Vermont Castings Merrimack Mounting instructions


30004671 5/12 Rev. 6


For Use in North America






Homeowner’s
Installation
and Operating
Manual
Nous recommandons que nos appareils de chauffage
au bois soient installés et entretenus apr des
professionnels qui ont été accrédités aux É.-U. par le
National Fireplace Institute® (NFI) comme étant des
spécialistes du NFI en matière d’appareilsde chauffage
au ois, ou qui sont accrédités au Canada
dans le cadre du Programme
de formation technique
en énergie du bois (WETT)
4671
Merrimack cover
227-S-37-6.2

2
Merrimack Large Insert
30004671















Specications .............................................................3
Installation ..................................................................4
Operation ....................................................................9
Maintenance .............................................................13
Optional Accessories ................................................16
Replacement Parts ...................................................17
Warranty ...................................................................19

 Fuels used in gas, woodburn-
ing or oil red appliances, and the products of combus-
tion 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
Thank you for purchasing a Vermont Castings Merrimack Large Insert, an efcient wood stove carefully engineered to
bring you the latest in wood combustion principles and modern foundry technology.
This stove transforms a traditional masonry replace into a powerful heater. You can count on years of comfortable heat-
ing and pleasurable re-viewing if you operate and maintain it according to the directions in this Owner’s Guide.
This Insert has been tested and listed by OMNI-Test Laboratories of Portland, Oregon to UL1482-1996(R2006) for the
United States and ULC S628-93 for Canada. This Insert is listed to, and in compliance with, the standards set forth by
the Federal Environmental Protection Agency, 40 CFR Part 60.532(b), as stated on the permanent label attached to the
stove.
This manual describes the installation and operation of this Insert. This heater meets the U.S. Environmental Protection
Agency’s emission limits for wood heaters sold after July 1, 1990. Under specic test conditions this heater has been
shown to deliver heat at a rate ranging from 10,750 to 31,780 BTU/hr.
For more complete details on stove performance and specications, please refer to Page 3.
The Merrimack Large Insert is designed, tested and listed for burning wood. Do not burn other fuels.
Installation or service of the Merrimack Large Insert should be performed only by a qualied installer, preferably NFI or
WETT (Canada) certied.
Please read entire manual before you install and use your new Insert.
Failure to follow these instructions may result in property damage, bodily injury or even death.

3
Merrimack Large Insert
30004671


EPA Emissions Rating .......................................3.6 g/hr
Range of heat output*.............. 10,750 - 31,780 BTU/hr
Maximum heat output** ..........................55,000 BTU/hr
Area heated*** ................................... up to 2,000 sq. ft.
Size of wood splits .......................... up to 22” (560 mm)
Fuel Capacity.......................................... 40 lbs. (18 kg)
Loading ..................................................................Front
Flue size .................................................... 6” (150 mm)
Fireplace Insert weight ....................... 480 lbs. (218 kg)
Primary Air Control ............................................ Manual
Glass panel.......................... High-temperature ceramic
Flue exit position...................................................... Top
Blower rating...............................150 cfm. (115V, 60Hz)
Power Cord Length................... 6 foot useable installed
*Under specic test conditions used during EPA emissions
standard testing.
**This value can vary depending on how the unit is oper-
ated, and the type and moisture content of the fuel used.
The gure shown is based on maximum fuel consumption
obtained under laboratory conditions and with average
efciencies.
***These values are based on operation in building-code
conforming homes under typical winter climate conditions
in New England. If your home is of nonstandard construc-
tion (e.g. unusually well insulated, not insulated, built
under ground, etc.) or if you live in a more severe or more
temperate climate, these gures may not apply. Since so
many variables affect performance, consult your Vermont
Castings’ Authorized Dealer to determine realistic expecta-
tions for your home.
 Merrimack Large Insert dimensions.
2956” (740 mm)
246M” (629 mm)
126QE”
(313 mm)
266QE”
(668 mm)
17556QE” (449 mm)
2356QE”
(605 mm)
4671
Merrimack dims
76QE”
(183 mm)
3156O" (800 mm) 256” (645 mm)

4
Merrimack Large Insert
30004671
       
       

    




The Merrimack Large Insert is listed for installation within
a properly built masonry or heat circulating, masonry-type
replace that is constructed in accordance with the require-
ments of recognized building codes. A heat-circulating
masonry-type replace must conform to building code
standards for masonry replaces, and must consist of a
factory-built metal rebox with air circulation pathways
that are surrounded by masonry materials. Air circulation
pathways must not be blocked by the insert or surround
panels.
The replace and chimney must be clean and structurally
sound. Have them inspected by a qualied professional
chimney sweep, a mason, or your Vermont Castings’
Authorized Dealer before the Merrimack Large Insert is
installed. Any deterioration (cracks, loose mortar or loose
bricks) must be repaired.
Codes may permit removal of the damper in order to make a
positive vent connection between the rebox and the chim-
ney. However, the replace should not be modied in any
way without rst checking with your local building inspector
or re marshal. Provision should be made to restore the
replace to its original condition if the insert is removed.
Do not remove bricks or mortar that may jeopardize the
compliance of the replace with local building codes.



Chimney requirements differ for the U.S. and Canada.
Specications for each are listed below. Connect the
insert to the chimney in accordance with local codes and
the requirements of the listing agency as specied in this
manual.

Chimney height should be no less than 15’ (4.5 m) above
the hearth and no more than 35’ (10.5 m).
The chimney should extend at least 3’ (914 mm) above the
highest point where it passes through a roof, and at least
2’ (610 mm) higher than any portion of a building within
10’ (3 m). (Fig. 2)
      
       



 

• A connector must extend from the ue collar
to the ue liner.
• The cross sectional area of the ue must be less
than or equal to three times the area of the ue
collar. If larger, the chimney must be re-lined.
• Means must be provided to prevent room air
passing to the chimney cavity.
• Provision must be made for removal of the
insert to clean the chimney ue.

• While not required in most jurisdictions in the U.S.,
MHSC strongly recommends that a full stainless
steel chimney liner be installed for the insert to the
chimney top to increase overall performance and to
ease and reduce yearly maintenance.
• A masonry chimney must be well-constructed and
must meet minimum code requirements. The chim-
ney ue should have a code-approved liner made of
masonry or pre-cast refractory tiles, straight or ex-
ible stainless steel pipe, or a poured-in-place liner.
An unlined chimney must be relined professionally.
• The chimney must have a nominal ue size of 6” (152
mm) diameter or 28 square inches (181 cm2) but no
greater than 3 times larger or 85 square inches (548
cm2). A chimney larger than this must be re-lined.
Be aware that a chimney originally designed for replace
use may perform differently when used to vent an air-
controlled appliance such as your Merrimack Large Insert
- even if the ue is less than 3 times larger than the ue
collar. For example, a chimney on an outside wall may
not heat up enough to sustain an adequate draft. Such a
ue can often be improved if it is relined to reduce its size
and/or insulated to keep it warmer.
2' Min.
2' Min.
3'
Min.
0 To 10'
3'
Min.
0 To 10'
AC617
RLTSKC8
2/11/98
AC617
Reference
Point
 The 2’-3’-10’ rule for chimneys.

5
Merrimack Large Insert
30004671
• A positive ue connection must be made between
the Insert and the rst masonry tile or prefabricated
metal chimney section. A positive ue connection
consists of a plate that seals or replaces the replace
damper and a section of chimney connector that
passes through the plate into the chimney.
• The chimney connector must be a minimum equiva-
lent to a 6” (152 mm) diameter opening and must be
24 gauge or heavier stainless steel.
Chimney Connection systems are available from a variety
of manufacturers. Your Vermont Castings dealer can rec-
ommend a system that will best meet the requirements of
your particular installation.

• The chimney must be sealed off from room air, ei-
ther by a plate at the damper level or by sealing the
replace opening.
• Unused openings to the ue must be sealed with ma-
sonry to the thickness of the chimney wall. Openings
sealed with pie plates or wallpaper are a hazard.
In the event of a chimney re, ames and smoke
may be forced from the openings.


• This replace insert must be installed with a
continuous chimney liner of 6” (152 mm) diam-
eterextending from the replace insert to the top
of the chimney. The chimney liner must conform
to the Class 3 requirements of CAN/ULC-S635,
Standard for Lining Systems for Existing Masonry
or Factory-Built Chimneys and Vents, or CAN/
ULC-S640, Standard for Lining Systems for New
Masonry Chimneys.
• The opening of the replace around the insert
must be sealed to prevent room air passing to
the replace cavity.
• Existing air-circulation chambers in a replace
with a steel liner may not be blocked.
• Provision must be made for removal of the insert
to clean the chimney ue.
• The existing replace damper (if any) should be
locked in the open position.
• A permanent metal warning label must be afxed
to the back of the replace stating the replace
may have been altered to accommodate the in-
sert, and may be unsafe to use as a conventional
replace. (A Fireplace Modication Tag is included
in the hardware bag inside the Merrimack Large
Insert.)

The Merrimack Large Insert will t many replaces. To
conrm that it will t yours, measure the lintel depth, plus
the height, width, and depth of your replace and hearth.
Compare them to the measurements in the accompany-
ing chart. If you choose to install a new hearth over an
existing replace hearth, be sure to take its thickness into
consideration when measuring both front and back height
of the replace and clearances to any existing trims and
mantels.
 The clearance between the Merrimack Large Insert
and the mantel, top trim and side trim cannot be reduced
by installing shields.
Another requirement to consider is the clearance for mov-
able items such as tables, bookcases, rugs, furnishings, and
your woodbox. All combustible materials of this type should
be a minimum of 48” (1220 mm) from the front surface of
the Merrimack Large Insert. Be sure that family members
are aware of this requirement as well, so they too will keep
objects a safe distance from the stove.
A,I
BC
D,J
E
D,J
H
CE
FP1084
winterwarm
fireplace minimum dimensions
3/01

A. Width at Face 29C\v” (756 mm)
B. Width at Dimension ‘C’ 25” (635 mm)
C. Depth1 18¹\₂” (470 mm)
D. Height at Face 23C\v” (603 mm)
E. Height at Dimension ‘C’ 23C\v” (603 mm)

H. Lintel depth 9” (229 mm)
I. Width2 45” (1143 mm)
J. Height2 32” (813 mm)
FP1084
1. The minimum depth must be maintained from the oor of the replace
to a height of 21¹\₂” (540 mm)
2. Though the Merrimack Large Insert will t into larger replaces, the
decorative optional MHSC Surround Panels will not completely cover the
replace opening if these dimensions are exceeded. Custom made trim
pieces may be used.
 Use these measurements to conrm that the Merrimack
Large Insert will t into your masonry replace.