Wood & Coal Burning Furnace
Owners Manual
Models: 24A, 30A
TESTED TO UL 391
All installations must be made in accordance with local and state codes
which may differ from this manual.
UNITED STATES STOVE COMPANY
227 Industrial Park Road
P.O. Box 151
South Pittsburg, TN 37380
USSC
851731
WELCOME
...to the world of solid fuel heating! Your new furnace has been designed
and built with a high grade of materials and the strictest regard to quality.
Before you start installing your new furnace, take the time to read these instal-
lation and operating instructions. We have prepared them for your benefit to
save time and provide some helpful knowledge on wood and coal burning.
Save the instructions for future use. It won't take long for you to realize the
benefit of solid fuel heating, however, maintenance is the key to a long last-
ing relationship with your new furnace. These instructions can help you now
as well as in the future.
Note: This owners manual is provided for Forced Air add on furnaces. United
States Stove Company is constantly developing and improving its product
line, therefore, we reserve the right to change specifications without notice.
TABLE OF CONTENTS
General Rules ............................................................................................................................................................4
How It Works ..............................................................................................................................................................5
Installation Instructions...........................................................................................................................................6-9
Assembly .............................................................................................................................................................10-14
Control Box and Electrical Components .............................................................................................................15
Operation ........................................................................................................................................................... 15-19
Accessories ..............................................................................................................................................................19
Trouble Shooting .....................................................................................................................................................20
Parts List & Diagram ........................................................................................................................................... 21-22
Wiring Schematic ....................................................................................................................................................23
How To Order Repair Parts .....................................................................................................................................24
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GENERAL RULES
Rules for the Safe Installation and Operation of Your The furnace is designed to burn air dried wood and
Furnace...
coal at a predetermined firing rate. Over firing could
result in damage to the heat exchanger and cause
dangerous operation. Over firing occurs when the
ash door is left open during operation or a highly
volatile fuel, such as large amounts of small kindling,
is used. Note: This action voids all warranty.
Check local codes, the installation must comply with
strict conformance in regard to clearances.
The Furnace must be installed on a noncombustible
floor.
Follow a regular service and maintenance schedule
of the furnace and chimney for efficient and safe op-
eration.
Connect the furnace to tile lined inside masonry chim-
ney or approved insulated all fuel prefabricated chim-
ney only.
Do not leave the ash door open when the fire is burn-
ing.
Keep smoke pipe connection as short as possible,
using a minimum 24 gauge pipe with a minimum 1/2"
per foot rise from the flue collar to the chimney open-
ing.
Do not let ashes build up closer than 2" to the grate.
With new steel, there is a small amount of oil or dirt
on the metal. You may smell an odor. This is normal
during the first operation. You should assemble the
furnace out of doors and build a small fire in it to
"burn off" this dirt and oil before installing the unit.
Be sure there is a sufficient supply of combustion air
to the area where the furnace is to be located.
Do not over draft the furnace! It is designed to oper-
ate at .04 to .06 inches of water column and must be
set with a draft gauge to maintain a steady draft.
During the first few fires, heat may slightly warp the
front and back panels. This is normal and will not
hamper your unit's operation.
Do not use flammable liquids for starting a fire.
Do not store fuel or combustibles near the furnace.
Some areas of the furnace are hot and could cause
an explosion and possible bodily or property dam-
age.
DO NOT CONNECT THIS UNIT TO A CHIMNEY FLUE
SERVING ANOTHER APPLIANCE.
BURN WOOD OR COAL ONLY THESE MODELS. DO NOT
MIX OTHER THAN THE USE OF WOOD TO START A COAL
FIRE.
Store all ashes in a metal container with a tight seal-
ing lid and allow ashes to cool before disposing of
them, possibly a week.
DANGER - Risk of Fire or Explosion: Do not burn gar-
bage, gasoline, drain oil or other flammable liquids.
Familiarize yourself with the furnace's solid fuel burn-
ing characteristics before leaving unit unattended for
long periods of time.
WARNING - Risk of Fire:
Do not operate with flue draft exceeding 6 inches wa-
ter column.
The loading door and ash door must be tightly closed
during furnace operation to insure safety and effi-
ciency.
Do not operate with fuel loading or ash removal doors
open.
CAUTION -
Do not store fuel or other combustible material within
marked installation clearances.
The furnace has hot surfaces. Keep Children Away.
Do not touch during operation.
Inspect and clean flues and chimney regularly.
In case of a power failure, remove the filter from the
cold air return box if equipped. Do not expect to
keep your home at normal temperatures. Do not
load fuel above the botom of the feed door.
In the event of a chimney fire call the fire depart-
ment, then be sure the furnace doors are closed
tightly and the power to the unit is turned off.
This Furnace Must Be Installed By A Qualified Installer.
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HOW...
How Your New Furnace Works
Unlike conventional heating (gas, oil, electric), wood
or coal heating requires more user attention. Your
furnace, with its automatic combustion air blower,
alleviates the constant need for adjusting the burn-
ing rate common to other units on the market. The
fire, however, must be started and subsequent fuel
added by the user.
WARNING
Note: Improper firing. Wood or coal over firing
occurs when the ash door is left open during
operation or a highly volatile fuel is used.
Coal that exceeds the fire brick line will cause
overfiring...this type of operation will immedi-
ately void any warranty.
Conventional heating system produce heat only
when the thermostat calls for heat. This way of heat-
ing is inefficient and often leaves part of the home
either too hot or too cold. Your furnace is designed
to deliver heat as long as there is a fire in it. The fire
intensity is regulated by the room thermostat, high or
low, the fire continues to produce heat. This heat is
continuously distributed throughout the home by a
distribution blower. This constant supply of heat is
uniform and prevents drafts.
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INSTALLATION
Furnace location
Before you start!
Chimney location is also critical. The furnace must
be placed as close as possible to the chimney. You
want the chimney connector (smoke pipe) to have
a minimum of elbows, two (2) or less. Also, the chim-
ney connector should not have to run more than six
(6) feet to the chimney.
It is very important you check with your dealer, local
fire department, or building inspector. They will be
able to inform you of any state or local codes per-
taining to the location and installation of your fur-
nace.
The ideal location for your furnace is centrally located
in the basement. This allows for an even heat distri-
bution by having all the duct work approximately the
same length. Ideal locations cannot always be used
for one reason or another, therefore, let's look at some
alternatives.
If your home does not have a basement, but a utility
room or garage, make sure there is enough space to
maintain the required clearances stated on the label
located on the furnace. Also, read about combus-
tion air.
CAUTION: The warm-air supply outlet of the Furnace
should not be connected to the cold-air return inlet
of the central furnace because a possibility exists of
components of the central furnace overheating and
causing the central furnace to operate other than as
intended.
After installation, be sure the measured external static
pressure of the central and Furnace is not greater than
those marked on the nameplates.
INSTALLATION #1
INSTALLATION #2
With this installation, a back draft damper (optional) Extending the hot air duct from the furnace into the
is inserted into the heat run before the plenum of the existing plenum will help direct the flow of air from
existing furnace to prevent air from the existing fur- the furnace as well as the flow in the existing furnace.
nace to blow back into the furnace when it is not in Ducting entering the existing plenum at an angle (ap-
use. When a back damper is employed, it should be proximately 45 degrees) will facilitate air flow from
located as close to the existing furnace plenum as the furnace while diverting air from the existing fur-
practical.
nace.
INSTALLATION #3
The baffle on this system should be made the full width
of the furnace plenum in order to properly direct the
air into the distribution ducts.
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INSTALLATION
Your furnace is designed to be added on to existing
Clearance to Combustibles
duct work and operate either with or without another
heat source such as a gas furnace. The following
diagrams illustrate acceptable ways of ducting your
furnace.
Furnace to back wall
Furnace to side wall
Pipe to back wall
Pipe to side wall
30"
12"
18"
Clearance to Combustible Materials
Your Furnace has been tested to determine the SAFE
clearances to combustible material. The clearances
are printed on the label located on the back of the
furnace. The chart on this page also states these mini-
mum clearances. Make sure you follow these when
choosing your furnace location.
18"
Furnace to ceiling
Ductwork to ceiling
30"
18-6-1"
Any hot air plenum connection to a furnace must be
constructed of metal.
NOTE: INSTALL ONLY ON A NON-COMBUSTIBLE FLOOR.
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FLUE RECOMMENDATIONS
CAUTION!
Only a "Class A", all-fuel chimney in-
tended for use with solid fuel should be
used.
"Class A" chimneys are those made from
tile-lined masonry (brick or block) or an
independent laboratory approved all-
fuel factory-built chimney.
WHAT SIZE CHIMNEY SHOULD BE
USED?
The Chimney size to use is either six (6)
or (8) inch round or an 8 x 8" square. If
you use a rectangular chimney, the mini-
mum area it may be is 39 square inches.
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FLUE RECOMMENDATIONS
CHIMNEY INSTALLATION
FACTORY-BUILT OR METAL CHIMNEYS
If your home has an existing metal chimney, the same rules
apply as with masonry chimneys. One thing to be espe-
cially aware of is that "Class B" chimneys are for gas appli-
ances only, not solid fuel burners. If purchasing a new pack-
age, consult with the dealer. He will provide the necessary
parts and instructions for installation.
With the chimney being the most important part to
your installation, great care should be given to its
design.
MASONRY CHIMNEYS
If your intention is to use an existing masonry chim-
ney, check first with your local building official to see
if this is acceptable.
INSTALLING A NEW CHIMNEY
When installing a new chimney, whether it be masonry or
metal, if possible, it is recommended that it is placed within
the house structure. These chimneys remain warmer and,
in turn, radiate this warmth into the house. A chimney lo-
cated outside the house is exposed to cold temperatures
which encourages creosote build-up and poor chimney
draft.
An older chimney, in need of repair, is the GREATEST
fire hazard in any installation.
STOVE PIPE (FLUE PIPE) CONNECTION
The flue pipe you should use is 6" or 8" 24 gauge or
heavier steel pipe.
CONNECTING STOVE PIPE TO A METAL
CHIMNEY
When using a metal chimney, part of the installation
package should include a stove pipe connector. Follow
the instructions provided with the chimney and its parts.
When installing the flue pipe, make sure all joints are
secured with at least three (3) sheet metal screws. This
includes the connection to the flue collar of the fur-
nace. For added protection, use some high tempera-
ture furnace cement to seal each joint.
The stove pipe should slope upward to the chimney
at a rate of 1/2 inch per foot. Any horizontal runs of
stove pipe should not exceed six (6) feet and it should
be supported every four (4) feet. Note: Flue pipe
should be attached inside the flue pipe collar to pre-
vent creosote from running down onto electrical
motors.
CHIMNEY
(OPTIONAL) BAROMETRIC DAMPER
These devices are used to help maintain adequate chimney
draft automatically. They should be installed according to
their instructions and set at .04 to .06 inches of water column.
DRAFT
REGULATORS
MANUAL DAMPER
CONNECTION OF FLUE PIPE TO A
MASONRY CHIMNEY
(RECOMMENDED FOR ADDED SAFETY)
These are used to control chimney draft manually and
should be installed in a convenient place between furnace
and chimney. In the event of a chimney fire, it should be
closed reducing air to the chimney fire.
When connecting flue pipe to a masonry chimney,
there are two ways to go:
1. The flue pipe itself can be cemented into the chim-
ney or;
A combination of both barometric damper and manual
damper may be used. If this is the case, install the manual
damper between the barometric damper and the
chimney.
2. A thimble can be used which is cemented into the
chimney, and the flue pipe fits into the thimble.
VENTILATION FOR YOUR FURNACE
There are many appliances which require "make up" air to
operate. However, with a combustion air draft fan, "make-
up" air is not usually necessary with your wood furnace.
In each case, care must be taken. The outer ma-
sonry (brick or block) must be chipped away, and
the inner liner must be pierced. The flue pipe or
thimble is then inserted flush to the inside face of the
tile liner. NOT ANY FURTHER!
If your home is sealed exceptionally well, use a 3" or 4"
diameter duct vented to the outside and terminating in the
vicinity of the combustion air draft fan. Also, it is possible for
your fans to draw in furnace smoke if there is only dead air
in the area. Note: It's highly recommended that a cold air
return system be utilized. Simply attach a 14" round to a
filter box adapter and attach to cold air return. Also, a
cold air return increases motor life.
Use furnace cement or mortar to seal this connec-
tion. When connecting the flue pipe, make sure the
attachment is secure enough so down draft or "puffs"
do not dislodge it.
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ASSEMBLY ILLUSTRATIONS
NOTE: Your furnace may come partially pre-assembled, but in the case that it is not, follow the instructions
below. Also use these instructions for future maintenance and disassembly. Drawings and photos are for
illustration purposes only. Actual parts may differ.
Prior to assembling, place the unit in the general vicinity of the installation. This should help minimize
handling damage to the unit after assembly.
Attaching the distribution fans. Using four(4) of the
supplied 1/4-20 self-tapping bolts, first install the
blower motor on the right looking at the rear of
the furnace. Then proceed to mount the left blower.
Be sure to place the supplied gaskets between the
motors and firebox back as shown.
2.
1. Unit side shrouds can be assemble by slipping the
side shrouds into place from the top down. If they
don't slide easily, open up the lip of the sides with
a large screw driver then add a little oil. Some-
times a slight tapping with a block of wood and
hammer may be required, but do not force. When
properly installed, the electrical knock-outs will be
at the top left side. NOTE: Should you wish to in-
stall a domestic hot water coil, it should be secured
to the right side prior to assembly. Also, the rear
cast iron baffle must be fastened prior to shroud
installation.
3. Attach the draft fan to the back of the weld on
the throat (2" throat hole with 3 mounting holes).
It's best to use the self tapping screws without the
draft fan to establish threads then mount blower.
The electrical box on the blower should be fac-
ing downward. Draft fan air intake cover should
be set at a 20% opening, about 1/2" opening.
NOTE: The furnace is partially prewired all that is
required is the wiring of the distribution fan (see
wiring diagram, page 18) and the wiring to wall
the thermostat.
4. After mounting the three (3) fans proceed to the
fan control center.
NOTE: The best maintenance for fan motors is to
keep them clean (exceptionally clean). Oiling
with 20W N. detergent once a season will also
help, but cleanliness is what prolongs motors life.
The distribution motors have sealed ball bearing
motors and should not need oiling. However, if
an oil tube is present, you should oil the motors
once a season as mentioned.
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ASSEMBLY ILLUSTRATIONS
5a. Attaching furnace control center box. To sepa-
7. Wall thermostat should be mounted on an up-
stairs inside wall (no outside facing wall) prefer-
ably near your existing thermostat. For more spe-
cific information, read the Honeywell instruction
sheet provided with thermostat. Caution: discon-
nect the power supply before installing. NOTE:
Your wall thermostat and transfer relay are mated
Honeywell products for trouble free installation.
rate outer cover, remove two (2) side screws and
pull off black rheostat knob. Attach box to left
side (facing feed door) with four (4) self-thread-
ing screws. One screw in each corner. (NOTE:
Furnace control center is designed for left side
attachment. Should space prohibit such, revers-
ing shrouds for right side installation is possible,
however, control wires from box will have to be
5b. extended.)
Next, attach the 4x4 junction box below the con-
trol center box, using (2) self-threading screws pro-
vided in the parts bag. (Two starter holes are
provided.)
6. Attach low voltage thermostat No. 18 up to 30 ft.
run No. 16 to 15ft. Run (purchase locally) to ter-
minal plate, screws identified with letters G & R.
(Generally top row center, bottom row right).
Snake wire through holes in top of box. Replace
outer covers & control knob. Under no circum-
stances should you attempt to plug in main power
cord until all wiring and covers are in place.
NOTE: A ground power cord plug is provided;
however, local codes may require fuse box
8. Install top shroud (if removed) by simply placing
shroud on to the top of unit, push down, check
each corner for snug fit.
mounting.
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ASSEMBLY ILLUSTRATIONS
CAUTION: Any hot air plenum connection to a fur-
nace must be constructed of metal.
11. Installing Grates: Install grates together, slip shaker
lug into hole and place grates into frame. Grate
arch faces upward. Check out grate rotation by
placing shaker handle on grate lug (3/4"). Grates
should rotate freely.
9. Installing collar to top: To install hot air attaching
collar, simply bend all tabs right angle under
shroud. This may be possible with thumbs, if not,
remove top and use small hammer.
NOTE: Grates are designed to withstand high tem-
peratures, however, should you overfire the fur-
nace you may fuse or melt grates. This happens
if furnace receives too much air caused by leav-
ing the ash and feed doors open, draft fan cover
wide open, and hot coals or ashes are excessive
in ash pan.
10. Install grate frame (if not already installed): Lay 12. Installing Firebrick: Place 5 bricks on each side
the first grate frame on the side supports and slide
to the back of the unit. Then install the second
grate frame to the front as shown in the picture
above. The smooth ends of the frames should be
together in the middle. For the model 30A, insert
the half grate frame in the middle of the front and
rear frames.
(10 brick total). The bricks tuck under firebox seem.
For the 30A model, use six(6) full brick and 1 half
brick per side. (12 full and 2 half brick total)
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ASSEMBLY ILLUSTRATIONS
13. Installing front and rear cast baffles, heat plates. 15. Installing smoke damper rod to sliding smoke
NOTE: Grate frames and brick will slide forward
and backward to allow baffle to fit. Install front
cast baffle using two (2) 5/16 bolts, nuts & wash-
ers (7/16 wrench will be needed). Place the side
of the baffle that has the two ribs against the front
weld of the firebox. Do not tighten bolts yet.
Place the rear cast baffle to the back of the fire-
box but do not attach the bolts at this time.
damper. First, insert rod through hole above feed
door and push forward.
14. Now slip the rear heat plate in behind the rear 16. Next working through the flue hole behind fur-
baffle. Attach heat plate to the firebox by using
two (2) 5/16 bolts, nuts & washers. First, line up
the top holes and tighten bolts. Secondly, line
up the holes in the rear baffle and the heat plate
with the firebox and attach by using two (2) 5/16
bolts, nuts & washers. Tighten all four (4) bolts.
NOTE: to reach rear bolts you may find it easier to
put your arm through the flue outlet rather than
to reach through the feed door.
nace, line up rod between the two posts on the
sliding smoke damper. Then line up the three (3)
holes for cotter pin insertion, this procedure will
test your patience. It's helpful to have a flashlight
and another person positioning the rod.
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ASSEMBLY ILLUSTRATIONS
17. To install Feed Door handle, insert handle into the 19. To install the dampers on the doors, screw the
door then attach with the 1/2-13 nut and washer
provided. Tighten nut against the backside of
the door then back it off approx. 1/4 turn or until
handle moves freely. (Follow these instructions
for ash door handle installation.)
damper up onto the 1/2-13 carriage bolt pro-
vided. Then screw the damper and bolt into the
door until the bolt protrudes the rear of the door
so that a nut can be attached. Tighten the nut.
18. Find the Feed Door Latch shown in the parts box.
Install with the 1/4-20 bolts and nuts provided.
Adjust the latch so that the door seals properly.
(The ash door latch shall be assembled in the same
manner using the ash door latch.)
18. Installing steel smoke shield. Two (2) holes are
provided above each corner of the feed door.
Slide the two (2) bolts, supplied in the parts bag,
into the holes. Next, place the two (2) clips pro-
vided onto each bolt and then attach the two
(2) nuts on each bolt. Before tightening the bolts
and nuts securely, slide the smoke shield up un-
der the clips, lining them with the slots in the smoke
shield. Tighten the (2) bolts and nuts. (NOTE: The
smoke shield should be able to swing back and
forth.) The smoke shield will help prevent smoke
back puffing if you have a lazy flue.
Page 14
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CONTROL BOX & ELECTRICAL COMPONENT
ELECTRICAL COMPONENTS
140 degree
adjustable disc.
(Left Dist. Blower)
Wall Thermostat
170 degree
limit disc
*(2) 140 degree Adjustable Thermo Disk
*(1)170 degree Thermo Limit Disk
*(1)Relay Transformer
(2) Air Distribution Fan
(1)Draft, Fan
140 degree
adjustable disc.
(Right Dist. Blower)
* Control Box Components
Your new furnace is now completely assembled and
ready to be installed. Make sure you followed the
sections on installation in the front of this manual.
10 BASIC FUNCTIONS OF ELECTRICAL SYSTEM
-- Relay...electrical switching device,
-- Rheostat...current (voltage) reducer increases or
decreases draft fan R.P.M.
-- Distribution Capacitor: Reduces amps required
to activate distribution fan.
-- Transformer: Reduces voltage 110 volts to 24 volts
for thermostat usage. Generally hums a bit.
-- 170 degree limit disk...breaks off electrical current
to the draft fan at 170 degrees
OPERATION OF YOUR NEW SOILD
FUEL BURNING FURNACE.
Check that your draft blower is in working order be-
fore lighting a fire (cover setting 20% open).
Do this by turning the room thermostat to a high tem-
perature so that the draft blower turns on, then turn
the thermostat back to proper setting thus turning the
draft air blower off. Should draft blower not func-
tion, check to see if rheostat setting is on.
-- (2) adjustable140 degree limit disc...closes at set
temperature to operate distribution blowers.
Thermodisc’s range is 95-140. (see illustration for
location)
-- Draft fan...small fan that activates fire, increasing
fire temperature.
1. Wall mounted thermostat requests heat...electrical
contact occurs.
NOW PROCEED WITH LIGHTING
A FIRE.
CAUTION:
2. Current is sent through relay, rheostat, 170 degrees
thermo limit disk to activate draft fan.
3. Upon firebox temperature rise due to air from draft
fan, current passes thru the top/right thermodisc
to activate the left distribution fan. The factory
seting is approximately 120 degrees air tempera-
ture, 500 CFM of air at 120 degrees.
4. Should firebox temperature air reach 140 degrees,
current is directed thru the bottom/right
thermodisc to activate the second fan for 1,000
CFM of air.
Never use chemicals or fluids such as gasoline,
charcoal lighter fluid, drain oil or kerosene to
light a fire in your furnace. This would be like
checking the level of gas in your car with a
lighted match.
1. Pull bypass damper out (opens up flue hole).
2. Make sure your flue pipe damper is open. Place
several pieces of crumpled paper in the center of
your firebox. In a crisscross pattern, place a couple
of handfuls of dry kindling wood, then several small
dry pieces of firewood.
Both blowers will continue to run until air tempera-
ture drops approx. 20 degrees below the set point
on the thermodisc.
3. Ignite the paper and close the door. Do not at-
tempt to open the door immediately after ignit-
ing the fire. There could be a flame flash out.
The above is somewhat basic, however, it's offered
so you can understand your furnaces electrical func-
tions and enjoy it more.
4. It will take a few minutes for the fire to establish
itself. Once you have some good red hot burn-
ing coals, add larger pieces of wood. All Chim-
neys and hookups act differently. After a while,
you will find out how your unit works best for start-
ing.
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Page 15
OPERATION
5. Push in bypass damper after fire has progressed.
MAINTENANCE
6. Your furnace is capable of putting out many BTU's,
so don't fully load your furnace until you have be-
come familiar with the operation of the furnace.
Keep chimney and flue pipe clean by cleaning at
least twice during a heating season.
Keep in mind, a full load will not always give you CREOSOTE- FORMATION AND
the best results for your needs. Note: With new
steel, there is a small amount of oil or dirt on the
metal. You may smell an odor. This is normal dur- When wood is burned slowly, it produces tar and
ing the first operation. You may want to assemble other organic vapors which combine with expelled
the furnace out of doors and build a small fire in it moisture to form creosote. The creosote vapors con-
to "burn off" this dirt and oil before installing the dense in the relatively cool chimney flue of a slow
NEED FOR REMOVAL
unit.
burning fire. As a result, creosote residue accumu-
lates on the flue lining. When ignited, this creosote
makes an extremely hot fire.
7. When loading your furnace that has existing hot
coals, pull the bypass damper out and rake the
red hot embers over grate evenly. Put a few smaller The chimney connector and chimney should be in-
pieces of wood on the coals first, then load up to spected at least twice monthly during the heating
the middle of the feed door.
season to determine if a creosote buildup has oc-
curred.
8. Set rheostat setting for type and condition of coal
or wood. Hard coal and wood requires more If creosote has accumulated, it should be removed
forced air than soft, so experiment with dial set- to reduce the risk of a chimney fire.
ting. Start with a center dial setting. The draft fan
CAUTION
cover also requires experimenting with. Start with
a 20% opening.
If you have a chimney fire, we recommend the
following immediate actions:
9. Set the furnace thermostat for comfort. Set the other
thermostat 10 degrees lower.
1. Alert everyone in the house.
10. Use caution when opening loading door. Avoid
opening loading door rapidly. This could cause
flames to flash out the door. This occurs when there
is unburned fuel and a large amount of gases on
the top of the firebox. When the door is opened
oxygen is combined with the gases and ignites.
2. Shut any furnace doors, disconnect power to
the unit, and close any dampers. This should
take no longer than a few seconds.
3. Call the fire department.
Keeping your chimney and stove pipe clean is the
best insurance against chimney fires. Note: Smoke
detectors and fire extinguishers should always be a
part of your equipment.
ASH REMOVAL
Every morning when there is just a bed of hot embers,
shake the grate very, very lightly.
Once every week or two, depending on how much
fuel you burn, ashes should be removed. Note: A 2"
to 3" bed of ashes will prolong wood burning and
protect grates.
If you clean your own chimney and stove pipe, we
recommended purchasing the equipment profession-
als use. Wire brushes are available in enough sizes
and shapes to be a snug fit inside any common flue.
CAUTION
Once a week let your furnace burn with ash door
open for a maximum of fifteen minutes while in at-
tendance. This will help minimize creosote buildup.
Also placing a surface magnetic thermometer on
flue pipe is helpful to keep temperatures at 300 to
400 degrees. Duct temperatures should be 115 to
125 degrees at 12" above furnace.
Never let ashes build up to grate level. This will
reduce the life span of your grate, and void grate
warranty.
To remove ash pan simply open ash door and pull out
your ash pan. But remember, the ash pan can get
very hot. Dump ashes in a metal container with a lid
and place on a non-combustible surface.
CAUTION
Never use anything but a metal container to put
your ashes in. Every year fires are caused by empty-
ing ashes into cardboard boxes or paper bags.
Page 16
USSC
OPERATION
of the ashes without disturbing the fire. Stop when
BURNING COAL
you see a glow in the ashes or the first red coals fall
into the ash pan. Excessive shaking wastes fuel and
can expose the grate(s) to very high temperatures
which can cause warpage or burnout.
Your furnace is capable of burning both Bituminous
and Anthracite coal. Anthracite is perhaps the best
coal fuel because its long even burn time, high heat
output, and cleanliness make it a good choice for
the home. However, keep in mind it is a much more For overnight operation (long duration burn time)
difficult fuel to use, requires more care and patience, shake the fire and add coal, retaining your center
is not so widely available, and is usually much more cone. Once the volatiles are burned off, close the
expensive than bituminous.
feed door and adjust your stove pipe damper. Then
adjust your thermostat to the desired heat level.
SIZE OF COAL: Most sizes of Bituminous Coal will
work in your New Furnace, for best results we recom-
mend large nut coal to small egg coal (1-3/4" dia. to
4" dia.). When burning Anthracite, use egg or bro-
ken with sizes between 2-5/16" thru 4-3/8". Note that it
is important to the long life of your furnace to buy
coal which has been sized and cleaned. Cleaning
insures removal of rocks and other materials. Never
use coal smaller than 1" or larger than 5" in diameter.
Small sized coal will smother the fire. Too large a size
of coal will not burn well.
You will have more MAINTENANCE with bituminous
than with anthracite coal as more soot will collect on
heating surfaces and in pipes, requiring more frequent
cleaning.
ANTHRACITE: Before starting the fire open - the stove
pipe damper, open the ash pit door and feed door,
place newspaper, finely split kindling on the grate,
and light the paper. Add larger hard wood after
kindling is burning brightly. CAUTION: Never use
gasoline, lantern fuel, kerosene, charcoal lighter fluid,
or other flammable liquids to start or freshen up a fire
in this heater. Place the larger pieces of wood on
the fire so that they are slightly separated and form a
level for the addition of coal. It will take 10 to 20
minutes before this wood is thoroughly ignited. Add-
ing coal too soon will cut the air supply and smother
the fire.
STOVE OPERATION: All coal fires should be started
with wood which will allow the fire to get hot enough
to ignite the coal. The best ignition fires utilize dry
pine or other resinous soft woods as kindling, with
hard wood (oak, hickory, ash) added to increase
the heat prior to addition of the coal.
Add a thin layer of coal (preferably smaller chunks)
to the wood fire, being careful not to disturb it too
much or cut off the draft. Then, add a second heavier
layer after the coal is ignited and burning well. If
necessary, add a third layer to bring the coal up to
the top of the front liner (not above!). Be sure you
have closed your ash door.
BURNING BITUMINOUS: Once your kindling and
wood fire has produced a bed of well established
coals, start adding coal in layers allowing each to
ignite before adding more. Bituminous has a high
volatile content and, as a result, should be fired with
the "conical method" - with the highest portion of your
firebed in the center of the firebox. The first flames
will be long and generally orange or yellow and pro-
duce quite a bit of smoke. As the gases burn off the
flames become shorter, change colorand produce
less smoke. Once the fire is WELL ESTABLISHED add
coal to the center of the firebox forming the cone.
Burning in this fashion allows heat to drive off the vola-
tile gases, and turbulence created increases the burn
efficiency. You will have to experiment with your par-
ticular setup as no two chimney's or installations are
going to be the same. Just remember to allow
enough secondary air to enter the firebox and keep
your stove pipe damper open so that volatiles are
properly burned. Before refueling, take the time to
break up the cone a little with a poker, especially if it
has caked over or formed a crust. But, be careful not
to mix the coal as this increases the chances of form-
ing clinkers. When shaking the grate(s) be gentle.
Just a few short movements is better than a lot of
agitation. The objective is to remove a small amount
Before adding further fuel, be sure you leave a red
spot of glowing coals in the center of the firebox to
insure that you have not smothered the fire and to
help ignite thegases given off by the new charge. A
deep charge will give a more even heat and a longer
fire, but it may take one to two hours before the whole
bed is fully ignited.
When the fire is well established and the room is be-
coming warm, partially close the dampers. You will
have to experiment with your particular setting of the
damper and controls as your chimney provides the
draft necessary to not only exhaust the smoke, but to
pull combustion air into the heater as well - and no
two chimney's perform the same. Leave the ash pit
damper at least partially open to prevent the fire from
going out. Adjust the stove pipe damper to reduce
the draft on the fire. With anthracite you will see short
blue flames above the coal, except when the fire is
started or a new charge is added. If, however, there
Page 17
USSC
OPERATION
If, however, there is no flame then the fire needs more The amount of shaking is critical. Too little or too
air from the bottom (unless it is near the end of its much of both can result in the extinguishing of a fire
burn cycle and needs to be recharged).
due to blocked air flow. The proper amount nor-
mally occurs when red coals first start to drop through
onto the bed of ashes.
Only when the coal is burned down to half its origi-
nal depth is it time to add fresh coal. When doing so,
open your stove pipe damper, which will allow the No furnace ever should be "poled" from the top. This
fire to burn off any accumulated gases. Open the can lead to clinker formation and compacting of
feed door, and with a small rake, hoe or hooked the coal and ashes, which results in clogged air pas-
poker pull the glowing coals to the front of the fire- sages.
box. Try not to disturb the fire too much. Next, add a
fresh charge to the back being careful not to seal off
ASHES: Ashes never should be allowed to accumu-
the top. Close the feed door but leave the spin
damper open for a few minutes until the volatile gases
have burned off. It is not necessary to shake down
the ashes each time you refuel your furnace. Experi-
ence will be your best teacher.
late in the ash pit so that they in any way impede the
flow of combustion air to the fire. Excess ash accu-
mulation can cause the fire to go out and also can
cause severe damage to the grates because of the
absence of a cooling flow of air beneath them.
Ashes always should be emptied into a metal con-
tainer. Coals can remain hot many hours after a fire
is out. Coal ashes should not be put on gardens as
they do not contain beneficial minerals like wood
ashes, and may cause ground water pollution.
BANKING THE FIRE: For extended operation, such
as overnight, you will need to bank the fire. To do so
heap coal up along the sides and back of the fire-
box so that the fire gradually burns it over a longer
period of time. You will also reduce the intensity of
the fire without letting it go out. Follow the same pro-
cedure as for refueling. If possible, avoid shaking, as
a heavier layer of ash will help reduce the intensity of
the fire during this time. After loading, let the fire es-
tablish itself for about 30 minutes. Then close your
damper to the point where the house does not be-
come too cold. It is important that you begin bank-
ing early enough before retiring or leaving that you
can make necessary adjustments after the fire is well
established.
Coal produces considerably more ash than wood,
so the intervals between emptying are much shorter.
For equal heat output, coal will produce seven (7) to
ten (10) times more ash than wood.
CLINKERS: Clinkers can occur in any coal furnace
during the process of burning. These are hard pieces
of fused ash that form in the firebox. They can be-
come hard and large in size and, therefore, cannot
be shaken through the grates in a coal stove. When
there is an appreciable accumulation, the fire will go
out because insufficient air is allowed to pass through
the clinkers to the burning coal.
To revive a coal fire that is almost out, you should (1)
open the ash door and stove pipe damper to get a
good draft through the grate. (2) place a thin layer
of dry coal over the entire top of the fire. DO NOT
POKE OR SHAKE THE FIRE AT THIS TIME! (3) after the
fresh coal has become well ignited shake the grate
(just a little) and you will be ready to refuel.
Once large clinkers have formed, they can be re-
moved only from above the grates. This usually means
the fire must be allowed to go out before they can
be removed.
Clinkers formation can occur from a number of dif-
ferent causes or a combination of causes. Some of
these are:
DO NOT burn coke, charcoal, high volatile bitumi-
nous coal, sub bituminous, lignite or cannel coal
(sometimes called channel coal or candle coal).
NEVER burn wax or chemically impregnated sawdust
logs - their intended use is for fireplaces only. NEVER
fill your stove or furnace above the firebrick or cas
iron liner.
• Poor quality coal-excess ash content and/or too
low a heat of fusion.
• Too hot a fire (too much draft).
• Too shallow a bed of coals.
• Too deep a bed of coals.
• Excessive Shaking.
SHAKING: Shaking should be done only when there
is a hot fire.
The frequency of shaking will depend on the degree
of burning. Shaking should be done at least once a
day and preferably twice a day.
• Poking the fire from the top.
• Too little air (draft) after a long, hot fire (caused by
rapid adjustment of draft from a very high setting to
a low setting).
Best results from shaking the rocker grates will occur if
short "choppy" strokes are used rather than long, even
strokes.
Page 18
USSC
SAFETY - OPERATION
Whenever the loading door is opened, it should be cracked slightly (for about ten (10) seconds) to allow
oxygen to enter and burn any combustible gases that are present before fully opening. Failure to do this
could result in sudden ignition of the unburned gases when the door is opened. This furnace is equipped
with a safety latch system to reduce the rsik of sucjh an ignition. Always wear a glove to protect you hand
from the heat.
With the exception of the start-up period, the ash pit door should never be left open. Serious damage to the
stove can occur from overheating. In extreme cases, this overheating could be the cause of an "unfriendly
fire".
Coal furnaces are subject to the same installation clearance standards as wood furnaces. Never burn coal
in any furnace that does not have an airtight, unified chimney system.
Coal furnaces should not be installed in any chimney that has had a history of back-drafting or flow rever-
sal. Also, coal furnaces should not be installed in any chimney having an excessively large flue. These
conditions can cause improper draft, resulting in carbon monoxide entering the house rather than being
drawn up the chimney. Remember, coal gases are toxic.
Sulfur dioxide, sulfur trioxide and other ions released from coal burning may corrode stainless and masonry
chimneys, and even terra cotta chimney liners and brick in nearby buildings. Coal with high sulfur content
will destroy chimneys especially fast if soot sits in the flue for extended lengths of time. It is important to clean
chimneys regularly.
CAUTION
HOT WHILE IN OPERATION. CONTACT MAY CAUSE SKIN BURNS. KEEP
FURNISHINGS AND OTHER COMBUSTIBLE MATERIALS A CONSIDERABLE
DISTANCE AWAY. TO AVOID EXCESSIVE TEMPERATURES, DO NOT OPER-
ATE WITH THE FUEL FEED AND ASH DOORS OPEN. TO PREVENT FLAME
AND SMOKE SPILLAGE, THE SLIDE BAFFLE MUST BE PULLED OUT AND THE
FEED DOOR MUST BE CRACKED FOR 10-15 SECONDS BEFORE DOOR IS
OPENED FULLY.
ACCESSORIES
Domestic Hot Water Coil
Part # 11WCK
USSC
Page 19
TROUBLE SHOOTING
TROUBLE-SHOOTING, PROBLEM SOLVING FOR YOUR FURNACE
1. Problem: Smoke puffs from furnace.
Solution:
Problem: Distribution blower vibrating.
Solution:
A. Tighten Allen Screw on squirrel cage.
B. Check for bad fan bearings.
C. Also oil 3-4 drops of 20w non detergent oil.
4.
A. Check chimney draft. Check for blocked chim-
ney or flue pipe. Use mirror to check chimney
clearance.
B. Check ash pit - if too full, empty.
C. Make sure furnace room is not too airtight.
D. Make sure all chimney mortar connections are
air tight.
Problem: Distribution blower continues to run or
will not run.
Solution:
5.
E. Check clean out door. Make sure it's airtight.
F. Check chimney for possible down-draft caused
by taller surrounding trees or objects. Correct
with proper chimney vent cap.
G. Check the possibility of cold chimney forcing
cool gas blockage. Remedy by properly insu-
lating chimney with noncombustible liner and
non- combustible insulation.
A. Check to see if thermodisc 110 degrees (top
right side) is faulty. Use match or lighter for click
or jumper wire.
B. Check to see that blower is properly wired. (See
Wiring and Assembly Instructions).
Problem: Draft blower continues to run or will not
run.
6.
H. Fuel may be too wet.
Solution:
I. Make sure no other fuel burning devices are
connected to the chimney impairing the draft.
A. Check rheostat switch for on position. Check
wiring.
B. Check thermostat or thermostat wire for short.
Make sure temperature is calling for or not call-
ing for heat. Set thermostat at 80 degrees.
C. Check to see if thermodisc 170 degrees (left side)
is faulty. Use match or lighter for click or jumper
wire.
2. Problem: Inadequate heating being delivered to
your home.
Solution:
A. Check home insulation - is it adequate?
B. Check hookup to furnace - is it installed cor-
rectly? (review manual)
C. Cool air inlet may be inadequate or furnace
room too airtight, 14" inlet for 12" outlet.
D. Your wood fuel may be too low grade. Hard
woods are recommended.
E. Make sure your hot air duct (and other duct
work) is airtight.
If furnace room is warm but your home isn't,
check back draft dampers.
F. Is air inlet to the blower open? Check filters.
G. Fuel may be too wet.
Problem: Odor from first fire.
7.
8.
Solution:
A. The odor remains, call your dealer immediately.
A defective weld can cause a fume leak.
Problem: Excessive creosote.
Solution:
A. Check the grade of wood you are burning.
B. Make sure your unit is serviced by its own proper
chimney.
C. Check length of flue pipe and its connections.
D. Make sure you are burning the smallest, hottest
fire to adequately heat your home.
E. Also see Solutions to Problem 1.
F. Use a magnetic surface thermometer on flue
pipe and operate between 300 and 400 de-
grees.
H. Check draft blower cover, setting 1/2" open-
ing.
I. Rheostat setting is fully open.
3. Problem: Excess smoke or flames coming out door
when refueling.
Solution:
A. Open bypass damper. Wait 15 seconds and
open door slowly - then refuel.
B. Check length of flue pipe to chimney. Your
unit should be within six (6) feet of your chim-
ney.
C. Make sure chimney cap is not too close to the
top of the chimney.
Problem: Poor seal around unit door.
Solution:
A. Bend door latch in to tighten seals.
9.
D. Check chimney draft-make sure chimney flue
pipe is clean and chimney is of adequate
height.
E. Make sure you're not suffocating the fire with
excess amounts of unburned fuel.
Page 20
USSC
REPAIR PARTS DIAGRAM
USSC
Page 21
PARTS LIST
KEY
PART #
DESCRIPTION
QTY.
1
-
2
-
3
-
4
5
6
24490
25613
24489
25614
24488
25615
69542
69559
89636
83835
83444
40379
83503
83274
891423
83045A
23786
83339
83250
23823
891135
24501
83445
23787
69543
69568
40366
24487
24496
40369
40349
40376
40350
24828
25612
83874
89066
891414
24220
C97999
89799
80496
89319
80422
69081
24492
80130
80388
80390
80090
80131
80231
LEFT CABINET SIDE
1
1
1
LEFT CABINET SIDE (30A)
RIGHT CABINET SIDE
RIGHT CABINET SIDE (30A)
CABINET TOP
CABINET TOP (30A)
ASSY., FEED DOOR
ASSY., ASH DOOR
DOOR HANDLE
1/2” WASHER
1/2-13 LOCK NUT
1
1
1
2
2
2
2
2
4
4
1
4
4
1
3
1
2
2
7
8
9
SPIN DAMPER
3/8” CARRIAGE BOLT
3/8-16 LOCK NUT
10
11
12
13
14
15
16
17
18
19
20
21
22
-
23
24
25
26
27
28
29
30
-
N/S
31
N/S
32
33
34
35
36
37
38
39
40
41
42
43
44
45
DOOR PIN
3/8” WASHER (USED FOR DOOR ADJUSTMENT)
DOOR LATCH (FEED DOOR)
1/4-20 BOLT
1/4-20 KEP NUT
LATCH CATCH (ASH DOOR)
SPRING HANDLE (NICKEL)
SMOKE CURTAIN
1/4-20 CARRAIGE BOLT
SMOKE CURTAIN CLIP
ASH PAN ASSEMBLY
ASH PAN ASSEMBLY (30A)
FIREBOX LINER
REAR HEAT PANEL
FRONT HEAT PANEL
SHAKER GRATE FRAME
SHAKER GRATE
HALF GRATE FRAME (30A)
HALF GRATE (30A)
DAMPER ROD
DAMPER ROD (30A)
1/8 DIA. x 1-1/2" COTTER PIN
FIREBRICK (MODEL 30A USES TWO(2) MORE BRICK)
HALF FIREBRICK (30A ONLY)
INSIDE COVER PLATE
GASKET, WATER COIL COVER
STUB COLLAR
1
2
1
1
2
2
1
1
1
1
10 (2)
2
1
1
1
2
2
1
1
1
1
2
1
1
1
1
500 CFM BLOWER
BLOWER GASKET
FORCED DRAFT BLOWER
CONTROL CENTER BASE ASSEMBLY
CONTROL CENTER COVER
TRANSFORMER, FAN CENTER
ADJUSTABLE 140°F THERMODISC
LIMIT DISC, 170°F
RHEOSTAT w/KNOB
4 x 4 JUNCTION BOX
COVER, JUNCTION BOX
Page 22
USSC
WIRING SCHEMATIC
USSC
Page 23
HOW TO ORDER REPAIR PARTS
THIS MANUAL WILL HELP YOU OBTAIN EFFICIENT, DEPENDABLE SERVICE FROM YOUR
FURNACE, AND ENABLE YOU TO ORDER REPAIR PARTS CORRECTLY.
KEEP THIS MANUAL IN A SAFE PLACE FOR FUTURE REFERENCE.
WHEN WRITING, ALWAYS GIVE THE FULL MODEL NUMBER WHICH IS ON THE NAMEPLATE
ATTACHED TO THE HEATER.
WHEN ORDERING REPAIR PARTS, ALWAYS GIVE THE FOLLOWING INFOR-
MATION AS SHOWN IN THIS LIST:
1. THE PART NUMBER
2. THE PART DESCRIPTION
3. THE MODEL NUMBER: 24A
30A
4. THE SERIAL NUMBER: ____________________
UNITED STATES STOVE COMPANY
227 INDUSTRIAL PARK ROAD
PO BOX 151
SOUTH PITTSBURG, TN 37380
(423) 837-2100
Page 24
USSC
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