Monessen Hearth VENT-FREE DIS33G User manual

This is an unvented gas-fired heater.
It uses air (oxygen) from the room
in which it is installed. Provisions for
adequate combustion and ventilation
air must be provided. See page 9.
READ AND SAVE THESE INSTRUCTIONS
WARNINGS
If the information in this manual is not followed
exactly, a fire or explosion may result causing
property damage, personal injury or loss of life.
– Do not store or use gasoline or other flammable
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. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call the
fire department.
– Installation and service must be performed by
a qualified installer, service agency or the gas
supplier.
MODEL: DIS33G
Natural Gas or Propane/LPG
Control Type: Milli-Volt and T-Stat
VENT-FREE
FIREPLACE SYSTEMS
INSTALLATION AND
OPERATING INSTRUCTIONS
WARNINGS

2 23D8020
CONTENTS
Important Safety Information ..................................3
Product Features......................................................5
Operation..............................................................5
Natural Gas ..........................................................6
Propane/LPG........................................................6
Specifications...........................................................6
Ignition Controls....................................................6
Pilot.......................................................................6
Thermal Generator ...................................................6
Getting Started..........................................................7
General Installation Information .............................8
Removing Screen.................................................8
Installing Canopy..................................................8
Codes...................................................................9
Adequate combustion and Ventilation Air.............9
Clearances and Height Requirements..................11
Fireplace Framing...................................................14
Securing Heater to Floor........................................15
Connecting the Gas................................................16
Checking Gas Pressure.........................................18
Electrical Wiring (Milli-Volt) ...................................19
Electrical Wiring (Fan)............................................21
Log Placement........................................................22
Flame Appearance..................................................26
Checking the Burner Flame...................................27
Operating Instructions...........................................28
What to Do if You Smell Gas..............................28
Milli-Volt Control Lighting Instructions.................29
Match Lighting Instructions.................................30
Cleaning and Servicing..........................................31
Troubleshooting .....................................................32
Illustrated Parts Breakdown..................................34
Fireplace Assembly ...........................................34
Grate and Base Assembly .................................36
Logs....................................................................38
Warranty..................................................Back Cover

23D8020 3
9. The installation must conform with local codes or, in
the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.l/NFPA54.
10. This unit complies with ANSI Z21.11. Unvented Heat-
ers.
11.Do not install the heaters in a bathroom or bedroom.
12.Correct installation of the ceramic fiber logs, proper
location of the heater, and annual cleaning are neces-
sary to avoid potential problems with sooting. Sooting,
resulting from improper installation or operation, can
settle on surfaces outside the fireplace. See log place-
ment 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. Ceiling fans may
create drafts that alter burner flame patterns. Sooting
and improper burning will occur.
14.Caution: Candles, incense, oil lamps, etc. produce com-
bustion 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 appli-
ance is in operation.
15.This is an unvented gas-fired heater. It uses air (oxygen)
from the room in which it is installed. Provisions for
adequate combustion and ventilation air must be pro-
vided. See page 9.
INSTALLER
Please leave these instructions with the appliance.
OWNER
Please retain these instructions for future reference .
IMPORTANT
Read these instructions carefully before installing or trying to operate this vent-free gas heater.
IMPORTANT SAFETY INFORMATION
8. CARBON MONOXIDE POISONING: 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 ser-
viced as it may not be operating properly.
Continued on page 4
• Any change to this heater or its controls can be dangerous.
• Improper installation or use of the heater can cause serious injury or death from fire,
burns, explosion or carbon monoxide poisoning.
• Do not allow fans to blow directly into the fireplace. Avoid drafts that alter burner
flame patterns.
• Do not use a blower insert, heat exchanger insert or other accessory, not approved
for use with this heater where applicable.
WARNING
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 appliance.
4. Do not place clothing or other flammable material
on or near the appliance.
5. Any safety screen or guard removed for servicing
an appliance, must be replaced prior to operating the
heater.
6. Installation and repair should be done by a quali-
fied service person.
7. To prevent malfunction and/or sooting, an unvented
gas heater should be cleaned before use and at least
annually by a professional service person. More fre-
quent cleaning may be required due to excessive lint
from carpeting, bedding materials, etc. It is imperative
that control compartments, burners and circulating air
passageways be kept clean.

4 23D8020
IMPORTANT SAFETY INFORMATION
Continued from page 3
16.Keep room area clear and free from combustible materi-
als, gasoline and other flammable vapors and liquids.
17.Unvented gas heaters are a supplemental zone heater. They
are not intended to be the primary heating 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, addi-
tional 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 annoying smoke and smells as they are
burned off during the initial operation of the appliance;
possibly causing 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 percent 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 provisions for combustion
air are provided, the screen must have an opening(s) for
induction of combustion air.
THIS APPLIANCE MAY BE INSTALLED
IN AN AFTERMARKET, PERMANENTLY
LOCATED, MANUFACTURED (MOBILE)
HOME, WHERE NOT PROHIBITED BY
LOCAL CODES.
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.
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.
Never connect unit to private (non-
utility) gaswells. Thisgas iscommonly
known as wellhead gas.
WARNING

23D8020 5
Your vent-free fireplace must be mounted to the floor or the fireplace hearth.
OPERATION
This unvented gas heater requires no outside venting and burns cleanly with high heating efficiency.
Piezo Ignitor
Fireplace
Screen
Control Knobs
PRODUCT FEATURES
Optional
Face Plate
Figure 1 - Unvented Gas Heater with Control Access Door Open
On/Off Switch
Blower
Optional T-stat
Sensor

6 23D8020
NATURAL GAS
Milli-Volt and T-Stat Pressure
Regulator Pressure Setting: 3.5" w.c.
Pilot Regulator: 3.5" w.c.
Gas Inlet Pressure: Max. 10 1/2" w. c.
Min. 5" w.c.
PRODUCT FEATURES AND SPECIFICATIONS
PROPANE/LPG
Note: An external regulator is required to reduce supply pressure to a maximum of 13" w.c.
Milli-Volt and T-Stat Pressure
Regulator Pressure Setting: 10" w.c.
Gas Inlet Pressure: Max. 13" w.c.
Min. 11" w.c.
IGNITION CONTROLS
Piezo ignitor allows ignition of the pilot without the use of matches or batteries.
Milli-Volt and T-Stat control has four (4) positions:
OFF - All gas to the gas logs is shut off at the valve.
IGN - Valve position to light/maintain a standing pilot.
ON - Valve position to turn ON/OFF log set with remote switch/thermostat.
LOW/HI - Variable position to control flame height (heat output). Both front and rear burners are in operation
to provide realistic glow and yellow flame.
PILOT
The gas log heater is fitted with a specially designed safety pilot light (ODS assembly) which senses the amount of oxygen
available in the room and shuts the gas log heater off if the oxygen level begins to drop below a satisfactory level. The
pilot can only be relit when adequate fresh air is available.
THERMAL GENERATOR
The milli-volt gas log pilot is fitted with a milli-volt generator to provide power for remote activation.
Gas Rate
Model Number Control Max BTU/HR Min BTU/HR
DIS33NTG Millivolt 28,000 19,000
DIS33NVG T-Stat 28,000 19,000
Gas Rate
Model Number Control Max BTU/HR Min BTU/HR
DIS33PTG Millivolt 28,000 23,000
DIS33PVG T-Stat 28,000 23,000

23D8020 7
GETTING STARTED
MAKE SURE YOU HAVE RECEIVED ALL PARTS
Check your packing list to verify that all listed parts have been received. You should have the following:
• Installation/Operating instructions • Black Louvers (5)
• 33" unvented gas heater with brick panels. • Canopy
• Volcanic rock and rock wool • Two (2) anchoring screws
• Mounting screws for canopy
• Log box (refer to installation instructions)
Accessory face plates available to finish the insert.
• DIFACESM Black small face 33"H x 43"W • DIFACELG Black large face 36"H x 50"W
Accessories include brass trim and mounting hardware
The milli-volt controlled version of this heater is the only style designed to be operated with optional devices for ON/OFF
functions. The following options may be used with the milli-volt controlled heater. These options are not packaged with the
log set.
• Hand held Remote with Receiver • Wall switch with 15' wire. • Wall T-stat with 15' wire.
• Hand held Thermostat Remote with Receiver • Thermostat Sensor
• Handle the gas log burner assembly by the grate only. Do not pick the unit up
by the burners.
• Gloves are recommended when handling ceramic fiber logs to prevent skin irritation
from loose fibers. Logs are fragile — handle with care.
WARNING
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 parts
in good condition.
WHAT YOU WILL NEED FOR INSTALLATION
You must have the following items available before proceeding with installation…
• External regulator (for propane / L.P.G. and 1/2 lb. Natural Gas Systems only)
• Piping which complies with local codes • Sediment trap
• Tee joint • Pipe wrench or appropriate size crescent wrench set
• Phillips head screwdriver • Drill with 5/32" bit
• Optional face plate kit. • Manual shutoff valve
• Optional trim kit for installation into wall or free standing Mantle without three piece faceplate
• Pipe sealant approved for use with propane / LP.G (Resistant to sulfur compounds)

8 23D8020
REMOVING SCREEN
Remove fireplace screen by pushing screen frame panel up
and out. See Figure 2.
Figure 2 - Removing Fireplace Screen
GENERAL INSTALLATION INFORMATION
INSTALLING CANOPY
1. Remove the fireplace screen as described in the previous section.
2. Align canopy with the holes in the top frame assembly. See Figure 3.
3. Install the five (5) screws (in owner’s manual packaging) which attach the canopy to the top frame assembly. See
Figure 3.
4. Tighten all screws. Make sure the canopy is level and secure. Install the fireplace screen.
Figure 3 - Installing Canopy
Do not operate the unit without
the screen frame panel and canopy
installed.
WARNING
NOTE: Fireplace screen must
be removed to access log box
and to install canopy.

23D8020 9
GENERAL INSTALLATION INFORMATION
CODES
Adhere to all local codes or, in their absence, the latest edition of THE NATIONAL FUEL GAS CODE ANSI Z223.1 or
NFPA54 which can be obtained from…
American National Standards Institute, Inc.
1430 Broadway
New York, NY 10018
or
National Fire Protection Association, Inc.
Batterymarch Park
Quincy, MA 02269
ADEQUATE COMBUSTION AND VENTILATION AIR
This heater shall not be installed in a confined space or unusually tight construction unless provisions are provided for
adequate combustion and ventilation air.
The National Fuel Gas Code, (ANSI Z223.1/NFPA54), defines a confined space as a space whose volume is less than 50
cubic feet per 1,000 BTU per hour (4.8 m3per kw) of the aggregate input rating of all appliances installed in that space and
an unconfined space as a space whose volume is not less than 50 cubic feet per 1,000 BTU per hour (4.8 m3per kw) of the
aggregate input rating of all appliances installed in that space. Rooms communicating directly with the space in which the
appliances are installed, through openings not furnished with doors, are considered a part of the unconfined space.
UNUSUALLY TIGHT CONSTRUCTION IS DEFINED AS CONSTRUCTION WHERE…
a) walls and ceilings exposed to the outside atmosphere have a continuous water vapor retarder with a rating of 1 perm
(6 x 1011 kg per pa-sec-m2) or less with openings gasketed or sealed; and
b) weather striping has been added on openable windows and doors, and
c) caulking or sealants are applied to areas such as joints around window and door frames, between sole plates and floors,
between wall-ceiling joints, between wall panels, at penetrations for plumbing, electrical, and gas lines, and at other
openings.
Do not install the heater …
• Where curtains, furniture, clothing, or other flammable objects are less than 42"
from the front of the heater.
• In high traffic areas.
• In windy or drafty areas.
WARNING

10 23D8020
W
H
BTU/Hr =
BTU/Hr =
BTU/Hr =
WARNING
The following formula can be used to determine the maximum heater rating per the definition of unconfined space:
(L1+ L2) Ft x (W) Ft x (H) Ft
50
Consider two connecting rooms with an open area between, with the following dimensions:
L1= 151/2Ft., L2= 12 Ft., W = 12 Ft., H = 8 Ft.
(151/2 + 12) x (12) x (8)
50
If there were a door between the two rooms the calculation would be based only on the room with the heater.
(151/2) x (12) x (8)
50
GENERAL INSTALLATION INFORMATION
Figure 4 - Example of a Large Room with 1/2 Wall Divider
Counter
Fireplace
x 1000
x 1000 = 52800 BTU/Hr
x 1000 = 29760 BTU/Hr
If the area in which the heater may be operated is smaller than that defined as an
unconfined space or if the building is of unusually tight construction, provide adequate
combustion and ventilation air by one of the methods described in the National Fuel
Gas Code, ANSI Z223.1/NFPA54, Section 5.3 or applicable local codes.
WARNING

23D8020 11
33"
15
1
/
4
"
22
3
/
4
"
23
7
/
8
"
B
A
9"
Minimum
9"
Minimum
42"
Minimum
CLEARANCES AND HEIGHT REQUIREMENTS
NOTE: Clearances are necessary to combustible
surfaces only. No clearance is necessary for
noncombustible surface.
Sidewall clearances: The clearance from the inside of
the appliance to any combustible adjacent wall should no
be less than 9." See Figure 5.
Ceiling clearance: The ceiling must be at least 42" from
the top of the firebox opening. See Figure 5.
Back wall clearance: The appliance can be placed against
the combustible back wall.
Floor clearance: The fireplace may not be installed onto
any combustible flooring material, such as carpeting, vinyl or
tile without the hearth or a minimum 22 GA (0.030") metal
or a minimum 1/2" wooden base covering the entire width
and depth of the base.
Mantel clearances: The canopy supplied with the unit
must be installed. If a combustible mantel is installed. It must
meet the clearance requirements shown in Figure 8.
The dimensions shown in Figures 5 and 8 and defined in the fireplace manufacturer's
instructions are minimum clearances to maintain when installing this heater. Left and
right clearances are determined when facing the front of the heater.
Follow these instructions carefully to ensure safe installation. Failure to follow
instructions exactly can create a fire hazard.
WARNING
Figure 5 - Sidewall and Ceiling Minimum
Clearances
Figure 6 - Dimensions for Installing in
Masonry Fireplace or a UL Listed Box
BEFORE INSTALLING THE FIREPLACE INSERT
Have fireplace floor and chimney professionally cleaned to
remove ashes, soot, creosote or other obstructions. Close and
seal any fresh air vents or ash clean-out doors located on
floor or wall
Accessory Face Plates
A B
Small 33" 43"
Large 36" 50"

12 23D8020
10"
12"
14"
26"
8"
12"
10"
8"
6"
21/2"
Hood
No combustible materials
within 8”of opening.
Do not cover louvers.
No combustible materials
within 8" of opening.
Do not cover louvers.
Hood
8"
4"
21/2"
6"
8"
HEAT RESISTANT MATERIAL (MINIMUM REQUIRE-
MENTS) WITH NO WOODEN MANTEL OR OTHER COM-
BUSTIBLE PROJECTION
Heat resistant material (minimum requirements) with wooden mantel
or other combustible projection:
To install the heater with a wooden mantel shelf or other combustible
projection above, first measure the heat resistant material shown in
Figure 7.
CLEARANCES and HEIGHT REQUIREMENTS
Example: A mantel
may project from the
wall a maximum of
21/2" at minimum of 8"
above the opening, and
a maximum of 12" at a
minimum of 26" above
the opening.
Figure 7 - Measuring Heat Resistant
Material for Mantel
Figure 8 - Minimum Mantel Clearance
Figure 9 is an example of an unsafe mantel installation. The
mantel projects 4" at 8" above the opening, exceeding the maxi-
mum acceptable distance of 21/2". The mantel also projects 8"
at 10" above the opening, exceeding the maximum acceptable
distance of 6".
If your mantel profile is unsafe, you may either:
• Raise the mantel to an acceptable height or,
• Remove the mantel.
Figure 9 - Unsafe Mantel Clearance

23D8020 13
Combustible
Material
Non-combustible
Material
5"
1”
CLEARANCES and HEIGHT REQUIREMENTS
The gas log heater must be installed at least 5" above any combustible flooring material, such as carpeting or tile, which is
closer than 14" to the base of the fireplace. See Figure 10.
Figure 10 - Minimum Clearance above Combustible Flooring

14 23D8020
225/8"
331/2"
16"
331/2"
16"
331/2"
271/2"
225/8"
317/8"
REF
16"
371/4"
453/4"
153/8"331/2"
641/4"
FIREPLACE FRAMING
If unit is to be “built in,” fireplace framing can be built
before or after the appliance is set in place. BE SURE
THAT ALL PACKING MATERIAL HAS BEEN
REMOVED FROM THE UNDERSIDE OF THE
UNIT PRIOR TO SETTING THE FIREBOX IN
PLACE. Construct fireplace framing following Figures
11 through 14. See Figure 6 on page 11 for fireplace
dimensions. The framing headers may not rest directly
on top of the firebox.
The fireplace may be installed directly on a combustible
floor or a raised platform of an appropriate height. Do
not place fireplace on carpeting, vinyl, tile or other soft
floor coverings. It may, however, be placed on flat wood,
plywood, particle board or other hard surfaces. Be sure
fireplace rests on a solid continuous floor or platform
with appropriate framing for support and so that no cold
air can enter from under the firebox.
Figure 12 - Inner Wall Installation
Figure 14 - Corner Installation
Figure 13 - Stud Location
Figure 11 - Outer Wall Installation
Header

23D8020 15
NOTE: Clearance requirements as detailed
in “Clearances and Height Requirements”
section of this manual must be met before
securing heater in place.
To prevent movement, the heater must be secured
to the floor or hearth.
1. Lift off louvers and remove the screen.
2. Remove log set.
3. To remove the grate and base assembly, take out
two screws as shown in Figure 15.
4. Lift grate and base assembly out of the fire-
box.
SECURING HEATER TO FLOOR
5. Secure the firebox with two anchoring screws
(3/16" x 11/4" length) supplied with the fireplace
system. See Figure 16 .
Note: If the unit is mounted on carpeting,
tile or combustible material without the
hearth, a metal or wooden base covering
the entire width and depth of the base must
be installed.
Figure 15 - Removing Grate and Base Assembly
Figure 16 - Securing Firebox to Floor or Hearth

16 23D8020
NOTICE: A qualified gas appliance installer must connect the heater to the gas supply. Consult all
local codes.
IMPORTANT: Loosen the pipe adapter on the flex tube before installing to the system piping.
Figure 17 - Gas Connection
To Heater
Valve
Stainless
Flexible Tube
CONNECTING THE GAS
Use new black or steel pipe. Internally tinned copper or copper tubing can be used
per National Fuel Code, section 2.6.3, providing gas meets hydrogen sulfide limits,
and where permitted by local codes. Gas piping system must be sized to provide
minimum inlet pressure (listed on Data Plate) at the
maximum flow rate (BTU/Hr).
Undue pressure loss will occur if the pipe is too small.
A manual shutoff valve must be installed upstream of the appliance. Union tee
and plugged 1/8" NPT pressure tapping point should be installed upstream of the
appliance. See Figure 17.
CAUTION
Manual Shutoff
Valve
Pipe
Pipe Coupling
Always use an external regulator for all propane/L.P.G. heaters and high pressure one to two-pound systems only, to
reduce the supply tank pressure to a maximum of 13" w.c. This is in addition to the internal regulator in the heater valve.
CHECK GAS TYPE: The gas supply must be the same as stated on the heater's rating
plate. If the gas supply is different, DO NOT INSTALL THE HEATER. Contact your
dealer for the correct mode.
WARNING
Locations that Pressure
Tapping Point May Be
Installed
Gas Supply
Inlet

23D8020 17
To reach factory installed flex line, go through access door on right or left side of firebox.
CONNECTING THE GAS
CHECK GAS TYPE: The gas supply must be the same as stated on heater's rating plate.
Located behind the control access door (Figure 1, page 5). If the gas supply is different,
DO NOT INSTALL the heater. Contact your dealer for the correct model. Connecting to
the wrong gas type may result in property damage or personal injury.
CAUTION
Connecting directly to an unregulated
propane/L.P.G. tank can cause an
explosion.
WARNING
Figure 18 - Access Holes
Cord Protector
Manual Gas Shutoff
(Recommended Outlet
Positioned Vertical)
Stainless Flex Line
Access Door
for Gas Line

18 23D8020
CHECKING GAS PRESSURE
Test all gas joints from the gas meter to the heater valve for leaks using a gas analyzer or soap and water solution after com-
pleting connection. DO NOT USE AN OPEN FLAME.
Check the gas pressure with the appliance burning and the control set to HIGH.
Open control access door on either side of unit to find valve and regulator referred to below. See Figure 17, page 16.
MILLIVOLT CONTROL (Figure 19)
The valve regulator controls the burner pressure which
should be checked at the pressure test point.
Turn captured screw counter clockwise two or three
turns and then place tubing to pressure gauge over test
point (Use test point “OUT” closest to control knob).
After taking pressure reading, be sure and turn captured
screw clockwise firmly to re-seal. Do not over torque.
Check for gas leaks. Figure 19 - Pressure Test Point Location
Milli-Volt Control
Test Port “OUT”
Connecting directly to an
unregulated propane/LPG
tank can cause an explosion.
WARNING
The stainless flex line is on the right side facing the fireplace and can
connect to either a 3/8NPT female or 1/2NPT male pipe. To connect from
the opposite side, route the pipe under the rear portion of the unit.

23D8020 19
ELECTRICAL WIRING (MILLI-VOLT)
The milli-volt valve is a self-powered combination gas control
THAT DOES NOT REQUIRE 110 VAC TO OPERATE.
Figure 20 - Wiring Diagram
Optional Wall
Switch or Remote
Receiver
Switch
On/Off
Switch
On/Off
Switch
Wall
Switch
ODS
Pilot
Millivolt
Valve
TH = 3
TP = 1
TP/TH = 2
ODS
Pilot
Spade
Terminal
Label all wires prior to disconnection
when servicing controls. Wiring
errors can cause improper and
dangerous operation. Verify proper
operation after servicing.
WARNING
CONNECTING OPTIONAL WALL SWITCH OR THERMOSTAT
1. Use 18 awg, two-wire cable, 15 feet maximum length.
2. At one end of the cable, connect both wires to the wall switch or thermostat. At the other end, connect one wire to TP/TH
and one wire to TH, or connect the wall switch/thermostat to the two male (0.25") terminals on the left side of the unit.
The color of the wires does not matter.
See Figure 20 and installation instructions
provided with optional wall switch, thermo-
stat or remote control for wiring instructions.
A maximum length of 15 feet of 18awg two
conductor wire is to be used for wall switch
or thermostat installations.
Note thermostats and switches must
be suitable for milli-volt operation.

20 23D8020
ELECTRICAL WIRING (MILLI-VOLT)
A. COMPLETE MILLIVOLT SYSTEM CHECK
(“A” Reading - Thermostat contacts CLOSED - Control Knob “ON” - Main burner should turn ON)
a. If the reading is more than 100 milli-volts and the automatic valve still does not come on, replace the control.
b. If the closed circuit reading (“A” reading) is less than 100 millivolts, determine cause for low reading, proceed to
Section B below.
B. Thermopile Output Reading Check
(“B” Reading - Thermostat contacts OPEN - Main burner OFF)
1. Check gas pressure to the unit. If gas pressure is within minimum and maximum on data plate, then check pilot
voltage, 325 millivolts minimum. If the minimum milli-volt reading is not obtainable, replace pilot.
CONNECT
METER SWITCH OR METER
CHECK TO LEADS TO THERMOSTAT READING
TEST TEST TERMINALS CONTACTS SHOULD BE
A COMPLETE 2 & 3 CLOSED CLOSED
SYSTEM
B THERMOPILE 1 & 2 OPEN OPEN
OUTPUT
CHECKING SYSTEM OPERATION
The milli-volt system and individual com-
ponents may be checked with a milli-volt
meter having a 0-1000 mV range. Conduct
each check shown in chart below by con-
nection meter test leads to terminals as
indicated.
CONNECTING REMOTE RECEIVER (Figure 21)
THESE INSTRUCTIONS SUPERCEDE THE SECTION
ENTITLED “HEARTH MOUNT” IN THE MILLI-VOLT
HAND-HELD REMOTE INSTRUCTIONS SUPPLIED
WITH THE REMOTE.
1. Remove cover on control panel to show opening for remote
receiver.
2. Connect the remote connectors located in the unit.
3. Slide remote receiver in the opening of control panel. Use
two screws provided to attach remote receiver to the control
panel.
4. Replace Cover.
NOTE: Do not place remote in combustion chamber.
Figure 21 - Installing Remote Receiver
Remote
Receiver
Cover