MHSC BUF400 User manual
61D1013 2/10 Rev. 8
2 61D1013
Before You Start .....................................................5
Firebox External Dimensions .................................6
Minimum Hearth Dimensions .................................7
Forced Air Kit .......................................................14
Brass or Chrome Louvers ....................................14
Brass or Chrome Trim ..........................................14
Firebrick ...............................................................14
Optional Wide Canopy .........................................14
61D1013 3
9. The installation must conform with local codes or,
in the absence of local codes, with the
10. This unit complies with ANSI Z21.91.2001 ventless
firebox enclosures for gas-fired unvented decorative
room heaters.
11. Do not install heater in a bathroom or bedroom.
12. Correct installation of the ceramic fiber logs, proper
location of the heater, and annual cleaning are
necessary to avoid potential problems with soot-
ing. Sooting, resulting from improper installation
or operation, can settle on surfaces outside the
fireplace. See log placement instructions for proper
installation.
13. Avoid any drafts that alter burner flame patterns.
Do not allow fans to blow directly into fireplace. Do
not place a blower inside burn area of firebox. Ceil-
ing fans may create drafts that alter burner flame
patterns. Sooting and improper burning will occur.
14. Candles, incense, oil lamps, etc. produce
combustion byproducts including soot. Vent-free
appliances will not filter or clean soot produced
by these types of products. In addition, the smoke
and/or aromatics (scents) may be reburnt in the
vent-free appliance which can produce odors. It
is recommended to minimize the use of candles,
incense, etc. while the vent-free appliance is in
operation.
Please leave these instructions with the appli-
ance.
Please retain these instructions for future refer-
ence
.
Read these instructions carefully before installing or trying to operate a vent-free gas heater in this firebox.
1. Due to high temperatures, the appliance should
be located out of traffic and away from furniture
and draperies.
2. Children and adults should be alerted to the
hazard of high surface temperature and should
stay away to avoid burns or clothing ignition.
3. Young children should be carefully supervised
when they are in the same room with the apli-
ance.
4. Do not place clothing or other flammable mate-
rial on or near the appliance.
5. Any safety screen or guard removed for ser-
vicing an appliance, must be replaced prior to
operating the heater.
6. Installation and repair should be done by a
qualified service person.
7. To prevent malfunction and/or sooting, an
unvented gas heater should be cleaned
before use at least annually by a professional
service person. More frequent cleaning may
be required due to excessive lint from carpet-
ing, bedding material, etc. It is imperative that
control compartments, burners and circulating
air passageways be kept clean.
8. Early signs
of carbon monoxide poisoning are similar to the
flu with headaches, dizziness and/or nausea. If
you have these signs, obtain fresh air immediately.
Have the heater serviced as it may not be operating
properly. Continuedonpage4
4 61D1013
Continuedfrompage3
15. An unvented gas-fired heater uses air (oxygen)
from the room in which it is installed. Provisions for
adequate combustion and ventilation air must be
provided. See installation guidelines.
16. Keep room area clear and free from combustible
materials, gasoline and other flammable vapors
and liquids.
17. Unvented gas heaters are a supplemental zone
heater. They are not intended to be a primary heat-
ing appliance.
18. Unvented gas heaters emit moisture into the living
area. In most homes of average construction, this
does not pose a problem. In houses of extremely
tight construction, additional mechanical ventilation
is recommended.
19. During manufacturing, fabricating and shipping,
various components of this appliance are treated
with certain oils, films or bonding agents. These
chemicals are not harmful but may produce annoy-
ing smoke and smells as they are burned off during
the initial operation of the appliance; possibly caus-
ing headaches, or eye or lung irritation. This is a
normal and temporary occurrence.
The initial break-in operation should last two to three
hours with the burner at the highest setting. Provide
maximum ventilation by opening windows or doors
to allow odors to dissipate. Any odors remaining
after this initial break-in period will be slight and will
disappear with continued use.
20. Input ratings are shown in BTU per hour and are for
elevations up to 2,000 feet. For elevations above
2,000 feet, input ratings should be reduced 4 per-
cent for each 1,000 feet above sea level. Refer to
the National Fuel Gas Code.
21. The appliance and its appliance main gas valve
must be disconnected from the gas supply piping
system during any pressure testing of that system
at test pressures in excess of 1/2 psig (3.5 kPa).
22. The appliance must be isolated from the gas supply
piping system by closing its equipment shutoff valve
during any pressure testing of the gas supply piping
system at test pressures equal to or less than 1/2
psig (3.5 kPa).
23. Do not use this room heater if any part has been
under water. Immediately call a qualified service
technician to inspect the room heater and to replace
any part of the control system and any gas control
which has been under water.
24. Never burn solid fuels in a fireplace where a
unvented room heater is installed.
25. Always have a fireplace screen in place when the
appliance is in operation, and unless other provi-
sions for combustion air are provided, the screen
shall have an opening(s) for induction of combus-
tion air.
26. Do not fill spaces around the firebox with insulation
or other materials. These spaces must be main-
tained to prevent the firebox from coming in contact
with combustible materials.
We suggest that our gas hearth
products be installed and
serviced by professionals who
are certified in the U.S. by the
National Fireplace Institute®
(NFI) as Gas Specialists.
61D1013 5
The BUF400 and BUF500 are vent-free fireboxes and feature a self contained heat-circulating system. This unit also
features a 2-in1, flexible-face system that converts the circulating system into a radiant system in seconds.
This installation manual will enable you to obtain a safe, efficient and dependable installation of your vent-free
fireplace system.
Do not alter or modify the firebox or its components under any circumstances. Any modification or alteration of
the firebox system, including but not limited to the firebox and accessories, may void the warranty, listings and
approvals of this system and could result in an unsafe and potentially dangerous installation.
Carefully inspect the contents for shipping damage. If any parts are missing or damaged, immediately inform the
dealer from whom you purchased the appliance. Do not attempt to install any part of the appliance unless you
have all the parts in good condition.
Check your packing list to verify that all listed parts have been received. You should have the following:
1. Vent-Free Gas Firebox 3. Five (5) sheet metal screws for canopy
2. Canopy 4. Installation and Operating Instructions
• Phillips screwdriver • Square • Framing materials
• Hammer •
Piping complying with local codes
• Wall finishing materials
• Saw and/or sabersaw • Tee joint • Caulking material (noncombustible)
• Level • Pipe wrench • Fireplace surround materials (noncombus-
tible)
• Measuring tape • Pliers
• Electric drill and bits • Pipe sealant approved for use with propane/L.P.G. (resistanttosulfurcompounds)
Refer to the installation instructions provided with the log sets for items required for log set installation.
6 61D1013
BUF400: 2413/16"
23/16"
69/16"
103/8"
147/16"
BUF400: 40"
BUF400: 36"
241/4"
61/2"
219/16"
21"
34"
6"
2"
BUF500: 3013/16"
BUF500: 46"
BUF500: 42"
In planning the installation for the appliance it is necessary to determine where the unit is to be installed and whether
optional accessories are desired. Gas supply piping should also be planned. The following steps represent the
normal sequence of installation. Each installation is unique, however, and might require a different sequence.
1. Position firebox prior to framing or into prepared framing.
2. Field wire main power supply to models with fan kit. (Electrical connections should only be performed by
an experienced, licensed /certified tradesman). Electrical outlet is needed with fan kit.
3. Plumb gas line. (Gas connections should only be performed by an experienced, licensed/certified trades-
man).
4. Install vent-free gas log heater per the instructions provided with the vent-free gas log heater.
5. Complete finish wall material, surround and optional hearth extension to your individual taste.
61D1013 7
17"
21
1
/
2
"
BUF400: 351/2
"
BUF400: 203/8
"
BUF500: 263/8
"
BUF500: 41
1
/
2
"
Carefully select the best location for installation of your
vent-free firebox. The following factors should be taken
into consideration:
• Clearance to side wall, ceiling, woodwork and windows.
See “Clearances/Height Requirements on page 8.
Minimum clearances to combustibles
• Location must not be affected by drafts caused by
kitchen exhaust fans, ceiling fans, return air registers
for forced air furnaces / air conditioners, windows or
doors.
• Installation must provide adequate ventilation and
combustion air.
•
• Location should be out of high traffic or windy or drafty
areas.
•
• Never obstruct the front opening of the vent-free firebox or restrict the flow of combustion and ventilation
air.
• Minimize modifications to existing construction. Refer to Figure 3 below for location suggestions.
• Do not install in the vicinity where gasoline or other flammable liquids may be stored. The vent-free firebox
must be kept clear and free from these combustible materials.
8 61D1013
9"
Minimum
42"
Minimum
9"
Minimum
Ensure that minimum clearances shown in Figures 4 through 7 are maintained. Left and right clearances are
determined when facing the front of the firebox.
Follow these instructions carefully to ensure safe installation. Failure to follow these requirements may create a
fire hazard.
1. The clearance from the inside of the appliance to any combustible wall should not
be less than 9". SeeFigure4.
2. The ceiling must be at least 42” from the top of the firebox opening. SeeFigure4.
3. The appliance may be placed against a combustible back wall.
Continuedonpage10
and
61D1013 9
12"
10"
8"
6"
21/2"
12"
16"
19"
21"
23"
and
4. The canopy supplied with the unit
must be installed. If a combustible mantel is installed,
it must meet the clearance requirements as shown in
Figure5.
This inner chamber firebox floor must be installed at least 5" above any combustible
flooring material, such as carpeting or asphalt tile, which is closer than 14" to the base of the firebox. See
Figure6.
The inner chamber firebox floor may be installed nearer to the floor if a minimum of 14" of noncombustible
material such as slate or marble is installed between the base of the firebox and the combustible flooring.
SeeFigure7.
Non-Combustible
Material
5" Minimum
14" Minimum
Can Be
Less than 5" Non-Combustible
Material
10 61D1013
205/16"
400: 401/4"
400: 661/8"
400: 2413/16"
500: 3013/16"
500: 461/4"
500: 725/8"
400: 463/4
"
500: 513/8
"
400: 331/16"
500: 365/16"
400: 123/4"
500: 16"
400: 2413/16"
400: 401/4"1/2" or 5/8"
203/4"
500: 3013/16"
500: 461/4"
341/4"
400: 401/4"
500: 461/4"
400: 2413/16"
203/4"
400: 403/4"1/2" or 5/8"
500: 3013/16"
500: 463/4"
Firebox framing can be built before or after the appliance is set in place. Construct firebox framing following
Figures8through11 and the chart below for your specific installation requirements. SeeFigure1onPage6for
firebox dimensions. The framing headers may rest on the top of the firebox standoffs.
The firebox may be installed directly on a combustible floor or raised on a platform of an appropriate height.
When the firebox is installed directly on carpeting, tile, or other combustible material, other than wood flooring,
the firebox shall be installed on a metal or wood panel extending the full width and depth of the enclosure.
61D1013 11
1. Bend out the nailing flanges located on each side of the firebox.
2. Slide the firebox into prepared framing or position firebox in its final position and frame later.
3. Level the firebox by checking the top edge of the firebox. Shim if necessary.
4. Anchor firebox to the side framing members using 8d nails or other suitable fasteners. SeeFigure12.
5. The canopy must be installed for safe operation of the heater. See page 13 for canopy installation details.
Nail Sides
Through Nailing
Flanges
12 61D1013
Consult all local codes. All gas piping must be installed to comply with local codes, or in the absence of local
codes, with the latest edition of the National Fuel Gas Code ANSI Z223.1/NFPA54.
Remove the baseplate for ease of gas line installation. Remove three (3) screws along the front edge of the base-
plate. Remove four (4) screws which secure the baseplate to the combustion casing (two at rear and one along
each side). Replace baseplate prior to connecting gas line to heater. Consult heater installation and operating
instructions for correct installation of the heater into the firebox.
The 1/2" gas line may enter either from the left side or right side of the firebox. Gas access holes are provided on
both sides of the firebox.
A listed manual shutoff valve must be installed upstream of the appliance. A union tee and plugged 1/8" NPT
pressure tapping point should be installed upstream of hte appliance.
IMPORTANT:Installmaingasvalve(equipmentshutoffvalve)inanaccessiblelocation.Themaingasvalveis
forturningonorshuttingoffthegastothefireplace.
A sediment trap may be upstream of the heater to prevent moisture and contaminants from passing through trap
to the heater controls and burners. Failure to do so could prevent the heater from operating reliably. Consult
applicable codes.
An external regulator must be used on all propane / L.P.G. heaters, in addition to the regulator fitted to the heater,
to reduce the supply tank pressure to 13" w.c. (maximum). Any copper tubing used to supply propane / L.P.G.
from the tank must be internally tinned.
After completing connection, test all gas joints from the gas meter to the gas heater regulator for leaks. Using
soap and water solution or a gas sniffer. DO NOT USE AN OPEN FLAME.
61D1013 13
A canopy is furnished with each firebox and MUST be installed for safe operation. SeeFigure14.
1. Locate three (3) holes at the top of the front frame. SeeFigure13.
2. Align the canopy with the holes in the top of the frame.
3. Secure canopy to front of frame with screws provided. SeeFigure13.
Canopy
Screws
Front
Frame
14 61D1013
If you are installing the forced air kit, Model FA2A, see the installation instructions provided with the kit for electri-
cal wiring requirements, or the blower installation section. The firebox must be connected to main power supply
at time of firebox installation. The blower must be installed prior to the installation of the vent-free heater. The
electrical connections must be made before the firebox is framed and enclosed in the finished walls.
61D1013 15
1
2
3
3
1 Canopy 1 26D4568 26D4706
2 Screen Panel 2 26D0131 26D0187
3 Screen Rod 2 26D0132 26D0133
4 Rear Refractory 1 61D0102 61D0107
5 Side Refractory 2 61D0101 61D0101
6 Bottom Refractory 1 61D0100 61D0106
7 Outside Air Kit 1 AK-4 AK-4
16 61D1013
8'max.
1. Locate combustion air assembly at an exterior location which is not likely to be accidentally blocked in any
manner. Locate assembly a min. of 12" above the snow line to prevent blockage by snow accumulation.
2. Never mount the combustion air inlet assembly in a garage or storage area where combustible fumes such
as gasoline might be drawn into the fireplace.
3. Combustion air can be drawn from the crawl space under a house when an adequate supply of air is provided
by open ventilation.
4.
5. Locate air supply inlet at least 3' away from any appliance vent terminal.
6. Avoid extremely long runs and numerous turns in the duct leading from the fireplace to the combustion air
assembly. These conditions increase the resistance to the free flow of air through the duct. SeeFigures14
through17for methods of installing the outside air for combustion assemblies.
Above
Snow
Level
Ground
Level
Basement
Wall
Inlet Grill in
Soffit
(Overhang)
Inside Wall
Outside
Wall
Duct Extended
to Miss Joist
To Outside Wall
Note:Fireplacemodelinillustrationsmaynotberepresentativeofyourappliance.
61D1013 17
The use of outside air for combustion is optional unless required by building codes. It is only necessary to supply
outside combustion air to one side of the fireplace. Use the model AK4 combustion air kit.
1. Remove the cover plate from the 4" outlet opening location on the left
or right outside of the fireplace.
2. Place the insulation ring between the AK-4 starting collar and fire-
place wall.
3. Place the starting collar (4") into the hole on the side of fireplace. Fasten it in place with the four sheet metal
screws provided. SeeFigures18and19.
4. Attach outside duct to starting collar with duct clamp or screws. SeeFigure19.
Insulation Ring
AK-4 Starting
Collar
Sheet
Meal
Screws
Left Side of
Fireplace
Shorter End
of Air Starting
Collar
Air Starting
Collar
Duct
Screws
Left Side of
Fireplace
5. Cut a 6-inch diameter opening for model AK-4 in the
outside wall covering where the outside vent is to be
located. SeeFigure20.
6. Select and cut a piece of duct long enough to attach
to the fireplace and stick out at least 3" beyond the
face of the wall to which the AK-4 inlet air vent will be
attached. SeeFigure19.
Nail
Holes
6" Diameter
Hole
Duct
Extending
3"min.
AK-4 Inlet
Air Vent
Screw
Screws
Continued
18 61D1013
7. If the duct is the insulated type, push the insulation back from one
end of the duct approximately 2". SeeFigure21.
8. Slip the exposed end of the duct over the starting collar on the
fireplace.
9. Using the sheet metal screws provided, secure the duct end to the
collar attached to the fireplace.
10. Nail or screw the combustion air assembly to the surface of the
wall.
1. Push insulation back approximately 2" from the end of each duct.
2. Slip each duct over duct connector until an equal length of connector extends into each duct.
3. Place duck clamp over the end of each duct. Tighten duct clamp down snuggly.
4. Push insulation back into place and over duct clamp.
Approximately
2"
Insulation
Duct
Connector
Duct Clamp
61D1013 19
The following components are warranted for life to the original owner, subject of proof of purchase:
Firebox, Combustion Chamber, Heat Exchanger, Grate, and Stainless Steel Burners.
The following components are warranted for 5 years to the original owner, subject of proof of purchase:
Vent Free Ceramic Fiber Logs, Catalytic Filter and Aluminized Burners.
MHSC warrants the components and materials in your gas appliance to be free from manufacturing and
material defects for a period of two years from date of installation. After installation, if any of the compo-
nents manufactured by MHSC in the appliance are found to be defective in materials or workmanship,
MHSC will, at its option, replace or repair the defective components at no charge to the original owner.
MHSC will also pay for reasonable labor costs incurred in replacing or repairing such components for
a period of two years from the date of installation. Any products presented for warranty repair must be
accompanied by a dated proof of purchase.
This Limited Lifetime Warranty will be void if the appliance is not installed by a qualified installer in accor-
dance with the installation instructions. The Limited Lifetime Warranty will also be void if the appliance
is not operated and maintained according to the operating instructions supplied with the appliance, and
does not extend to (1) firebox/burner assembly damage by accident, neglect, misuse, abuse, alteration,
negligence of others, including the installation thereof by unqualified installers, (2) the costs of removal,
reinstallation or transportation of defective parts on the appliance, or (3) incidental or consequential
damage. All service work must be performed by an authorized service representative.
This warranty is expressly in lieu of other warranties, express or implied, including the warranty of mer-
chantability of fitness for purpose and of all other obligations or liabilities. MHSC does not assume for it
any other obligations or liability in connection with the sale or use of the appliance. In states that do not
allow limitations on how long an implied warranty lasts, or do not allow exclusion of indirect damage,
those limitations of exclusions may not apply to you. You may also have additional rights not covered in
this Limited Lifetime Warranty.
MHSC reserves the right to investigate any and all claims against the Limited Lifetime Warranty and
decide upon method of settlement.
1. Contact your supplier. Make sure you have your warranty, your sales receipt and the model/serial
number of your MHSCC product.
2. DO NOT ATTEMPT TO DO ANY SERVICE WORK YOURSELF.
149 Cleveland Drive • Paris, Kentucky 40361
www.mhsc.com
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