
Reference
Point
AC246
Ten Foot Rule illustration.
7
CWC Series Woodburning Fireplace
87D1504
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 ceiling 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 (SK8) and TCS8A (3-wall).
Support provided by elbow straps ful-
fills the support requirement only if they are spaced as
previously described. (A chimney support is 2Z\x" 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. 7)
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. 3)
If you need help in determining fireplace location or
how the chimney system should be run, contact your
MHSC dealer for assistance.
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. 8)
When a fireplace is installed in a chase or on a
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. 3)
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.
WHEN INSTALLING A FIREPLACE IN
AN INSULATED ENCLOSURE, BE SURE ALL RE-
QUIRED AIR SPACES ARE MAINTAINED. (Page 13,
Fig. 18)
FP284
Chimney support installation.
FP284
MBUF CHIMNEY SUPPORT
1/28/99 djt
Chimney Sup-
port Strap
Chimney
Support
FPC555
Platform insulation
circulating model
1/28/99 djt
FPC555
Insulating between platform and fireplace.
Cover Plate
Top Shield
Hard, Flat
Surface
Insulation
Platform
8
CWC Series Woodburning Fireplace
87D1504
Framing can be constructed before or after the fire-
place 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 and 2 for
basic fireplace specifications.
Framing should be positioned to accommo-
date wall covering and fireplace facing material.
To prevent electrical shock, the house
power must be disabled. This can be accomplished by
positioning the circuit breaker to off.
The fan kit assembly and model EB1 junction box are
factory installed.
Check local building codes to determine if a
junction box is required at the romex pigtail/house wire
connection.
The SCVS Variable Speed Control is tested and safe
when installed in accordance with these instructions.
Read all instructions before beginning installation. Fol-
low instructions carefully.
The SCVS speed control may be used as an alternate
wall switch in lieu of the single pole (Listed 1.5 Amp
120V) switch described in the fan or fireplace installa-
tion instructions.
For mounting the speed control, a 2" deep standard
electrical box should be used. Using wire nuts sup-
plied with the speed control, connect control in series
with fan motors and line voltage. Refer to Figure 9 for
wiring diagram.
Mount speed control in electrical box and attach wall
plate with screws provided. Push on knob so that indi-
cator is in OFF position. (Fig. 10)
Turn control knob counterclockwise until a click is
heard for OFF position. To operate fans, turn knob
clockwise and adjust fan speed as desired.
Green
White
Black
White
FP1212
SCVS wiring
5/23/02 djt
Ground
Ground Screw
Variable Speed Con-
trol (optional)
Wire Nuts
(supplied)
Receptacle
Fireplace
Junction Box
Ground
Stud
Wall
Junction Box
(not supplied)
Black
FP1212
SCVS wiring diagram.
OFF
LOW
FP1213
SCVS
components
5/24/02 djt
Electrical Box
(not supplied)
Speed Con-
trol Cover
Plate
Oval
Head
Screw
Plastic
Knob
Flat
Head
Screw
Wire Nut FP1213
Speed control mounting.
9
CWC Series Woodburning Fireplace
87D1504
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 number
of elbows, if any, and type of termination to be used.
REPORT TO YOUR DEALER ANY PARTS
DAMAGED IN SHIPMENT, SPECIFICALLY CHECK
THE END CONNECTION OF CHIMNEY SECTIONS
AND ELBOWS.
The CWC400 may use MHSC model SK8,
or Model S (three wall) chimney systems. However,
a TWABR adapter collar is required when using the
Model S (triple wall) chimney system on this unit. The
CWC500 is designed to use only the "S" triple wall
chimney system. Either chimney system may be used,
but be mixed.
To use the TWABR adapter on the CWC400,
remove and discard the cover plate on the top shield.
(Fig. 8)
To mark the centerline of the flue, put the fireplace in
final position and measure out from the wall: 9Z\v" (235
mm). 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 estab-
lish 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 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 the elbow
straps can be secured to framing members to help
support the weight of the chimney.
Determine offset distance of your chimney arrange-
ment from centerline of fireplace to centerline of chim-
ney 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. Measure 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 center
point. Go to floor above and see where hole will be cut.
Check to see where existing ceiling joists and other pos-
sible 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 cut-
ting joists.
FPC556
WMC
LOCATE CENTER LINE
Circulating model
1/28/99 djt
9Z\v"
(235mm)
FPC556
Locate centerline of chimney with plumb line.
Chimney Centerline
Actual Centerpoint
Plumb Line
Plumb Bob
Imaginary Cen-
terpoint
10
CWC Series Woodburning Fireplace
87D1504
Frame the ceiling chimney hole as shown in Figure 13.
It is good practice to use framing lumber that is the
same size as the ceiling joists; this is a requirement at
attic level.
The following table gives firestop spacer model num-
bers:
Safety strips are used to ensure that any combustible
materials in front of the fireplace are protected even
though a noncombustible hearth extension is required.
If fireplace is to be elevated above the floor, a “Z”
shaped metal safety strip must be fabricated and used
to protect combustible surfaces in front of the fireplace.
This “Z” shaped safety strip is not provided but must be
fabricated of metal with each horizontal leg at least 1Z\x"
(38 mm) wide and equal in length to the metal strips
provided with the fireplace.
Safety strips are not required over noncombus-
tible floors where all supports at the base of the fireplace
are noncombustible.
Nailing flanges are integrated on the face of the fire-
place. To level the box and secure it firmly in place, bend
the nailing flanges and install as shown in Figure 15.
Typical frame for ceiling chimney hole.
FP551
WF551
BR/BC
9/29/97
See
Fig. 12
See
Fig. 12
Existing
Ceiling
Joists
Ceiling
New Framing
Members
Chimney
Hole
Ceiling chimney hole sizes necessary for installing
firestop spacer.
8" Flue SKFS2A SKFS6A
"SK" Series 14Z\x" x 14Z\x" 14Z\x" x 25Z\x"
(368mm x 368mm) (368mm x 648mm)
8" Flue FS2A FS6A
"S" Series 3-Wall 17Z\x" x 17Z\x" 17⁷\," x 29B\,"
(445mm x 445mm) (454mm x 753mm)
The inside dimension of the frame must be the same
as the hole size selected from Figure 13 in order
to provide required air space between the outside
diameter of the chimney and the edges of the framed
ceiling hole. (1Z\x" - SK8; 2" - 3 wall)
Slide fireplace into position.
Lift the fireplace front slightly and slide the metal safety
strips under front bottom edge about 1Z\x" (38 mm),
allowing the remainder to extend in front of firebox.
Overlap strips at least 1/2" (13 mm) to provide a posi-
tive joint. (Flat safety strips are packed with fireplace.)
(Fig. 14)
FPC557
Safety strip installation.
FPC557
WMC Safety strip installation
circulatin models
1/29/99 djt
Metal Safety
Strips
(1, 2 or 3 Pieces)
Z\x" (13mm)
Min. Overlap
1Z\x"
(38mm)
"Z"
Safety
Strip
Fire-
Place
Plat-
Form Hearth Ext.
(not supplied)
FPC549
Fasten fireplace in position.
FPC549
Nail flange/standoff
circulating models
1/29/99 djt
Nail Top
Standoffs
Nail Side-
Nailing
Flanges
11
CWC Series Woodburning Fireplace
87D1504
An outside air kit is installed in all CWC Series Fire-
places. If desired, or if local codes mandate the use of
an air kit, then an AK-MST is required to complete the
installation (from air kit to the outdoors). If the outside
air kit is to be used, the AK-MST be installed
the fireplace is enclosed. Refer to the AK-
MST instructions for field installation. The outside air
control lever is located at the front edge of the left side
brick. To ‘open’, push the control lever down toward
the hearth brick. To ‘close’, pull the control lever up
and over. (Fig. 16)
FPC558
Install pipe, listening for the snap-lock to fasten.
UP
FPC558
WMC
Pipe install
Circulating models
1/29/99 djt
Inner Pipe Section
Pipe
Rim
Pipe
Rim
Hem
Lance
FP270/271
CR Series
2/19/99 djt
Attach straps to a structural framing member.
FP270/271
Support Structure
Elbow Strap
(Must be tight)
Ceiling
Hole
Framing
Angle Firestop
Chimney Support Strap
(Must be tight)
CLOSED
OPEN
WF 710
OUTSIDE AIR LEVER
WOOD FIREPLACES
5/28/98
FP710
Outside air operation.
Start by attaching the first chimney section to the collar
on top of the fireplace.
Install the pipe as pictured in Figure 17. When you
get a good lock, you will hear the pipe clearly snap
together. Once sections are snap-locked in place, it is
extremely difficult to get them apart.
When installing elbows, only outer pipe will snap- lock.
Middle pipes simply slide into position. Be sure to
always attach straps on upper elbow to a structural
framing member. (Fig. 18)
Continue installing the pipe as required until pipe is
installed up through the ceiling. At this point, you must
install a firestop spacer.
A firestop spacer is used to keep pipe spaced properly
and required for safety.
Nail the firestop spacer (at each corner) to the framing
members of the ceiling hole. A firestop spacer
is not required at the roof.
Hole sizes listed in Figure 13 for angled firestop spacers
provide minimum required air space to chimney pipe for
ceiling thickness up to 8" (203 mm). When combined
thickness of ceiling material, ceiling joists and flooring
material exceeds 8" (203 mm), adjustments must be
made in framing to assure that minimum air spaces to
chimney are maintained.
Figure 19 shows different installation procedures for
both an area that is an attic and an area that is not an
attic.
If the area above the ceilingan attic, position the
firestop spacer with the flange on the ceiling side and the
angled portion extending up into the hole.
If the area above the ceiling an attic, position the
firestop spacer with the flange on the top of the framed
12
CWC Series Woodburning Fireplace
87D1504
FP593
SR/C
11/20/97
Installing firestop spacer.
FP593
Nails (4)
Firestop Spacer
Joist
Joist
Firestop Spacer
Nails (4)
FP263
Attic shield installlation (Canadian requirement).
IGF263
MBUF
5/9/96
Attic Insula-
tion Shield
Ceiling
Base
Flanges
Nails
(4 required)
Attic Joist
hole and the angled portion extending down into the
hole.
Firestop spacers are not available for nor are they re-
quired on vertical walls.
put any sealant around the area where the
outer pipe slides through the firestop spacer. If you seal
this area,
In Canada, an attic insulation shield is required to
prevent attic insulation from contacting the chimney
section. If the attic insulation shield is used, the
firestop is not required in the attic installation. Framing
dimensions for the chimney hole should measure 14Z\x"
x 14Z\x" (368 x 368 mm) for SK8; 17Z\x" x 17Z\x" (445 x
445 mm) for 3-wall. An attic shield MUST be installed
on top of attic joists (above the floor level). (Fig. 20)
In the U.S., it is a good idea, although not al-
ways required, to install an attic insulation shield where
blown-in insulation is planned to be used in the attic.
Install the attic insulation shield with the flanges on its
base extending down into the framing hole. Nail each
corner of attic insulation shield to the framing members
of the ceiling hole using 8d nails. Attic shields are not
required at the roof.
Continue attaching pipe sections to complete system
to next level always being careful that the pipe is firmly
snapped locked in place before proceeding to next pipe
section.
If chimney supports are required, they are installed
the same as elbows. Nail chimney support straps to
adjacent structural framing, as shown on Page 7, Figure
7. Bend straps as necessary and make sure they are
secure so they will support the weight of the chimney. A
chimney support is 2Z\x" long when installed. Consider
this dimension when determining how many straight
chimney sections are needed.
Chimney supports are generally used in long
runs in a chase installation.
If you encounter additional ceilings, repeat same steps
required for first ceiling installation. Refer to firestop
illustration on Figure 19.
Run pipe to roof line. Since chimney system must be
vented to the out-of-doors, you use an approved
termination.
If a chase is used, refer to the installation manual pro-
vided with the termination cap.
Use same procedure detailed in locating center point of
the flue system.
Drive a nail up through roof at the center point. This will
determine center point on outside of the roof.
If the attic insulation shield is used, the firestop is not
required in the attic installation.
13
CWC Series Woodburning Fireplace
87D1504
Size of roof hole varies with the type of chimney ter-
mination installed. Refer to installation instructions
provided with the chimney termination to find correct
size of roof hole.
There must be an air space (1Z\x" - SK8; 2" - 3-wall)
between outermost portion of chimney sections and any
adjacent combustible surfaces. (Combustible surfaces
include burnable materials such as: ceiling members,
joists, flooring, combustible insulation and roof struc-
tures.)
Mark an outline of the roof hole around the center of the
point nail. Hole dimensions given in the chim-
ney top installation instructions are dimen-
sions; therefore, the hole size must be marked on the
roof accordingly.
Cover the opening of the installed chimney so debris
cannot get into the system.
Cut and frame the hole. It is good practice to use fram-
ing lumber that is the same size as the rafters. Install
the frame securely because the chimney top and flash-
ing anchored to the frame must be able to withstand
heavy winds.
Since you have already preplanned the height of your
termination according to the Ten Foot Rule, continue to
install pipe to the predetermined height.
Check the chimney top installation instructions for
details on how high above the roof top the chimney sec-
tions (all pipes) should extend.
Follow the installation instructions provided with the
chimney termination you have selected.
Refer to Page 4, Figure 3 for an illustration of a typical
chase installation.
All joints between the finished wall and
the fireplace surround (top/sides) must be sealed with
noncombustible material to prevent cold air leakage into
the room. Only noncombustible material may be applied
to the facing of the fireplace surround. (Black painted
area) (Fig. 21)
Finish the wall with material of your choice.
(Fig. 23)If a combustible material is
Only noncombustible
material may be applied
as facing to the black
fireplace surround.
Wall
Shield
Hearth
Extension
0" Clearance
to Floor
Firestop
Z\x" Air
Space
to Back
Z\x" Air
Space
to Sides
FPC559
WMC
AIR SPACES
circulating models
1/29/99 djt
Front View Side View
Standoff
Combustible framing material MUST NOT
penetrate AIR SPACE (shaded areas).
Air Space Clearances
Z\x" Air Space
To Sides
1Z\x" (SK8)
2" (3-wall)
Minimum clearances to combustibles.
FPC559
14
CWC Series Woodburning Fireplace
87D1504
used below a flat mantel shelf, consult your local building
codes for minimum clearance from top of fireplace open-
ing to bottom of mantel shelf.
All joints (top, bottom and sides) where wall or deco-
rative facing material meets fireplace surround must
be completely sealed with a noncombustible material.
(Figs. 22 and 23)
No side wall protection is required for fireplaces
installed at 45° to two (2) side walls (corner installation).
Often a decorative surround or vertical portion of the
mantel is desired. If this is constructed of any combus-
tible material it must be within the safe zone indicated in
Figure 23.
Adjacent combustible side walls that are within the mini-
mum dimensions shown in Figure 24 of fireplace open-
ing must be protected with MHSC Wall Shield Model
SP40 or a specifically built wall shield described below.
The special wall shield design described in Figure 19 is
an alternate method of adding protection to side walls
and can be used in place of the SP40 with the same
wall clearances specified for the SP40. Rt must =1.85
minimum.
FP531b
Mantel clearance.
FP531b
mantel clearances
9/03 djt
Z\x"
12"
(305mm)
Max.
12" (305mm)
Min.
1Z\x"
(38mm)
6"
(159mm)
Min.
Combustible
Mantel and
Trim Finished Wall
Header
Standoff
Noncombustible
Material
Grille
Opening
Fireplace
Opening
2 x 4 Stud
Finished Wall
Must be sealed with non-
combustible material
Fireplace Front
MA81
Combustible mantel clearances.
MA81
rev. 8/5/97
1Z\x"
Ref.
Combustible materials are
permitted within a shaded area
shown in Figure 23 titled
Minimum Wall Clearances.
*
**
Face Plate
15
CWC Series Woodburning Fireplace
87D1504
1. Manville - CERAFORM 126, K=.27,
1/2 inches thick
2. MHSC - EH2416, K = .458,
1 inch thick required.
A hearth extension is required to protect a combustible
floor in front of the fireplace. Refer to Figure 24 for
minimum dimensions and mounting detail.
The hearth extension described in Figure 24 must be a
durable noncombustible material with a minimum (to-
tal) Rt value of 1.09; refer to Figure 25 for examples.
The overall height (above a combustible floor), depth
and width must be as indicated, with the extension
centered to the fireplace opening.
The top of insulation must be covered with a noncom-
bustible decorative covering a piece of .018” mini-
mum sheet metal, to protect hearth extension material.
(Fig. 24)
Secure the hearth extension to the floor to prevent shift-
ing, using trim molding or other similar means at three
(3) outer edges. Seal crack between the fireplace hearth
and hearth extension with a noncombustible material.
(Figs. 22 and 26)
Alternate noncombustible materials may be used provid-
ing the (total) thermal resistance (Rt value) of the alter-
nate material employed is greater than or equal to R =
1.09. Thermal resistance (R) or thermal conductivity (K),
may be obtained from manufacturer of the material. Fac-
tors are related by the formula K = 1/R.
T = given thickness
R = thermal resistance for a given thickness (T)
K = thermal conductivity
Noncombustible material with a lower R value may
be used, provided thickness of material is sufficiently
greater to maintain an equivalent (total) thermal resis-
tance (Rt).
Minimum Wall Clearances
WITH
Noncombustible
Surround Facing
WITHOUT
Noncombustible
Surround Facing
Minimum Hearth Extension Dimensions
(for On-Site Construction)
G
HG
J
Seal cracks
between the
fireplace
and hearth
extension with
noncombustible
material
Safety strips
must overlap
56O" minimum
May install
noncombustible
decorative
covering
OR .018" min.
sheet metal FIREPLACE
HEARTH
COMBUSTIBLE
FLOOR
MINIMUM
INSULATION
VALUE "R"
4" MIN.
FP594A
WMC combustible min.
1/29/99 djt
FIREBOX
OPENING
A - Min. clearance
to combustible
perpendicular wall
B - Min. clearance
to combustible
perpendicular wall when
using noncombustible wall shield*
SIDE
WALL SIDE
WALL
F**
C**
E
E
D
4" BRICK
(Example material)
Combustible material permitted within shaded area.
* Noncombustible wall shield requires 1" MHSC EH2416
insulation (minimum R Value = 1.85) between decorative
noncombustible rigid covering and combustible wall.
Minimum height and width is 40" x 40".
** Dimension/degree of angle will vary depending on thickness
of noncombustible surround facing.
4"
Shaded area starts
1/2" away from
edge of unit
FP594A
Combustible side wall protection and hearth extension dimensions.
CWC400 16" 12" 48° 41° 18" 14" 7C\v" 16" 48"
406 mm 305 mm 457 mm 356 mm 197 mm 406 mm 1219 mm
CWC500 20" 12" 42° 35° 18" 14" 11Z\x" 20" 61Z\x"
508 mm 305 mm 457 mm 356 mm 292 mm 508 mm 1562 mm
16
CWC Series Woodburning Fireplace
87D1504
COMMON MATERIALS AND FACTORS
MATERIAL K* RMINIMUM
THICKNESS
EH2416
Common Brick
0.458
5.0
1.09 0.50 in.**
0.10 5.46 in.**
(MHSC)
R Value is for 1/2 inch.
* Units of K = BTU/SQ FT/HR/˚F/IN
** Thickness of Listed Material
FP533ADD
Addendum
6/1/99 djt
8/4/99 changed .2 to .1
one inch to 1/2 inch djt
Hearth extension material factors.
FP533ADD
NEW K of new material (per inch) thickness
required = ------------------------------------ X of listed
thickness K of listed material (per inch) material
To determine the thickness required for any mate-
rial:
T (new) = 5.0 / 0.458 x 0.50 in. = (new re-
quired thickness).
FP550
BR/BC - SEALING
DETAILS
9/29/97
Wall Covering
Noncombustible
Decorative
Facing
Noncombustible
Decorative
Covering
Seal all cracks
between fireplace
surround and wall
materials with
noncombustible
material.
Seal crack
between fireplace
and hearth extension
with noncombustible
material.
2x4" Header -
Do not notch at
standoffs.
Safety Strips -
Must be overlapped
Z\x" minimum.
Hearth Extension
Insulation
Side View
FP550
Sealing gaps.
17
CWC Series Woodburning Fireplace
87D1504
Only unvented gas log sets which have been found to comply with
the Standard for Unvented Room Heaters, ANSI Z21.11.2, are to be
installed in this fireplace.
If installing an unvented gas log set, refer to statement below:
MHSC fireplaces are designed to accept a 1/2" gas
line for installation of an approved gas appliance.
(MHSC manufactures a wide variety of gas logs for
use in MHSC fireplaces.)
Be sure to have the appliance installed in accordance
with building codes.
Gas connection may enter from either left or right side
of the fireplace.
Locate appropriate gas line access hole in the outer
casing of fireplace and remove insulation from gas line
tube. (Fig. 27)
From inside the fireplace, locate the knockout on
the firebrick -- be sure you are on the appropriate or
"gas line" side of the fireplace. Using a flat bladed
screwdriver or small chisel and hammer, carefully tap
around the knockout until it loosens and falls out.
Install 1/2" certified gas pipe through opening. After
gas pipe installation is complete, use insulation that
was removed from gas line tube to repack space
around the pipe. Material should be inserted from out-
side of the fireplace and packed tightly to totally seal
between the pipe and tube.
When installing an ANSI Z21.11.2 ventless
appliance, the finishing materials used for the mantel
must be rated at 250°F or greater.
BTU input of a gas appliance installed in fireplace
should be rated less than 100,000 BTU/Hr.
Gas pipe installation is intended for connection to a
decorative gas appliance only when (1.) incorporat-
ing an automatic shut-off device and (2.) complying
with the Standard for Decorative Gas Appliances for
Installation in Vented Fireplaces (ANSI Z21.60)
CSA draft requirements for Gas-Fired Log Lighters for
Woodburning Fireplaces (Draft No. 4, August 1993).
Decorative gas appliance should be installed in accor-
dance with the National Fuel Gas Code, ANSI Z223.1/
NFPA 54 (latest edition).
FPC560
Gas line access.
1"
Min.
FPC560
WMC
Gas line access
1/29/99
1/2"
Hole in Outer Casing
Gas Line
Tube
Ceramic
Knockout
Supply
Line
Repack Insula-
tion
Hole in Outer
Casing
Ceramic Knock-
out
(Both sides)
18
CWC Series Woodburning Fireplace
87D1504
2-583
Parts page
3/2/99 djt
1
2
3
4
5
6
12
8
10
9
11
15 14a,b
17
16
18
OFF
LOW
13
7
2
MHSC reserves the right to make changes in design, materials, specifications, prices and discontinue colors and products at any time, without
notice.
1. Damper Blade 7551310 7551310
2. Grille Painted (two per fireplace) 20014533 20000714
3. Basket Grate 3041130 3041130
4. Screen (two per fireplace) 26D0131 26D0131
5. Damper Knob (Wood) 7536177 7536177
6. Firebrick - Left Side 3041104 3034102
7. Firebrick - Back 3030102 3034104
8. Firebrick - Right Side 3041105 3034103
9. Firebrick - Hearth 3041103 3034105
10. Screen Rod (two per fireplace) 26D0138 61D0500
11. Top Brick Retainers (three per fireplace) 3030172 3030172
12. Cable Clips (four per fireplace) 7512135 7512135
13. O.S.A. Assy. 20003076 20003076
14a. Door Assy. - Brass Doors 20002984 20002985
14b. Door Assy. - Black Doors 20005309 20005310
15. Door Track Assy. 20003384 20003435
16. Closure Spring 7540264 7540264
17. Blower Assembly 20000620 20000620
18. Variable Speed Control 2544900 2544900
19
CWC Series Woodburning Fireplace
87D1504
The following accessories for this appliance are available from your local distributor. Should you need additional
information beyond what your distributor can furnish, contact: MHSC, 149 Cleveland Drive, Paris, KY 40361; Attn:
Technical Services.
Glass Door — Optional Bi-Fold door set Brushed Brass finish 36GDKBB (CWC400)
42GDKBB (CWC500)
Deluxe Polished finish 36GDKDP (CWC400)
42GDKDP (CWC500)
Pewter finish 36GDKS (CWC400)
42GDKS (CWC500)
Outside Air Termination Completes connection from air kit to out-of-doors AK-MST
Chimney Adapter Converts CWC400 to use 3-wall system TWABR
Hearth Extension Insulation Provides hearth extension floor protection EH2416
Hearth Patch Compound Patch cracks in hearth HPC-1
OGWMC36 Optional brass trimmed, black mesh grille 20000945 (CWC400)
OGWMC42 Optional brass trimmed, black mesh grille 20000946 (CWC500)
20
CWC Series Woodburning Fireplace
87D1504
Round Top Termination Top used to terminate chimney at roof. RLTSK8
(SK8) (Flashing not included.)
Round Top Termination - Top used to terminate chimney at chase. RLTSK8L
Extended (SK8) (Flashing not included.)
Flashing Metal finishing required around Contemporary 8-6-12 with 8" flue:
Termination to prevent rain leakage. 0-6/12 pitch
8-12-12 with 8" flue:
6/12-12/12 pitch
Square Top Housing Top housing of simulated brick pattern S20BR(Red)
available in red, tan or white. Appropriate S20BT(Tan)
adapter required. Flashing included. S20BW(White)
Housing Extensions Extends Square Top Housing on steep pitched 202036
roofs. (Specify red, tan or white)
Square Shroud Square knockdown shroud for RLTSK8L SKDSBL
(SK8) chase applications. (Black)
Square Chase Termination Housing used to terminate chimney through CT100
a chase top. (Unpainted finish)Appropriate
adapter (CTSK) required.(Flashing not included.)
Pyramid Shroud Pyramid knock-down shroud for RLTSK8L PKDSBL
chase application. (Black)
Chase Top Housing Low profile pyramid-style chimney cap used to PLTSK8
(SK8) terminate chimney through a chase. Includes
adapter. (Flashing not included.)
Chase Top Housing Square chimney cap used to terminate chimney SLTSK8
(SK8) through a chase. Includes adapter.
(Flashing not included.)
SK8 Chimney Sections Pipe used to build 8" (SK8) flue systems. SK81 (1' Long)
SK818 (1Z\x' Long)
SK83 (3' Long)
SK84 (4' Long)
SK8 Chimney Elbows Elbow used to create an offset in an 8" SK830-2
chimney system. Only 30˚ elbows available.
Packaged 2 per carton (offset and return).
Firestop Required at each floor level of chimney SKFS2A —
(SK8) installation. (Plus attic on multi-story installation.) (8" straight flue)
SKFS6A —
(8" 30° inclined flue)
Chimney Support Used to support chimney for each of: 30' vertical SKCS8
(SK8) height and 6' of angled chimney run.
Chimney Sections Pipe used build 8" (3-wall) flue systems. 81 (1' Long)
(3-wall) 818 (1Z\x' Long)
83 (3' Long)
84 (4' Long)
Chimney Elbows Used to create an offset in an 8" chimney system. 830A-2
(3-wall) Only 30° elbows available.
Packaged 2 per carton (offset and return).
Round Top Termination Top used to terminate chimney at roof. RLTS8
(3-wall) (Flashing not included)
Round Top Termination Top used to terminate chimney at chase. RLTS8L
Extended (3-wall) Adapter kit included. (Flashing not included)
This manual suits for next models
1
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