mFi MASON-LITE MGFP39 User manual

Instructions
Models MGFP39/44/49
Equipped with Safety Pilot System / Remote Control Valve
Low profile or pan
burners are not
allowed for use in
these units without a
metal base
Do not store or use gasoline or other
ammable vapors and liquids in the
vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch; do
not use any phone in your building.
• Immediately call your gas supplier from
a neighbor’s phone and follow the gas
supplier’s instructions.
• If you cannot reach your gas supplier,
call the re department.
Installation and service must be
performed by a qualied installer, service
agency, or the gas supplier.
WARNING:
If the information in these instructions is
not followed exactly, a re or explosion
may result causing property damage,
personal injury or death.
REV 1/7/21
B-vented Gas Appliances with Masonry Firebox
The logs and burner must be permanently installed in and
are only for use in this appliance. This appliance must be
connected to a working ue meeting the requirements of
the ANSI Z21.50 standard.
Solid-fuels shall not be burned in this appliance.
This appliance must be vented vertically through the
roof. This appliance is not for installation in manufactured
or mobile homes. The installation, including provisions
for combustion, ventilation air, and required minimum
permanent vent opening, must conform with the National
Fuel Gas Code (ANSI Z223.1/NFPA 54) and applicable
local building codes. This gas appliance is designed to
burn with yellow ames; thus adequate ventilation is
absolutely necessary.
IMPORTANT: READ THESE INSTRUCTIONS
CAREFULLY BEFORE STARTING
INSTALLATION OF THIS APPLIANCE.
WARNING:
This gas appliance must not be connected to a chimney
fuel servicing a solid fuel burning appliance.
Do not store gasoline or other ammable vapors and liquids in the vicinity of this or any other appliance.
ReportNo. 08-154
ICC Evaluation Services
Report No. 2401
This appliance is only for use with the type
of gas indicated on the rating plate. This
appliance is not convertible for use with
other gases, unless a certied kit is used.
Installer: Leave these instructions with the consumer.
Consumer: Retain for future reference.
Equipped with Safety
Pilot System / Remote
Control Valve

1
Contents ..........................................................................................................................................Pg. 1
Appliance Parts List .........................................................................................................................Pg. 2, 3
Burner and Logs Parts List ..............................................................................................................Pg. 4
Product Overview ............................................................................................................................Pg. 5, 6
Clearance To Combustibles............................................................................................................. Pg. 7
Mason-Lite Appliance & Chimney Systems ..................................................................................... Pg. 7
Chimney System Heights ................................................................................................................Pg. 7
Supporting Floor Systems ...............................................................................................................Pg. 8, 9
What You Will Need .........................................................................................................................Pg. 10
Appliance Assembly Procedures .....................................................................................................Pg. 11, 12
Mason-Lite Firebrick Liner ...............................................................................................................Pg. 13
Installing Outside Air ........................................................................................................................Pg. 13~14
Mason-Lite Chimney Systems ......................................................................................................... Pg. 14
Determining Finished Height for Appliance......................................................................................Pg. 14, 15
Installing Vent Plate and Chimney Systems ....................................................................................Pg. 15
Venting Installation...........................................................................................................................Pg. 16
Specifying Chimney Heights............................................................................................................ Pg. 17
Chimney Termination Units.............................................................................................................. Pg. 17
Important Pre-installation Information.............................................................................................. Pg. 17
Install Spill Switch and Ba󰀪e Assembly ..........................................................................................Pg. 18
Owner’s Operation & Precautions ................................................................................................... Pg. 18, 19
Installing the Valve/Control Box Assembly.......................................................................................Pg. 18
Attaching the Burner and Grate.......................................................................................................Pg. 19
Checking and Adjusting the Pilot ..................................................................................................... Pg. 19
Placing the Decorative Lava Rock................................................................................................... Pg. 19
Adjusting Air Mixers .........................................................................................................................Pg. 19
Log Placement................................................................................................................................. Pg. 20
Lighting and Operating Instructions.................................................................................................Pg. 21
Maintenance and Service ................................................................................................................Pg. 22
Troubleshooting ...............................................................................................................................Pg. 22
Appendix I........................................................................................................................................ Pg. 23
Appendix II....................................................................................................................................... Pg. 24
Warranty ..........................................................................................................................................Pg. 25
CONTENTSCONTENTS
Below is a sample picture of the rating plate that is located inside the lower dome side of your appliance. Model Number, Date Of Manufacture
and Serial Number should be stamped on the plate where indicated.
NG LP
7. HOLES: 4X Ø 0.14” THRU
6. CLEAR BOXES NEXT TO MODEL NUMBERS ARE TO BE STAMPED DURING MANUFACTURE OF FIREPLACE.
5. LARGE TEXT TO BOLD UPPERCASE ARIAL, 10 PT. MIN. (WHERE SHOWN).
4. SMALLEST TEXT TO BE ARIAL, 8 PT. MIN (WHERE SHOWN).
3. ALL TEXT AND GRAPHICS TO BE BLACK ON A CONTRASTING, CLEAR ALUMINUM BACKGROUND.
2. FINISH: CLEAR, PROTECTIVE COATING AT RATED TEMPERATURE IN NOTE 1.
1. MATERIAL: CLASS IIIA , .024 THICK ALUMINUM RATED AT 302°F (150°C).
NOTES: UNLESS OTHERWISE SPECIFIED
DESCRIPTION: LABEL, RATING, MGFP
P/N: MFP587
REV. C
DATE: 02/22/2015
LAST MODIFIED BY: CB
Doc File Name: MFP587C_RATING PLATE, MGFP
REVISION COMMENTS:
REV “C”: REMOVED REFERENCE TO
MFPST43 IN “LISTED CHIMNEYS”
PARAGRAPH; UPDATED ADDRESS, ZIP
92504 WAS 92514
REV “B”: ADDED P/N, PREVIOUS FILE DID
NOT HAVE REVISION CONTROL OR PART
NUMBER ASSIGNED.
UPDATED MFI ADDRESS.
ADD P/N ON PLATE.
4.25” 4.00”
6.5”
6.25”
.12”
ICC Evaluation
Services Report
No. 2401
MFI
Masonry
Fireplace
Industries, LLC
6391 Jurupa Ave.
Riverside, CA 92504
DATE OF MFG. SERIAL No.
This appliance is not for installation in manufactured or mobile homes.
MFP587C
GAS
TYPE:
FOR MANTEL CLEARANCES
CONSULT OWNER’S MANUAL
DO NOT REMOVE THIS LABEL
See MFI’s installation and operating instructions for
this model. Contact local building officials about
restrictions and installation specifications in your area.
THIS FIREPLACE IS DESIGNED
FOR USE ONLY WITH THE ANSI
Z21.50 DECORATIVE GAS LOGS
AND BURNER TESTED AND
APPROVED FOR THIS FIREPLACE.
Consult instructions included with this
firebox for further information.
!
WARNING:
Use only approved, listed chimneys
MGFP-39/44/49:
10” B-Type Vent and DM-12-10” system.
Chimney Heights:
Max.: 40 ft.
Min.: 14 ft. (17 ft. with 1 or 2 offset
sections maximum)
IMPORTANT: Refer to pipe
manufacturer’s instructions.
!
WARNING:
THIS FIREPLACE HAS BEEN TESTED
FOR USE ONLY WITH APPROVED
GLASS DOORS. TO REDUCE THE
RISK OF FIRE OR INJURY, CONSULT
OWNER’S MANUAL.
THIS APPLIANCE NEEDS FRESH AIR FOR SAFE OPERATION AND MUST BE INSTALLED
SO THERE ARE PROVISIONS FOR ADEQUATE COMBUSTION AND VENTILATION AIR.
!
WARNING: THIS FIREPLACE IS NOT INTENDED FOR BURNING SOLID FUELS.
!
WARNING: This gas appliance must not be connected to a chimney fuel servicing a solid fuel burning appliance.
!
FIREPLACE CLEARANCES TO COMBUSTIBLES:
UNIT FRONT, SIDES, REAR...............................0” (0 mm)
COMBUSTIBLE FLOOR......................................0” (0 mm)
COMB. SHEATHING ABOVE OPENING TOP.....8” (200 mm)
SHEATHING OR TRIM TO OPENING SIDES....12“ (300 mm)
OPENING TO SIDE WALL..................................20”(500 mm)
HEARTH EXTENSION BEYOND SIDES............12“ (300 mm)
INSULATION FROM FIREBOX............................0” (0 mm)
The installation, including provisions for combustion, ventilation air, and required minimum permanent vent opening,
must conform with the National Fuel Gas Code (ANSI Z223.1/NFPA 54) and applicable local building codes.
MODEL
No.:
MGFP-39 MGFP-44 MGFP-49
LARR No. 25924
Tested &
Listed By
Report No.
08-154
PFS
®
US
EXAMPLE ONLY

2
Appliance Parts ListAppliance Parts List
See Page 8 and 9 for framing anchoring components.
WARNING
Failure to position the parts in
accordance with these diagrams or
failure to use only parts specically
approved with this appliance may result
in property damage or personal injury.
Figure 1
1
5
7
2
8
4
9
15
14
10
12
6A
3
3A
7
8
11
10
6B
6C

3
* ITEMS NOTED ARE SOLD SEPARATELY.
ITEMS INDICATED AS “NOT SUPPLIED” CAN BE
OBTAINED FROM YOUR LOCAL HARDWARE STORE.
Optional Outside Ø4”
Combustion Air Kit
Model No.: MFP4-AK
(Ø4” Ducting not included)
Only the following
doors have been tested
and approved for use
with this fireplace:
Crown-Breckinridge
or
McKenzie-Pendelton
Refractory Firebrick Liners
(Herringbone Pattern shown, also available
in Running Bond - see Pg.27)
MFP(39,44,49)SHBL- Herringbone
MFP(39,44,49)FRBL- Running Bond
MGFP39/44/49 Appliance Parts ListMGFP39/44/49 Appliance Parts List
ITEM P/N DESCRIPTION QTY
1MFP39-1
MFP44-1
MFP49-1
HEARTH (Left or Right) 2
2MFP39-2
MFP44-2
MFP49-2
REAR WALL 3
3MFP39-3
MFP44-3
MFP49-3
SIDE WALL 7
3A MFP39-3A
MFP44-3A
MFP49-3A
SIDE WALL with 4” opening for Air Kit 1
4MFP39-4
MFP44-4
MFP49-4
SMOKE SHELF (Downdraft Diverter) 1
5MFP39-5
MFP44-5
MFP49-5
DOME REAR - LOWER 1
6A MFP39-6A
MFP44-6A
MFP49-6A
LINTEL FRONT 1
6B MFP39-6B
MFP44-6B
MFP49-6B
LINTEL T-BAR 1
6C MFP39-6C
MFP44-6C
MFP49-6C
LINTEL REAR 1
7MFP39-7
MFP44-7
MFP49-7
DOME SIDE - LOWER 2
8MFP39-8
MFP44-8
MFP49-8
DOME SIDE - UPPER 2
9MFP39-9
MFP44-9
MFP49-9
DOME TOP Ø10” 1
10 MFP39-10
MFP44-10
MFP49-10
DOME FRONT/REAR 2
11 MFP186-1 RATING PLATE 1
12 MFP-DD* 10” DRAFT HOOD 1
14 MFP-211 SMOKE DIVERTER 1
15 MFP-213 SPILL SENSOR SWITCH 1

4
Triple Burner Gas Log SetsTriple Burner Gas Log Sets
MODELS:
MLGB24 24” Natural Gas Burner for the MGFP39
MLGB24P 24” Propane Gas Burner for the MGFP39
MLGL24 24” Log Set for the MGFP39
MLGB30 30” Natural Gas Burner for the MGFP44
MLGB30P 30” Propane Gas Burner for the MGFP44
MLGL30 30” Log Set for the MGFP44
MLGB39 39” Natural Gas Burner for the MGFP49
MLGB39P 39” Propane Gas Burner for the MGFP49
MLGL39 39” Log Set for the MGFP49
SPECIFICATIONS:
These gas burner systems must be installed only in a wood burning replace with the minimum
rebox dimensions and venting requirements met (see table on this page). This appliance is designed
to burn with yellow ames; adequate ventilation is absolutely necessary.
Table 1 - Product Specications
Burner P/N
Dimensions BTU Rating
Included in
Width *
Depth Height
Nat Gas LP Gas
Front Rear † High
Setting
Low
Setting
High
Setting
Low
Setting
MLGB24(P) 35” 25” 15” 17” 65k 21k 50k 22k MGFP39
MLGB30(P) 39” 28” 15” 17” 65k 21k 50k 22k MGFP44
MLGB39(P) 47” 32” 15” 17” 75k 22k 60k 23k MGFP49
* These required widths allow for proper centering of the burner.
† Rear width is at corresponding depth.
Table 2 - Technical Data
Specication Value Qty
Burner system battery type AA Battery 4
Remote transmitter battery type 12V Battery 1

5
Product Overview
Introduction
We extend a warm welcome from all of us at Masonry
Fireplace Industries, Inc. (MFI), proud manufacturers of
Mason-Lite Appliances. Thank you for Choosing MFI.
You may have thought long and hard before you chose the
appliance which would grace your home. Rest assured that
every component of the Appliance has been tested to ensure
long-term durability.
Product Overview
Mason-Lite Appliances are designed as factory-built blocks
to be assembled on-site. These appliances may be installed on
either combustible or non-combustible oors. In order to func-
tion, the system requires a 10” B-vent chimney.
The main components of the Mason-Lite Appliance are:
●Mason-Lite Firebox, Smoke Dome and Refractory Liners
●Gas burner, logs and control system.
●10” Diameter B-vent
Careful step-by-step instructions for each phase of the in-
stallation procedure will be given for the Mason-Lite appliance.
Those instructions generally fall into the following categories:
●Spacing and clearance as it relates to combustible materials
●Familiarity of installation for all components
● The strength of the oor on which it rests
●Chimney system measurements
●Set up and use of the gas burner system.
●Choice of materials and craftsmanship in appliance and
hearth nishing.
Figure 2 - Typical Installations
Internal
Wall
Installation Corner
Installation
Flush
Installation
Full
Projection
Installation
Note that each of these topics will be covered in detail and that
the installer is expected to understand each phase completely
before going on to subsequent instructions.
Attention: Be advised that all the illustrations in this manual
are for general reference only. Do not scale drawings. Actual
design elements will vary from case to case. Pay attention to
specied minimum clearances to combustibles.
WARNING! Under no circumstances should you allow children
to remain unattended while a re is burning in the appliance!
Be sure to keep all objects – furniture, drapes, rugs, etc. at
least 48” (48 inches) away from the opening of the appliance!
Attention: You may need a residential building permit to install
a Mason-Lite Appliance. Consult local jurisdictions before you
get started!
The MASON-LITE gas appliance is not designed to serve as
a primary heat source, rather, the appliance was expressly
created as a supplemental source of heat. This unit is designed
for use with the provided gas burner and approved logs only.
Testing and listing for the MASON-LITE gas appliance has been
undertaken by PFS Test Laboratories, Inc. to ANSI Z21.50.
Under no circumstances should the MASON-LITE gas
appliance be considered for other than in-residence buildings
of conventional construction.
These components make up the MASON-LITE gas appliance
and in the following pages, you will learn how they work
together to create an exceptional unit that will give years of
service and pleasure!
62 1/4"
32"
35"
10" DRAFT
HOOD
11"
4 1/2"
38"
7"
21"
Ø4" OUTSIDE AIR
ACCESS CAN BE
INSTALLED ON
EITHER RIGHT
OR LEFT SIDE
23"
C
A
B
28"
Figure 3
Overall Dimensions MASON-LITE Appliances
Model A B C D
MGFP39 43” 39” 30-1/4” 27-3/4”
MGFP44 48” 44” 35-1/4” 32-3/4”
MGFP49 53” 49” 40-1/4” 37-3/4”

6
Required Gas Pressure
The minimum inlet gas supply pressure for the purpose of
input adjustment is 5” of water column (w.c.) for natural gas.
The maximum inlet gas supply pressure is 10.5” w.c. for
natural gas. The minimum inlet gas supply pressure for the
purpose of input adjustment is 11” of water column (w.c.) for
propane gas. The maximum inlet gas supply pressure is 13”
w.c. for propane gas.
Testing the Gas Supply System
The gas appliance and its required individual shut-o󰀨 valve
must be disconnected from the gas supply piping system
while performing any tests of the piping system at pressures in
excess of 1/2 psig.
The gas appliance must be isolated from the gas supply
piping system by closing its individual manual shut-o󰀨 valve
during any pressure testing of the gas supply piping system at
test pressures equal to or less than 1/2 psig.
This is accomplished by closing the gas supply line valve
required by NFPA 54.
A appliance screen must be replaced after service and be
in place when the appliance is in operation and, unless other
provisions are provided, the screen shall have an opening for
introduction of combustion air.
When glass appliance doors are used, operate the gas
appliance with the doors open. Use only doors rated for this
appliance.
Important
To comply with building code acceptances, and for safe
operation and proper performance of this appliance, use ONLY
MASON-LITE parts and accessories.
Use of other controls, parts, and accessories which are
not designed for use with MASON-LITE gas appliances is
prohibited and will void all warranties, certications, listings,
and building code approvals, and may cause property damage,
personal injury, or loss of life.
The burner included with this gas appliance is non-
convertible and only meant to be used with the gas listed on
the rating plate.
GUIDELINES FOR USE:
All current and future users of Mason-Lite Appliances
are charged with the responsibility for full knowledge of the
information contained within this manual which includes:
• Strict requirements for assembly.
• Detailed instructions for installation.
• Cautionary guidelines for use.
• On-going maintenance instructions.
It is the responsibility of the distributor, subcontractor and/
or the general contractor – whoever shoulders the liability
for installation of this product – to see to it that the work is
in complete compliance with the guidelines and instructions in
this manual.
Note that the general contractor is the party accountable for
seeing that adequate clearances are provided from all rebox
surfaces per specications in this manual.
DONOTUSEAFIREPLACE INSERTOR OTHER PRODUCTS
NOT SPECIFIED FOR USE WITH THIS APPLIANCE.
The Mason-Lite is Designed for Use Only with:
- The supplied burner and log system
- Plumbed LPG or Natural Gas.
DO NOT USE OR STORE GASOLINE OR OTHER
FLAMMABLE LIQUIDS OR GASES IN OR NEAR THE
APPLIANCE!
ATTENTION: A re or an explosion could occur causing
property damage, injury or loss of life if you do not follow the
information in this manual!

7
Clearance to CombustiblesClearance to Combustibles
The distance to be maintained from the surfaces of the
appliance to combustibles must be observed. Below is a list of
the most common combustible materials to name a few:
Drywall Wood ooring Plywood
Sub-ooring Wood Framing Particle board
Mill board Plywood paneling
Maintain the following minimum clearances:
Unit front, sides, rear 0” (0 mm)
Combustible oor (with 1/2” insulation
board under hearth)
0” (0 mm)
Sheathing or trim to opening sides 8” (203 mm)
Combustible sheathing above opening top 8” (203 mm)
Mantel above opening 12” (305 mm)
Opening to side wall 20” (508 mm)
Insulation from rebox 0” (0 mm)
Due to high temperatures, never install this appliance in a
recreational vehicle, in high tra󰀩c areas, drafty areas, or
where curtains, furniture, clothing, or other ammable objects
are less than 36” from the front or side and 42” from the top of
the appliance.
CAUTION: This gas appliance attains high temperatures. Keep
children and adults away from hot surfaces to avoid ignition of
clothing and/or burns. Even after the appliance is shutdown it
will remain hot for a time afterward. Allow the surface to cool
before touching it.
Carefully supervise young children when they are in the room
with the appliance.
All appliance openings for both combustion air and exhaust
must remain open and unobstructed at all times when the
appliance is in operation.
The MASON-LITE appliance has been designed, tested
and approved for zero clearance to combustible oors.
Be certain that the MASON-LITE appliance is installed with
the nished re brick oor of the appliance so that it is at least
4-1/2” (four and a half inches) above the combustible oor
system.
Warning to the structural engineer and/or building contractor:
It is your responsibility to be certain that the appliance can
be properly supported by the combustible oor system on
which the appliance will rest. Be advised that this engineering
equation will be in addition to any live or dead weights that the
oor has to carry.
Mason-Lite Appliance & Chimney SystemsMason-Lite Appliance & Chimney Systems
Before Getting Started…
Even if you consider yourself an expert in the eld of
appliance installation, we at Masonry Fireplace Industries
caution you to take the time to totally familiarize yourself with
the instructions to follow.
We can assure you that there will be information that will
make the installation go smoother and, above all, safer, for
everyone concerned.At the least, reading these procedures will
save you time and, at the most, it will prevent any malfunction
that could result in property damage or serious injury.
Do not start the installation until you have checked out all
the local, regional, state and national rulings, laws and codes
as they apply to appliances and appliance installations. Every
community is di󰀨erent so do not assume that because you
know the requirements for one locality, it will be the same in
the next. Avoid bureaucratic hassles and do your homework
WELL BEFORE you start your project!
1) The MASON-LITE gas appliance is designed to be
installed with a B-vent metal chimney system, UL 103
chimney. Such chimney systems are acceptable where
any traditional masonry replace has been specied.
Note that the chimney system must always vent to the
outside of the building.
2) This Mason-Lite appliance is intended as a supplemental
heat source only. It is not intended as a primary heat source.
3) It is the responsibility of the contractor installer (not the
manufacturer) to ensure that adequate combustion air is
provided for proper function of this appliance. Appliances
take up a large volume of replacement air from outside the
house and if the house is of airtight construction, smoke
spillage may occur if proper draft is not achieved.
4) There are many conditions beyond a manufacturer’s
control when it comes to the operation of the appliance.
The manufacturer cannot be responsible for “smoke free”
operation, nor can the manufacturer take on the responsibility
for problems with surrounding construction; chimneys that
have not been built at the right heights; system drafts
caused by faulty mechanical systems; adverse weather
conditions or any other inclement environmental situations
over which the manufacturer has no control.
5) Inspect all appliance & chimney components for evidence
of damage prior to starting installation. Consult your local
distributor for replacement parts if necessary.
6) Under no circumstances should you make any adjustments
or modications to the chimney system during the
installation procedure. If you do, you are not only liable
for negating the warranty, but you could very well cause a
serious malfunction of the appliance. You must follow these
chimney instructions.
Chimney System Heights
When installed, the maximum overall height of the Appliance is
40’-0” (forty feet). The minimum installed height of the
completed appliance is 14’ 0” (fourteen feet), given that the
chimney is straight. If the chimney includes one or more o󰀨set
sections, the measurement is 17’ 0” (seventeen feet).

8
Supporting Floor Systems
It is the ultimate responsibility of the installer to ensure that
proper concrete slab supports are used.
WARNING to the licensed design professional and/or building
contractor: It is your responsibility to be certain that the Mason-
Lite can be properly supported by the combustible oor system
on which the appliance will rest.
For appliance support foundations installed on concrete refer
to Appendix I and II (pages 31 & 32) for specic instructions.
Rebar locations
Lay-out the position of the appliance and drill holes where
the rebar will be located. Secure the #3 rebar 4 inches into
the concrete foundation with ITW Epoxy or Simpson Epoxy.
Follow manufacturer’s instructions for installation of rebar into
slab.
Wood Floor
Anchorage of appliance to wood oor construction is
required. Refer to Figure 9 for anchorage dimensions. Four
anchors are required to attach to the sub-ooring framing.
Crawl Space or Upper Floor:
For installation of rebox over combustible crawl spaces or
upper oors, anchorage of the rebox is required. Illustrations
of examples of possible anchorage methods are shown in
Figures 4 thru 6 depending upon the type of oor framing. Final
method of anchorage is to be determined by licensed design
professional.
For conventional framing, where the oor joists are parallel
with the sides of the rebox, the addition of oor joists to align
with the anchor brackets allows the brackets to be directly
connected to the oor joists.
Note that additional oor joists may be required to support
the weight of the rebox and chimney. Where the oor joists
run parallel to the front of the rebox, anchorage can be
accomplished in like manner as shown in Figure 4 using
blocking between the oor joist.
For oors supported by I-Joists, the method of anchorage is
illustrated in Figures 5 and 6. Figure 9 illustrates the general
arrangement of anchorage to oor framing.
It is important to take into consideration that the load for
the Mason-Lite Appliance must be considered as additional
dead load that will have to be supported by the oor framing.
Additional oor joists or I-joists may be required as determined
by the licensed design professional.
The dead weights for the appliance are noted in Table I. It
is the task and responsibility of the general contractor/installer
to see that the proper reinforcement for weight loads are
made by a licensed design professional prior to the appliance
installation.
As stated above, it is desirable to place additional framing
for alignment of anchor rods. Refer to Figure 7 for anchor rod
locations.
Figure 4
Floor Sheathing
not shown for
clarity
Metal Base
Assembly
EXAMPLE ONLY
2X FLOOR JOIST
2X FLOOR JOIST
A35 Brackets
(16 required)
I-Joist
Simpson
Strong-Tie
A-35 or
equivalent
Figure 5
I-Joist Anchoring
Top View
Example Only
I-JOISTS
Anchor
Brackets
Figure 6
I-Joist
Anchoring
Bottom
View
Example Only

9
MASON-LITE Weight Determination
The following are dead load weight estimates for the Mason-Lite Appliance.
Table I
Appliance Model MGFP39 MGFP44 MGFP49
Appliance Weight 1,194 lbs. 1,250 lbs. 1,359 lbs.
Mortar, Rebar &
Ready Mix Concrete 350 lbs. 357 lbs. 364 lbs.
Firebrick Lining 333 lbs. 345 lbs. 356 lbs.
Draft Hood 17 lbs. 17 lbs. 17 lbs.
Floor Area 42” x 28” (8.12 ft²) 48” x 28” (9.33 ft²) 53” x 28” (10.30 ft²)
Other Weight Considerations:
1) Appliance nished facing (surround): This information needs to be obtained from the contractor.
2) Weight of metal ue: See chimney manufacturer’s weight specications. Some chimney systems can weigh up to 50 lbs per
lineal foot.
Table II - Deection Limits
Construction L S or W D +L1
Floor Members I/360 --- I/240
1For wood structural members having a moisture content of less than 16 per cent at time of installation and used under dry
conditions, the deection resulting from L + 0.5D is permitted to be substituted for the deection resulting from L + D.
Note that MASON-LITE cannot accept responsibility for structural oor support details. All drawings are presented as mere
illustrations to indicate the presence of the underlying oor system. It is the responsibility of the general contractor/installer to
consult with a local licensed design professional for guidance in building a proper oor support system.
ATTENTION: Figure that these totals for the dead loads are in addition to the actual live load as well as other dead load
requirements for the specied site’s proposed oor. Only the MASON-LITE weights are known. Other weights are estimates and
are subject to material choices of the installer or owner.
F
10"
4"
Figure 7 A
Model A
MGFP39 38-3/4”
MGFP44 43-3/4”
MGFP49 48-3/4”
Figure 8
Fireplace
outline
10”
Typical Anchorage
Layout
EXAMPLE ONLY
SECTION VIEW
ROTATED 90CW
Figure 9

10
What You Will Need
You will nd that the MASON-LITE Appliance is
designed to be completely assembled on-site, consisting of
interlocking precast parts. The parts of the appliance are made
of Mason-Lite’s incredibly strong blend of specialty cement and
a light weight aggregate.
IMPORTANT! When applying mortar, it is imperative that the
concrete blocks be maintained moist (not soaking) so they don’t
absorb the water out of the mortar and cause adhesion to fail.
Frequently run a damp sponge to the parts before mortar is
applied!
The installation of an anchor plate/damper is required but not
supplied. You may purchase it from any chimney manufacturer
or MFI. Also, an optional combustion air inlet MFP4-AK can be
obtained from MFI.
Refractory Firebrick Liners also need to be installed. These
should be a minimum of 1-1/2” thick. The liner will be applied
within the walls and hearth area of the rebox. These are
available from MFI.
Tools needed for installations:
●One 4’ level
●Roto-hammer with ½” drill bit (needed for concrete slab
install only)
●Drill motor with mixer blade (to mix Mason-Lite Mortar)
●Two empty 5 gallon buckets (to mix Mason-Lite Mortar)
●One wheelbarrow and shovel to mix concrete.
●Grout bag
●Triangular masonry trowel
●Rubber hammer
●Sponge and water bucket to wipe down and moisten parts
prior to applying mortar.
Materials needed for concrete slab installations
MGFP39:
Six (6) pieces 3/8” rebar x 36” long (included with unit)
Six (6) pieces of rebar x 12” long (included with unit)
MGFP44/49:
Eight (8) pieces 3/8” rebar x 36” long (included with unit)
Eight (8) pieces of rebar x 12” long (included with unit)
ALL UNITS:
●Epoxy for securing rebar in footing / foundation.
●Three (3) - 90 lb. bags of Ready-Mix Concrete with 1/4” or
smaller aggregate.
Materials needed for wood floor installations
MGFP39:
Six (6) pieces 3/8” rebar x 36” long (included with unit)
Six (6) ea. All-thread x 12” long (with nuts and washers)
MGFP-44/49:
Eight (8) pieces 3/8” rebar x 36” long (included with unit)
Eight (8) ea. All-thread x 12” long (with nuts and washers)
ALL UNITS:
Three (3) - 90 lb. bags of ready mix concrete with 1/4” or smaller
aggregate.
SURFACE CRACKS - The MASON-LITE FIRE-PLACES are
manufactured using high quality materials. During the
drying process, surface cracking may occur. These small
cracks (under 1/16” will not aect the appliance safety or
performance). During the assembly process, ll surface
cracks with thin-set mortar and brush when drying for a
smooth surface nish.
Field Assembly Procedures
a) Mixing the MASON-LITE mortar – The mortar comes
premixed and should be dry. Be sure to use clean water and
work it up into a mixture that is pasty but not lumpy. If it’s too
thin and the surfaces don’t stay moist, the components will
not adhere. Load the mixture into a standard grout bag.
b) Apply about ½” (one-half inch) thread of mortar. The mortar
bead should be approximately ½” (one-half inch) away from
all edges. The mortar has a considerable amount of holding
power so do not overload the components with too much
mortar. Keep the components moist at all times!
c) Some mortar will “ooze out” when placing components
together, this is normal. Wipe excess away with a trowel. Do
not cover component surfaces completely with mortar. Do
not apply the mortar in thick bands even if the component
you are working with is larger than the rest. You will want to
apply “stripes” of mortar in these situations.
d) Make sure components are level. It’s extremely important
that you pay careful attention to how you are assembling
the Mason-Lite Appliance since every component builds on
the next. If you have to make any kind of an adjustment, do
not try to do it “by loading an opening” with mortar, this will
only result in a appliance that will not be plumb or level.
Use wood shims instead. You will nd these small wood
shims supplied with the Mason-Lite Appliance and
you can nudge them in between openings to achieve the
precision you need in making component adjustments.
Once you have removed any shims, you will want to cover
any gaps that may have resulted with the mortar.

11
Appliance Assembly ProceduresAppliance Assembly Procedures
1. Place the Mason-Lite appliance hearth on the oor where
the appliance is to be installed. For concrete slabs,
supporting oor needs to be rated at ASTM 90.
2. Draw an outline of the hearth area based on the dimensions
shown in Figure 10. Position Hearth slabs and mark rebar
center locations. Drill 4 inches into concrete slab and secure
the 8 pieces of 12 inch rebar with epoxy. For other than
concrete slabs, draw an outline of the hearth area based on
the dimensions in Figure 9 taking special consideration on
the position of where the all-thread studs will be located in
relation to the anchoring locations. All-thread rods should
stick up through the holes on the hearth slabs.
Figure 10
Model W
MGFP-39 43”
MGFP-44 48”
MGFP-49 53”
W
28”
Apply mortar
between joints
Left Side Hearth 2nd
Right Side Hearth 1st
12 inch rebar
3. Mix a batch of mortar and prepare Right Side Hearth bottom
surface to be bonded as shown in Figure 11.
4. Align Right Side Hearth to the outline created. The overall
width should allow for an approximate gap of 1/8” between
slabs for the additional mortar to unite the remaining slab.
Check for surface atness, level if necessary.
Figure 11
1/2” away
from edges
1/2” mortar
bead (typical)
Hearth section shown prepared
for Right Side position
Apply mortar bead to
all mating surfaces.
5. Apply mortar to the remaining Hearth except this time
apply beading on surface to be facing oor as shown in
Figure 12.
Figure 12 Hearth shown prepared
for Left Side position
6. Before installing side walls, conrm placement of outside
combustion air access (if required), this can be installed
either side depending on which side is accessible to outside
combustion air (all diagrams in this manual show the
combustion air inlet hole on the right side). Prepare side
wall and rear wall mating surfaces with the prepared mortar
and begin assembly.
Figure 13 Side Wall shown prepared for Right
Side Air Access.
For Left Side, bead opposite side.
1/2” AWAY
FROM EDGES
7. Keep the assembly of the next sections of the rebox side
walls moving up, keeping components moist, mixing mortar
as you need it and threading the mortar appropriately as
you stack each section, one onto the next. Constantly check
for squareness and levelness while building each course of
block. As you complete each section, make certain that you
adhere the mortar at each and every joint.
Figure 14
Combustion Air Access
Right or Left (Right shown).
Apply
mortar
Apply mortar
Side Wall
Rear Wall
Side Wall

12
8. Install Downdraft Diverter and nal row of Side Walls
(Figure 15). Then place #3 rebar (8 each, 36 inch long)
vertically through the cells until they reach bottom. Position
them adjacent to the rebar or all-thread sticking up from the
hearth.
9. All components must be level. Mix approx. 2 cu. ft. of Ready-
Mix Concrete. Fill all cells with Ready-Mix Concrete mix.
Figure 15 Downdraft
Diverter
12 inch
rebar or
all-thread
10. Set the Lintel and Lower Rear Dome as shown in Figure
16. Check that all is level. If adjustments are needed, use
shims and ll gaps with an appropriate amount of mortar.
Note: Although you are cautioned to use MASON-LITE
mortar sparingly because it does have such holding power,
you should look over the rebox assembly at the end and ll
in any gaps, especially joint connections, with the mortar.
Figure 16
Lintel
T-Bar
Lower Rear
Dome
Important: Adjustments can only be made while the mortar
is still wet when correcting for squareness and leveling.
11. Assemble Lower Dome Sides as shown in Figure 17. The
beveled face lines up with the inward angles of the lintel
sides. Resulting top surfaces should be level.
Figure 17 Lower Dome Sides (Rating
Plate faces inside)
12. Verify that the smoke dome side, front and rear walls are
aligning correctly and that the surfaces are smooth and
uniform. Make sure connections are covered with an
adequate amount of mortar. Remember that you have
the option of using shims but they must be removed and
any holes lled. Make any adjustments to the appliance
alignment before continuing to the next step.
13. Assemble Upper Dome and Dome Sides as shown in
Figure 18. Check your assembly here. If things are
proceeding as they should be, the nished top surface
should be at and level.
Figure 18 Upper Dome Sides
Upper Dome
Front/Rear
14. Finally, set the Dome Top into position. Be sure that it is
ush in every direction as you place it on the crest of the
smoke dome wall assembly. After this is done, proceed to
section on “Installing Damper and Chimney System”.
Note: The chimney hole on the Dome Top is not centered from
front to back - it should be o󰀨set closest to the rear of the
appliance (see Figure 19).
Figure 19 Center of chimney hole is
o󰀨set towards the rear.
10”
12-1/2”
MGFP-39/44/49

13
Mason-Lite Firebrick Liner
The rebrick lining is not supplied as part of your Mason-Lite
appliance but can be purchased from MFI. They are available
in split herringbone and full running bond patterns. (see Figures
20 and 21)
You also have the option to have custom rebrick installed,
but it must be at least 1-1/2” thick.
Before you install the lining, you will need to drill all the
required gas and electrical line feeds and the combustion air
supply access holes.
Disclaimer: Masonry Fireplaces Industries cannot be held
liable for the way rebrick or rebrick mortar performs. It is
not unusual for heat stress cracks to appear on the rebrick or
rebrick mortar during the life of the appliance.
Figure 20
Figure 21
Appliance Finishes & Combustible Trim Clearances
1. Mantel and Mantel Shelf Clearances – As with any radiant
heat appliances, all Mason-Lite Appliances must comply
with building code safety clearances, per units that have
openings of 6 sq. ft. (six square feet) or greater. You must
keep combustibles such as trim 8” away from the rebox
opening (for mantel clearances, see Figure 22).
Combustible material
Figure 22 Shelf or trim
safe zone
12”
1”
8”
3”
1.5”
Distances to underside
of shelf or trim
Upper
appliance
area
Mantel and side clearances
Attention: The manufacturer suggests that when building
out a appliance, that the owner and installer opt for complete
safety. MFI, therefore, advises that combustible mantel
shelves feature clearances that are more than the 12”
(twelve inch) minimum equal to the projection of the shelf.
As a guide, gure that a 10” (ten inch) wide shelf should be
20” (twenty inches) above the appliance opening.
2. Walls That Adjoin – Safety codes and all practical outlooks
insist that your appliance cannot be installed closer than
2 ft. (two feet) to any walls in the room the appliance is
housed in or to any walls of adjoining rooms.
3. Caution in Regards to Combustibles – If any part of the
appliance or objects in the room (curtains, rugs, paint,
cushions, etc.) start to show warping or discoloration due to
heat from the appliance, it is time to take immediate action.
Each installation requires a di󰀨erent set of circumstances
to deal with the problem, but one thing is certain: do
not use the appliance until you have gured out how to
address the problem. You are facing a potential re hazard.
The manufacturer of the MASON-LITE gas appliance
cannot be responsible for the make-up of material on the
exterior of the appliance you have chosen, nor can MFI
be held responsible for the materials in a room that may
be responding negatively to heat. However, in almost all
cases, there is a solution to the problem, either by making
adjustments to airow or the room itself.
Installing Outside Air
1. Be mindful that outside, fresh air is not required for the
operation of the Mason-Lite Appliance. However, local
building codes may require combustion air and it is an
excellent choice in some situations, especially in weather
conditions where homes are very well insulated and tightly
sealed. Check local building codes for specic requirements.
2. Install Outside Air Kit - MFP4-AK into the Mason-Lite
Firebox either through the side wall opening provided. The
tubing that goes out of the rebox wall must feed into a

14
exible metal conduit as the source for outside combustible
air. It can go straight out through an outside wall or into a
ventilated crawl space. If crawl space is used, check codes
for proper termination.
3. Be sure that you carefully check the source of the outside
air before you choose the site for your air intake. You don’t
want a place where snow will collect, where bushes or trees
will be growing or a location that is too close to any other
structure.
4. The suggested maximum height for the air intake tubing
is 50 ft. (fty feet) above the hearth. That height is if the
intake nishes o󰀨 at a minimum of 3 ft. (three feet) below
the chimney cap level.
5. Install a screened termination cap to keep out animals.
Mason-Lite Chimney Systems
Overview
This Mason-Lite gas appliance may be installed with an
approved 10” B-vent chimney system. A metal chimney adapter
is required to attach the chimney to the top of the rebox. This
can be purchased from FMI: part number MFP-DD.
Installers are cautioned to put the chimney system together
exactly as instructed and shown in chimney manufacturer’s
guide. Any variations may have serious consequences resulting
in an accident or malfunction. If instructions are not followed,
the warranty on the product will become null and void.
Note that the most important aspect of the installation is the
maintenance of minimum required clearances to combustible
materials. Those specic installation requirements must
be followed with great precision as you are dealing with the
potential of re hazard if the correct combustible limit is not met
and maintained. When you look at the drawings provided in this
section, you will see that actual installations may vary due to
individual design preferences. That is to be expected.
Design and framing specics may vary from the drawing
to installationy. Clearances to combustibles is a stringent
requirement.
WARNING:
If you do not use chimney manufacturer’s parts and/or if you
do not follow exact instructions for installation of chimney
components, you may be responsible for appliance malfunction,
an accident or a re hazard.
Attention: Be advised that your choice of Chimney System
meets the following standards and requirements:
●Designed for installation in accordance with National Fire
Protection Standard
● Meets requirements of NFPA 211
●Designed in accordance with BOCA Basic National Codes
●Meets Uniform Building Codes.
General Chimney Requirements for Height and Clearance
When installed, the maximum overall height of the chimney
system from bottom of appliance to the top/termination chimney
is 40 feet. The minimum installed height of the completed
Chimney System is 14 feet with a straight ue stack, 17 feet if
the chimney includes one or two o󰀨set sections.
Throughout the length of the chimney – along the outer
periphery of the ue you must have at least 1” (one inch) of
clearance all around the circumference. When the chimney is
passing through a living space, it must be completely closed o󰀨.
A “live” chimney is never allowed to be within reach of humans;
the chimney must be completely designed to be hidden from
view and protected, away from human interaction.
Note that it is acceptable for the chimney’s restop space and
roof ashing to come in direct contact with common construction
materials, such as drywall, ooring, paneling, plywood, millboard,
particle board and a variety of normal framing materials. Always
follow the specic installation requirements of your selected
chimney manufacturer.
Determining Finished Height for Appliance
Overview
Figuring out the exact height of the Mason-Lite Appliance you
are about to install is relatively easy if you follow a few simple
steps. It is a matter of determining the number of chimney
sections and the chimney components that will be required for
the installation. Bear in mind that the minimum height of the
MASON-LITE once installed is 14’0” (fourteen feet) and that it
is higher if o󰀨sets are used. Here is how to calculate the height
of the completed appliance:
1. First, ascertain the height of the chimney. This includes the
distance from the very top of the smoke dome to where the
top of the ue ends. That is where the smoke leaves the
ue.
2. Aside from the chimney sections, include all the components
that you will be using in your installation - anchor plate
damper, restop spacers, stabilizers, and o󰀨sets.
3. Create a Component Height Chart by measuring each
component and completing the following:
Anchor Plate = 4 ”
Firestop Spacers = _ _ _ _ _ _
Support box = _ _ _ _ _ _
Stabilizers = _ _ _ _ _ _
O󰀨sets = _ _ _ _ _ _
Pipe Sections = _ _ _ _ _ _
(Stabilizer – Must be present on vertical chimneys every
30 feet and on o󰀨set chimneys every 10 feet.)
4. Take the total height of every component that will be
included in your installation and then subtract that from the
desired total height you wish the nished appliance system
to be.
5. You will need to refer to the chimney manufacturer’s
information in order to gure out the available lengths and
the quantity of the sections that you will need.

15
The Special Case of O󰀨set Installation
Overview
Special, detailed installation instructions must be given for the
proper handling of o󰀨setting for the chimney system. Maximum
o󰀨set is 30 degrees o󰀨 of vertical and there should be no
more than one o󰀨set sequence per chimney system. Under no
circumstances should two o󰀨sets be attached to comprise a
60 degree o󰀨set conguration. Always maintain at least 2” (two
inches) of clearance around all o󰀨set installation for air space
and necessary clearance from combustibles.
Working with Floors and Ceilings
It is quite probable that when your installation must pass through
a oor or ceiling, you will have to opt for a 30 degree angle in
which case you are advised to use a restop spacer. Should
the length of the chimney below the oor or ceiling be less than
10’ (ten feet), support the chimney at the juncture of the oor/
ceiling with a stabilizer. As in all phases of chimney component
installation, you will want to be sure you are making allowances
at every juncture for the 2” (two inch) clearance space from
combustibles.
Background Information on O󰀨set Installation
1. When obstructions are present, it will be necessary to
o󰀨set sections of the chimney using the 30 degree o󰀨set
component and, for every o󰀨set component, two elbow
components.
One elbow begins the installation procedure and the second
elbow is used to nish o󰀨 each section. In all likelihood, a 30
degree o󰀨set elbow will probably be the rst hardware used o󰀨
the top of the anchor plate damper.
Note: Under no circumstances should you use an o󰀨set
elbow in place of a return elbow. They have distinct purposes
in the conguration of the o󰀨set installation and they cannot
be interchanged, part for part.
2. Depending on the conguration you are contending with,
you may either attach the elbows and o󰀨set piping together
or you may need to insert sections of the vertical chimney.
Whatever the scenario, you cannot allow sections of the
chimney to measure more than 20’ (twenty feet) between
the elbows.
3. Assuming you have sections of vertical pipe that are more
than 10’ (ten feet) measuring between elbows, you must
insert – at midpoint – a chimney stabilizer. When installing
the stabilizer, pull out the support straps with a good amount
of tension and hammer to the frame.
4. If your o󰀨set sections go over 6’ (six feet) in length, you
will need to give added support using a sheet metal screw
– a # 8 x ½” is recommended. The screw will be fastened
underneath the joint.
5. To ensure a tight t for the screw, drill a hole that is 1/8”
(one-eighth inch) in diameter right at the chimney joint’s
underside. Be sure that you position the drill at the very
center of where the joint overlaps. Be very careful not to
drill through the inner casting; drill only through the outer
chimney.
Installing Vent Plate and Chimney System
Before installing your B-Vent to the Mason-Lite Firebox you
must install a steel vent plate. The vent plate mudt be installed
in the vertical (open) position on the outside of the vent pipe
and is designed to close-o󰀨 the chimney in the event the pipe
is removed or fails, thus alerting the operator of a problem.
Next, attach the masonry anchor plate (supplied). The
anchor plate is pre-drilled with holes for four (4) cement wedge-
anchors.
1. Place the plate and mark the top of the rebox. Then remove
the plate to carefully pre-drill holes for the wedge anchors.
2. Using the supplied vent plate, apply a 1/4” (one quarter
inch) bead of gasket cement around the base damper lead
pipe. Apply ceramic rope gasket on to the gasket cement.
3. Apply balance of gasket cement in a 1/4” (one quarter
inch) bead on top of smoke dome top approx. 3” (3 inches)
outside of outlet hole. Install damper on top of unit pressing
damper into cement. Attach using four (4) #8 cement
wedge-anchors.
Figure 23
Vent Plate Installation
Attention: Clearance to combustible construction can not be
reduced during course of construction. For the safe operation
of the nished appliance, these clearances must be followed
when building the framework to house the chimney system.
Installing the valve/control box assembly
1. Fasten the valve/control box assembly to a stud such that
the control switch is facing in the desired direction and
ush with the future location of the nished wall or other
enclosure.
2. Install the two ‘D’ batteries into the battery holder within the
control box.
3. Run the wires for the spill switch through the small hole
in the upper wall. Important: This control box must remain
accessible and removable for service after installation.

16
A “B-type” venting system must be connected to the
appliance for venting to outside of building. The following
section is provided as a guide to a standard B-type vent
installation.
Standing codes requirements concerning B-type vent
installations may vary within your state, province or local codes
jurisdiction. Therefore, it is recommended that you check with
your local building codes for specic requirements or in absence
of local codes, follow Section 7.0 of the current National Fuel
Gas Code ANSI Z223.1/NFPA 54 for Category I systems using
double wall B-1 vent pipe.
This gas appliance must be vented to the outdoors only
and may not be terminated into an attic space or into a chimney
ue servicing a solid fuel burning appliance.
This appliance may be vented through a manufactured
chimney system or a masonry chimney using a B-vent adapter
or a chimney liner system if the system is listed, inspected
and approved by local codes and/or building authorities.
The examples shown in Fig. 24 are typical of most B-vent
installations and codes practices.
Example 1: Shows the minimum allowable system height and
lateral o󰀨set for an inclination of 60° or greater.
Code species that o󰀨sets of 60° or greater are considered
horizontal and must follow the 75% rule for lateral to total
vertical system height.
Codes also allows only one o󰀨set in the total system when
at 60° or greater.
The total vertical height in this example represents the
minimum height of 8 ft. and therefore the allowable lateral is 6
ft. when the 75% rule applies.
If the lateral length must exceed 75% then the system must
be sized in accordance with the Category I venting tables.
Example 2: Shows a multiple o󰀨set each at a 45° inclination.
Multiple o󰀨sets are permitted if they do not exceed a 45°
inclination. The total lengths of the two o󰀨sets are not required
to meet the 75% allowable rule.
Example 3: Shows a single o󰀨set at 45° of inclination and
therefore the lateral length at 10 ft. of o󰀨set does not have to
meet the 75% rule.
In each case the o󰀨sets must be supported and restops
must be positioned wherever the vent must pass through a
sub-oor, ceiling joist or an attic overhang.
The vent pipe must terminate vertically into a listed type
vent cap and extend a su󰀩cient height through an approved
roof ashing, roof jack or a roof thimble. At all points the listed
clearances must be maintained.
Vent terminations must be located in accordance with
height and proximity rules of NFPA No. 54.
These rules apply to vents at 12” diameter or less and
require a minimum height in accordance with the roof pitch and
a minimum of 8 ft. distance from a vertical wall or obstruction
(see Fig. 25).
If venting horizontally through a side wall becomes
necessary, a listed thimble approved for use with B-type vent
must be used. Check with your local codes before venting
through a side wall.
Some codes areas allow the use of existing B-type vent
systems if the system is at or above the recommended diameter
of the ue.
The ue connection must be made using listed B-type
connectors and the existing system must be code inspected
for damage and proper installation.
It is not recommended that this appliance be common
vented with an existing gas burning appliance. However, if it
becomes necessary to common vent this appliance, the venting
system must be sized and congured in accordance with the
common venting guides Appendix G of the current National
Fuel Gas Code NFPA No. 54/ANSI Z223.1.
Note: Before connecting this appliance to an existing vent
system or a common venting system, consult with your local
architect, planner, or building o󰀩cial.
Venting InstallationVenting Installation
Figure 24

17
Specifying Chimney HeightsSpecifying Chimney Heights
If the horizontal distance from the mid-point of the chimney
to the peak of the roof ridge is less than 10 feet, the top of the
chimney must be at least 2 feet above the roof ridge. This is
called the “2 foot in 10 foot” rule.
If the horizontal distance from the chimney’s center
measured across to the ridge of the roof is more than 10 feet,
the top of the chimney still needs to be at least 2 feet above a
point measured from a distance of 10 feet horizontally along
the roof.
Though there are many congurations in meeting these
requirements, chimney height cannot be less than 3 feet above
the roof at the edge of the chimney.
If the roof is at, the chimney must extend no less than 3
feet from where it intersects the roof. If the chimney is entering
the roof at an angle, measure the shorter angle where the
chimney intersects the roof which should be at least 3 feet.
Note: The previous guidelines do not take into consideration
outside conditions which may require a higher chimney due
to foliage, other buildings, power lines and weather conditions
in your area. Follow the chimney manufacturer’s installation
guide for further information.
Figure 25
Chimney Termination UnitsChimney Termination Units
You will be installing at or possibly near the top of the
chimney chase ashing. A top termination unit is the essential
piece of equipment in keeping sparks out of the atmosphere.
Before installing this important piece of equipment, you
will have to make a judgment call as to whether or not the
termination unit – like all the other exterior exposed chimney
components, for that matter – should be painted in order to
protect it/them from rusting and weathering. Particularly if you
are installing the appliance and chimney near water or in a high
humidity area, the manufacturer recommends a top quality,
rust-proof paint especially formulated for metal. Follow the
paint manufacturer’s directions, applying the paint well before
you are scheduled to install the round top termination unit or
any of the ashings or ues that will be exposed to outside
weather conditions.
Venting terminals shall not be recessed into walls or siding.
This appliance, when installed, must be electrically grounded
in accordance with local codes and in the absence of local
codes, with the National Electrical Code, ANSI NFPA 70, or the
Canadian Electrical Code, CSA C22.1.
Important Pre-installation InformationImportant Pre-installation Information
Before you begin, review the information and safeguards
below regarding the installation and operation of the gas
Appliance.
This appliance may only be connected to the gas
supply listed on the label. Never use propane gas in a gas
appliance designed for natural gas or natural gas in a gas
appliance designed for use with propane gas.
The gas appliance must be installed by an MFI Certied or
other qualied professional installer. The installation, including
provisions for combustion and ventilation air, must conform
with local codes, or, in the absence of local codes, with the
latest edition of the National Fuel Gas Code, ANSI Z223.1, and
NFPA54.
Keep the appliance area clear and free from combustible
materials, gasoline, and other ammable vapors and liquids.
The appliance must have a gas supply line that has been
installed by a qualied technician in accordance with all local
codes.
The gas supply line must be 1/2” minimum interior diameter. If
the gas line to the appliance is longer than 5’, a larger diameter
line may be necessary.
Burner P/N BTU*
(x 1000)
Orice Drill
Size (top/front) Included in
Nat LP
MLGB24 (N) (P) 60 28/48 47/56 MGFP39
MLGB30 (N) (P) 90 19/41 MGFP44
MLGB39 (N) (P) 84 40/55 MGFP49
*Nominal BTU based on gas inlet pressure. Nominal gas inlet
pressure for natural gas is 5” W.C.

18
Installing Spill Switch and Ba󰀪e assembly
1. Connect the blade connectors on the spill switch wires to
the matching wires from the valve/ control box assembly
coming through the upper hole in the rebox.
2. Center the Smoke Shelf with the spill switch sensor closest
to the front of the appliance.
3. Use six (6) Tapcon screws to fasten the Smoke Shelf in
place as shown in Figure 26.
4. Seal any remaining gaps with high temp silicone (Figure
27).
Important: This ba󰀪e assembly and only this the supplied
assembly (with spill switch) must be properly installed for
the safe operation of this gas appliance.
1/2"
2"
Ø1/2"
Figure 26
Smoke
Shelf
Spill
Switch
Lintel
Tapcon
Screws
1/2"
2"
Ø1/2"
Figure 27
Seal gaps with
hi-temp silicone
GND
TR
MV/PV
MV
E3
SENSE
PV
TH
IGN
120V
AC
24V AC
TRANSFORMER
THERMOSTAT
TGRAY
IGNITION
CONTROL
MODULE
Figure 28 Spill sensor wires to valve/control box
Spill Sensor
wires from
Smoke Shelf
Owner’s Operation & Precautions
Installers of the Mason-Lite are urged to call the attention of
appliance owners to the following precautions. The installer
should hand-deliver this owner’s manual to the owner or leave
behind with the unit after the installation is complete.
Warning: Use only the included appliance grate or manufacturer
approved replacement.
Warning: Do not attempt to operate your appliance without a
re safety screen installed.
CAUTION: Use only the logs that come with this gas appliance.
The manufacturer cautions against using chemical chimney
cleaners. Never burn solid fuel in this appliance under any
circumstance.
1. First Lighting of the Mason-Lite – After construction is
completed, all elements of the appliance and chimney
system must be completely dry. This means that the unit
must stand without any ring for a minimum of 28 days.
Only after that period of time can a rst lighting take place.
Do not let the re burn for more than one hour. After this rst
lighting – when the appliance has started to “cure” Do not
set another re for at least 24 hours.
2. Second Lighting – With the second lighting you can let the
re burn two hours – no more.
3. After First and Second Lighting – When the appliance has
been properly cured with careful “maiden” rings, you will
be able to run the burner for as long as you like.
Attaching the Burner and the Grate
1. Unpack the burner assembly and place the rear legs of the
burner into the brackets in the back of the rebox.
2. Thread the pilot lines from the burner pilot assembly and
through the hole in the lower side of the rewall to the valve/
control box assembly and attach to the valve.
3. Connect the supplied ex connector from the output of the
valve, through the hole and to the burner.
4. Connect the second ex connector from the input of the
valve to the gas stub down stream from the required
manual shut-o󰀨 valve.
5. Insert a one-way screw into the hole in the front of each
bracket and tighten with a long (min. 12”) screw driver
until contact is made with the grate leg and the grate is
permanently locked in place.
IMPORTANT: Once installed the burner cannot be
removed.
6. Fill in the holes you have drilled around the gas piping with
the regular MASON-LITE mortar.
Note: The required 1/8” NPT up stream pressure tap is built
into the valve (Figure 33).
CAUTION: CHECK ALL CONNECTIONS FOR GAS LEAKS
USING A HALF-AND-HALF SOAPY WATER SOLUTION.
IF A LEAK IS DETECTED TIGHTEN CONNECTIONS AND
TEST AGAIN.
NEVER USE AN OPEN FLAME TO CHECK FOR GAS LEAKS.

19
Placing the Logs
1. Place the back bottom log on the grate behind the top burner
and as far forward (against the top burner) as possible
without touching the pilot. The at side should be down and
the heat chambers facing the back of the appliance (Figure
35).
2. Place the front log on the grate in front of the top burner
pipe with the at down and the heat chambers toward the
burner pipe and the log as far forward as possible while
keeping the back parallel with the burner pipe (Figure 36).
3. Place top logs across the front and back logs in the order
and positions shown in Figure 40.
WARNING
Failure to position the parts in
accordance with these diagrams or
failure to use only parts specically
approved with this appliance may result
in property damage or personal injury.
FOR YOUR SAFETY, READ BEFORE LIGHTING
Do not use this gas appliance if any part has been underwater.
Immediately call for a qualied professional service technician
to inspect the appliance and to replace any part of the control
system and any gas control which has been under water.
The Mason-lite burner system has a pilot which can be lit by
hand using a match or lighter. When lighting the pilot, follow
these instructions exactly.
BEFORE LIGHTING, smell all around the burner area for gas.
Be sure to smell next to the oor as some gas is heavier than
air and will settle on the oor. IF YOU SMELL GAS, FOLLOW
THE INSTRUCTIONS ON THE COVER (P. 1).
TO LIGHT THE APPLIANCE WITH THE WALL
SWITCH
Move the ON-REMOTE-OFF wall switch to the ON position
(Figure 41). This transmits a rapid series of sparks at the pilot
head and will ignite the gas.
TO SHUT DOWN THE GAS APPLIANCE USING THE WALL
SWITCH
Move the switch to the OFF position (Figure 41). The gas ow
will cease, and all ames (main burner and pilot) will go out (see
important note below).
OPERATING THE BURNER USING THE REMOTE
Move the wall switch to the REMOTE position and follow the
instructions included in the remote kit for lighting and shutting
down the attached burner.
IMPORTANT: Do not allow the appliance opening to be
blocked in any way while operating the appliance. The
appliance may be operated with a Mason-Lite screen installed
and drawn.
OOUUTTIINN
PPIILLOOTT
IINN
Figure 41
Upstream gas
pressure tap
MAINTAINING THE PILOT
Your gas appliance is equipped with a safety pilot that will shut
o󰀨 the gas supply in case the pilot is not burning or functioning
properly. Regularly verify that the pilot is adjusted properly with
the pilot ame hitting the electrodes as shown in Figure 42. If
the pilot will not stay lit, call your local gas utility or gas supplier.
TO CHECK UPSTREAM GAS PRESSURE
Unscrew the four (4) screws above and below the control panel
face, then pull the control panel out far enough to expose the
test ports on the valve (Figure 41). Unscrew the port marked IN
part way and test.
CAUTION: Do not kink the ex connectors coming from the
valve while accessing it.
Note: Pilot ame should encircle top of electrodes.
See instructions cover for example of proper main burner ame
pattern.