Keystoker KAA-4 User manual

Schuylkill Haven, PA.
“SAVE THESE INSTRUCTIONS”
HOT WATER BOILERS
Safety, Installation and Operating
Instructions enclosed.
Please read and understand these following instructions. If
instructions are not followed; a fire may result causing
property damage, personal injury, or even death.
Installations must be performed by a qualified installer.
Follow All local building and zoning codes.
SAVE THESE INSTRUCTIONS
Instruction Must be with the owner of the boiler
Keystone Manufacturing Company
60 Keystoker Lane
Schuylkill Haven, PA 17972
[phone]
[e-mail]
© July 2019 Rev 02

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Hot Water Boilers
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About Us
Keystoker had its inception in 1946.
Two electrical engineers saw the need for a way to conveniently burn anthracite coal,
which was plentiful, but heating with coal had a bad reputation of being dirty and requiring
maintenance several times a day. Our engineers developed an automatic stoker unit
equipped with a coal hopper that held enough fuel for several days. This allowed the coal to
be cleanly burned and without frequent maintenance. They then saw the need to make a
hot water boiler specifically designed to burn coal and built them in multiple sizes to meet
our customers' needs.
As prices of energy continued to escalate, Keystoker continued its research. Over 70 years of
research has developed a patented feed-in system, a patented flat grate, and a patented
thermal heat exchange, which has produced the highest efficiency possible.
Keystoker --- Made in America with American Technology and utilizing American resources is
now known internationally for its simplicity, quality, and dependability, all this and still an
economical price.

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Hot Water Boilers
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Table of Contents
Company Introduction
2
SAFETY
4
UL Label
4-5
Precautions & Definitions
6
General Safety Statement
6
Safety
7-9
Hot Water Specification Chart
10
Installation
11
Boiler Placement
11
Set Up Boiler
12
Supply & Return Piping
12
Boiler Fill & Domestic Water Piping
12-13
Installation & Piping of Accessories
13
Jacket/Shroud & Stoker Unit Installation
13
Control Installation & Electrical Wiring
14
Stack/Flue Pipe & Barometric Damper Installation
14
Initial Start Up & Water filling
14
Fuel Type
14
Operation
15
Start Up
15
Check Draft
15
Initial Coal Feed
15
Diagram 1 -Continuous Operation
16
Diagram 2 –Intermittent Operation
17
Figure 2 –Initial Main Combustion Air Setting
18
Component Description & Operation
19
Figure 4 –Stoker Unit components
20
Controls Descriptions
20-21
Figure 5 - Typical Control Arrangement
21
Setting Draft
22
Setting Timer
23
Maintenance
23
Testing Controls & Safety Devices
23
Aqua Stat
23
Low Water Cut Off
23
High Limit w/ Manual Lock Out
23
Safety Relief Valve
23-24
Cleaning & Lubrication of Boiler
24
Ash Pan Emptying
24
Troubleshooting Guide
25
Diagrams
26
Wiring Diagram-Boiler
26
Wiring Diagram-Boiler: Coal Oil Option
27
ISO Plumbing Diagram Single Boiler
28
ISO Plumbing Diagram 2-Boilers
29
Typical Zone Valve Wiring Diagrams
30
Boiler Major Components
31
Parts Ordering
32
Warranty
32
Check list
33
Notes
34

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Tested per UL 2523, first edition
CAN/CSA-B366.1, January 2011
MH60075 SOLID FUEL-FIRED BOILER ASSEMBLY
Keystone Manufacturing Company
60 Keystoker Lane
Schuylkill Haven, PA 17972
Phone [phone]
Models: KAA-4, KFL-6, KA-6, KB-8, KC-10, KD-12, KE-15, KF-18, KG-22
Serial Number
Date manufactured stamped on data plate attached to boiler
BURN ONLY ANTHRACITE COAL
POWER SUPPLY- 120V, 60 Hz, use not less than 14 AWG wire and not less than 15A breaker. Total power usage
by unit 5.5A. Installation to be performed only by a qualified heating professional. Follow manufacturer’s
instruction manual for installation and operation of the unit. Follow manufacturer’s instruction manual for wiring
diagrams and field wire connections. Use copper conductors only. Use only chimney parts as referenced by
manufacturer’s installation manual.
DO NOT CONNECT THIS UNIT TO A CHIMNEY FLUE THAT SERVICES ANOTHER APPLIANCE
Installation Clearance from combustible material:
Fire/Ash Door 30 inches
Plain side 6 inches
Stack End 18 inches
Hopper End 6 inches
Top 12 inches
Floor Non-combustible
(preferably concrete)
H
DO NOT ATTEMPT TO LIGHT A FIRE WHEN THERE IS OIL VAPOR PRESENT.
DO NOT BURN GARBAGE, GASOLINE, NAPTHA, ENGINE OIL, OR OTHER INAPPROPRIATE
MATERIALS.
Hot water boiler shall not exceed 160 psig. (1103 kpa) and a temperature exceeding 250
deg.F.(121deg.C.).
For safety, keep fire and ash pit doors tightly closed.
The heat exchanger, flue pipe and chimney must be cleaned regularly to remove accumulated fly
ash.
Ensure that the heat exchanger, flue pipe and chimney are cleaned at the end of the heating season
to minimize corrosion during the summer months.

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The appliance, flue pipe and chimney must be in good condition.
These instructions also apply to a draft inducer.
Refer to owner’s manual.
Do not alter this equipment in any way.
Minimum allowable draft setting is -.01 inches of water column and the maximum allowable draft
setting is -.04 inches of water column taken over the fire in a predrilled hole in the fire door.
The maximum ampere rating of the circuit is 15A and the minimum ampere is 10A.
The essential parts of the boiler, stoker unit, jacket, controls, exhaust pipe and draft regulator.
Suitable for potable water and space heating.
Use copper conductors only for field wiring.
For power supply connections use 14 AWG or larger wires, acceptable for at least 105 degrees “C”.
For after loss of power operation, turn power to the off position and re-light fire.
WARNING RISK OF FIRE
Danger risk of fire and explosion. Do not burn garbage, gasoline, drain oil, or other flammable liquids.
Do not operate with flue draft exceeding -.04 inches of water column.
Do not use chemicals to start unit firing.
Do not burn garbage, gasoline, fuel oils, or other flammable liquids or materials.
Do not operate while loading fuels or removing ash.
Do not store fuel or other combustible material within marked installation clearances.
Inspect and clean the flues and chimney regularly.
Caution hot surface.
Hot surfaces keep children away.
Do not touch during operation.
Danger-to-avoid injury from moving parts shut off the equipment
before working on unit.
Replaceable fuse 15 AMP.
In the event of a “runaway fire”, move on/off switch to the off
position, turn hot water on using a spicket/faucet and let run until
the boiler cools down.
The potable water heater shall not be connected to any part of the
heating system or appliance that is for non-potable water. Toxic
chemicals such as boiler treatment, oils and dirt may be present and
shall not be introduced into the potable water heater.

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Safety
Precautions & Definitions
Our boilers have been designed for safe and reliable operation when properly used and
maintained in accordance with instructions contained in this manual. A stoker boiler is a
precision system that if not properly installed or maintained can be hazardous, cause burns,
electrical shock or even loss of life. Keystoker shall not be liable for physical injury, damage
to property or death caused by a failure to observe the instructions in this manual.
Please note the following symbols are used to denote special attention within this manual:
Burn & Scalding Hazard. Operating procedure, practice etc. which, if not correctly
followed, could result in burns or scalding from hot water.
Electrical Hazard. Particular care must be taken when electrical power source to the
unit is energized.
Warning. Operating procedure, practice etc. which, if not correctly followed, could
result in personal injury.
Caution. Operating procedure, practice etc. which if not followed could result in
damage or destruction of unit.
Fire. Operating procedure, practice, etc. which if not followed could result in severe
burns, bodily harm, loss of life and property damage.
Death. Critical situation or operation of unit that may causedeath.
General Safety Statements:
Thoroughly read and understand all instructions
Always leave this manual with the owner of the boiler.
A carbon monoxide (CO) detector has been supplied with yourboiler.
o The CO Detector needs to be plugged in.
o CO is colorless, odorless & tasteless gas that can be deadly if not monitored or
detected properly.
Danger risk of fire or explosion. Do not burn garbage, gasoline, drain oil, or other
flammable liquids. Do not use chemicals or fluids to start fire.
Boiler surfaces may be hot while in operation. Keep children away. Do not touch
during operation
Do not connect this unit to a chimney flue serving anotherappliance
Please follow all local building and Zoning ordnances
Use the proper fuel type as noted in this manual

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Safety
Only fill hopper to the maximum fill line, Do not fill with wet coal.
Coal should not overflow top of the hopper.
Do not store fuel within the recommended installation clearance for proper ash removal and
refueling the boiler.
Fuel can be store as followed, large coal bin, buckets or bags.
Solid fuel burning appliances need to be cleaned frequently, soot and ash can accumulate
restricting heated air and exhaust flow through the boiler.
The type of fuel that will be burned is Anthracite coal. Anthracite does not create creosote,
but does Create soot or a fine fly ash that will accumulate in stack pipe.
Furnace and stack must be cleaned at least once a year. Stack may need to be cleaned
more often depending on coal consumption.
Chimney should be as per NFPA 211- 316 Stainless Steel Liner or Brick Lined and in good
condition, height requirement is 16 feet.
*For Canadian installation: as per NFPA 211- Chimney must be 304, 316, 404, 443 stainless
steel.

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Maximum flue draft shall not exceed -.06 inches of water column. Exceeding maximum draft
will result in an out of control burn.
Make sure boiler room is large enough for adequate combustion air. If the room is too small,
an outside air vent must be used.
All control and electrical covers shall be installed before being energized. Do not remove
covers for service or maintenance unless power supply has been shut off. This could be done
with the supply breaker or by removing the fuse. Test with multimeter to ensure no voltage is
present.
Fill hopper using a bucket or shovel, bags can be dumped directly into hopper if bags are not
water logged. Care should be taken when filling hopper, safety glasses and gloves are
recommended when doing so. Do not overfill hopper.
A carbon monoxide detector has been supplied with your boiler. You must plug it in.
THE BURNING OF ALL FOSSIL FUELS GENERATES CARBON MONOXIDE GASES. CARBON MONOXIDE
GASES ARE TOXIC. CAN CAUSE DIZZENESS, FATGUE, NAUSIA AND DEATH.
To prevent toxic carbon monoxide gases from entering the home or building certain precautions must
be taken.
Ash Tubs must be emptied on a regular basis to prevent ashes from overflowing into the
ashpit area of the boiler. Excessive ash accumulation may obstruct air flow to chimney,
preventing gases to be drawn up the chimney.
Ashes should be collected in a steel container inside the boiler. When container is full it
should be moved outdoors or place on a noncombustible surface.
“Caution” ash tub will be HOT. Gloves will be necessary to remove ash tub from boiler.
Before removing ash tub, turn power to the off position, open ash door. Using a good
pair of gloves remove full ash tub, place tub on a noncombustible surface. Slide an
empty into boiler and turn power switch on.
Other waste shall not be placed or stored in ash containers.
Disposal of ashes: Ashes should be collected in a metal container. When container is
full it should be removed from the boiler and put on a noncombustible surface or the
ground well away from all combustible materials, pending final disposal. If ashes are
disposed of by burial in soil or otherwise locally dispersed, they should remain in the
container until all cinders have cooled thoroughly cooled.
Fire Door and Ash Door must be closed at all times during operation.
Hopper: It is necessary to keep some coal in the hopper while boiler is in operation.
Fuel: Burn Rice or Buck wheat Anthracite coal only.
Safety

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Boiler must be installed on a noncombustible surface (concrete, fireproof floor pad,
ect).
Prolonged Power outages, during a prolonged period of time without power steps
should be taken to ensure that the boiler does not freeze. Circulating the water to
prevent freezing or draining the system before freezing. If have become frozen checks
for breaks in the piping and repair before starting the boiler. If the boiler temperature is
extremely low, boiler controls should be turn down to the lowest settings. Light the fire at
let the system heat up to lowest setting, let circulators run and check system for leaks. If
system is good turn controls to regular settings.

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Hot Water Boiler Specification Charts
Model
No.
BTU / Hour
(Nearest
Thousand)
Hopper
Capacity
(Lbs.)
Stoker Data
Relief Valve
MAX PSI
Net
Gross
Model
# of Grates
(3” x 14”)
KAA-4
102
120
200
AA
3” X 12”
30
KFL-6
116
132
275
AA
3” X 12”
30
KA-6
122
144
275
A
3
30
KB-8
163
192
315
B
4
30
KC-10
204
240
450
C
5
30
KD-12
245
288
525
D
6
30
KE-15
306
360
525
E
7
30
KF-18
367
432
525
F
8
30
KG-22
448
528
585
G
9
30
Model
No.
Gallons
of
Water
Smoke
Outlet
Size
Width
Length
Height
KAA-4
34
6”
22”
34”
47”
KFL-6
55
8”
24”
40”
52-1/2”
KA-6
55
8”
24”
40”
52-1/2”
KB-8
74
9”
29”
42”
55”
KC-10
86
10”
31”
44”
56”
KD-12
96
10”
31”
50”
55”
KE-15
122
12”
33”
55”
57”
KF-18
154
12”
33”
54-1/2”
61”
KG-22
188
14”
37”
62-1/2”
61”
Chimney should be as per NFPA 211- 316 Stainless Steel Liner or Brick Lined and in good
condition, height requirement is 16 feet.
*For Canadian installation: as per NFPA 211- Chimney must be 304, 316, 404, 443 stainless
steel.

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Installation
Boiler Placement
1. Boilers must be installed on a noncombustible floor. Keystoker boilers are available
with fire door on the right or left side. When you stand at the stoker end of theboiler
and look directly over top of boiler toward stack end, you may choose to have a
fire door on the right or left side of boiler. Selecting a position to make this door
accessible is important. When door side must be placed toward a wall, 30”
clearance is recommended for easy fire and ash door access. Clearance from wall
at stack end should be 18” to permit removal of water heating coil if necessary and
easy access for removal and cleaning of stack pipe. Clearance on blank and hopper
sides should be 6”. Clearance from the top of the boiler to a combustible is 12”. Refer
to Figure 1. For industrial and commercial installations please follow localcodes.
Requirement for combustible floor protection. 16” in front of fire/ash door 8” on
each side of doors. At least 2” on either side a chimney connector.
FIGURE 1

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Setup of Boiler
1. Place boiler in desired position.
2. Place steel shims or bricks under each corner of boiler to allow an air space, to
prevent moisture from accumulating and rusting base of boiler. The brick should
stick out 2” Past each corner so the jacket has adequate support.
3. Using a level, plumb stoker end of the boiler, adding steel shims as necessary.
Failure to do this will change pitch on stoker unit and may have adverse effects
when burning coal.
4. Using a level, check top of boiler from side to side, adding shims as necessary to level
boiler. Do not place shims completely under boiler. Allow 1” to 2” of shims to extend
out from under the boiler. Shims are used as a base to set insulated jacket upon.
Chimney should be as per NFPA 211- 316 Stainless Steel Liner or Brick Lined and in good
condition, height requirement is 16 feet.
*For Canadian installation: as per NFPA 211- Chimney must be 304, 316, 404, 443 stainless
steel.
Supply & Return Piping System
The top of the boiler has at least 4 openings. The largest opening is the feed line to
your radiation. Since this outlet has a drop tube welded inside the boiler, you must
use for your radiation supply line. Even though it may be necessary to reduce down
to a smaller size, we recommend starting with 1 ¼” pipe and installing a
1 ¼” x 1 ¼” x 1” tee in supply line to be used for a by-pass loop. You may now make
your piping connections from feed outlet on boiler to flow valve.
You may use either of the large openings on the bottom of the stack end of the boiler as
your return. Select the side that will allow convenient access to the circulator for future
servicing. Install return piping and circulator, again referring to the location of by-pass loop.
The 1 ¼” x 1 ¼” x 1” tee must be installed below circulator. Refer to Diagram 1, page 25. The
circulator can be mounted to the feed line to push the water, instead of pulling the water if
it was installed on the return line.
Install by-pass loop as per ISO Plumbing Diagrams, page 24, with 1” pipe size. Place a tee,
1” x ½” F x 1”, in by-pass loop allowing the immersion well, for the 4006B Honeywell Hi-Limit
control, to extend into the full-water flow after its installed.
Over 50 years of installation experience has proven to us that the above-mentioned by-
pass loop is absolutely necessary for optimum performance of your heating system
Install a boiler drain valve in the other large opening at bottom of boiler.
Boiler Fill & Domestic Water Piping
1. Refer to Diagram 1, Pg. 28. Install ½” male adaptors in both fittings on domestic
water coil.
2. Install a ½” male adaptor onto the ½” fittings on the top of the end of the boiler to
be used for a boiler water fill.

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3. Solder a piece of pipe onto the ½” adaptor to extend the pipe outside of the jacket.
NOTE: Before proceeding with connections for piping of boiler fill and domestic water,
INSTALL stack end of insulated steel jacket NOW. Then you may proceed with completion of
domestic piping and installation of necessary valves.
4. Install a domestic water mixing valve, Honeywell AM-1 series not included with boiler.
Install as per manufacture instructions.
5. Automatic fill valve is not supplied, install as per manufactureinstructions.
6. Install a PH 5 expansion tank on the cold-water line as per manufacturer instructions.
Installation & Piping of Accessories
1. A ¾” 30 lb. ASME approved relief valve (supplied) must be installed in ¾” fitting on top of
boiler, turning discharge to the side and hard pipe it to 6” above floor. End of relief valve
discharge pipe should be cut on an angle so no valves, caps or plug can be installed.
Discharge pipe must be open-ended.
2. Install altitude gauge (temperature/ pressure gauge) (supplied)
3. Connect expansion tank directly to remaining fittings on top of the boiler, NOT to any
other part of the heating system. Install a 1/2” ball valve in pipe going to expansion tank
with direction marker on valve pointing toward the expansion tank. If an air scoop is
used, you must have an air bleeder on top of the boiler.
4. Install immersion wells for the (2) high limit controls and (1) for the triple aqua stat, in ¾”
fittings on side of boiler above fire door. (supplied). Install the triple aqua stat well
closest to the hopper. The triple aqua stat well has an insulated probe for the low water
cutoff. Refer to figure 5 Pg. 21.
5. Apply Hi-temperature silicone or furnace cement to the boiler where the fire door frame
is going to seal against. Then place fire door into boiler opening and secure bytightening
handle open and put it through hole in handle on fire door and squeezing it closed.
Jacket & Stoker Installation
1. Install hopper end of jacket, then blank side, then fire door side; secure with #8 x 1” sheet
metal screws provided. Install jacket top; secure with #8 x 3/8” sheet metalscrews.
2. Stoker units are shipped pre-assembled; bottom of a stoker has a ¼” rod welded in place
which must go inside the stoker opening. Place a thick smear of furnace cement or high
temp silicone on flange of stoker and lift into place, securing with 3/8 x 1 ¼” square-
headed bolts, washers, and nuts as provided. Insert bolts from the inside towards the
outside. Install nuts on the outside for easy removal.
3. Set hopper into place. The hopper bottom should overlap stoker throat approximately 1”.
Since one hopper is used for varying sized stokers, it may be necessary to trim the

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opening. Bend flange down to fit inside throat of stoker –be sure mechanism is free to
operate.
Control Installation & ElectricalWiring
1. Install triple aqua stat onto its well being careful not to pinch the wire for connection.
2. Install limit switches onto the remaining (2) wells. Taking care not to damage the
sensor probes.
3. After tightening triple aqua stat to well, connect well wire to terminal on circuit board.
Your stoker must be on its own circuit. From main breaker to boiler use 14-2 wire with
ground on a 15-amp breaker. Follow wiring diagram and any applicable UL and
local code. Use copper conductors only.
Stack Pipe & Draft Control Installation
1. Stack pipe may now be connected from boiler to chimney, using as few elbows as
possible. If stack pipe must be reduced in size, reduce stack at the chimney. It is
important to run full size stack from boiler to chimneythimble.
2. Install barometric draft controls in first full section of stack closest to boiler. Follow
instructions packed with draft control, making sure the draft control bearing are level
and face of draft control is perpendicular to floor. Stack pipe must be 18” from any
combustible material. In US it can be 26 gauge galvanized, or 26 gauge black stack
pipe.
*For Canadian installation: Chimney must be 304, 316, 404, 443 stainless steel.
Initial Startup –Water Filling
1. Fill system by opening boiler feed valve.
2. Open air vents on radiation one at a time until air is removed from system. Normal
operating pressure on most heating systems is between 10 and 20 PSI. Automatic fill
valves are factory set at 12 PSI. If an automatic fill valve is not used, then boiler feed
valve must remain in normally closed position.
3. Open valve supplying water to domestic hot water coil, this valve must remain in the
normally open position.
4. After bleeding off the system is complete, open valve supplying water to expansion
tank, this valve must remain in the normally openposition.
Fuel Type
1. Burn rice or buck sized Anthracite coal only.
Danger risk of fire or explosion. Do not burn garbage, gasoline, drain oil, or other flammable
liquids. Do not use chemicals or fluids to start fire.

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Operation
Startup
1. To start a fire, fill hopper with coal, reach in through fire door and pull coal down to
cover entire grate area. Place kindling (charcoal supplied) into a full sheetof
newspaper, crumble paper, and dig kindling deep into coal in the center of grate.
Light newspaper with match and turn switch on. NEVER USE GASOLINE OR LIGHTER
FLUID TO START FIRE. When kindling is burning well, place a few small shovels full of
coal onto the fire.
Check Draft After Fire Startup
1. Allow boiler and chimney to warm up.
2. Insert draft gauge through pre- drilled hole in upper portion of firedoor. See figure 6,
Page 22.
3. Open air shutter (located on bottom of scroll between stoker motor and gear box
about ½”.
a. With the stoker motor running and feeding coal adjustthe barometric
damper until draft gauge reads (-.02) inches of water column.
b. If draft is less than a (-.02) inches of water column draft with thebarometric
damper closed, you must close the air shutter (between gear box & stoker
motor) a little and recheck.
c. Repeat until you obtain a (-.02) inches of water column.
d. If the draft is higher than (-.02) inches of water column you must adjust the
barometric draft regulator or main combustion air could be opened to
allow more air into the fire chamber.
e. Move the weight on barometric regulator left or right to obtain the (-.02)
inches of water column re-check the draft until you obtain a (-.02) inches of
water column.
Initial Coal Feed
1. Advance RED nut all the way forward.
2. Adjust for coal type
a. Turn the RED nut counter clockwise 11 or 12 turns for burning ricecoal.
b. Turn the RED nut counter clockwise 9 or 10 turns for burning buck wheat coal.
3. When boiler is running for about an hour under full load grates should have about 2”
of dead ash before falling into the ash pan. If not fine tune coal feed adjuster RED nut
to obtain optimum setting.
4. Refer to Diagram 1 (Continuous Operation) and Diagram 2 (IntermittentOperation)

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Diagram 1 –Continuous Operation
Depicts what fire should look like when the boiler calls for heat for extended period:
A. Unburned fresh coal supply from coal hopper
B. Burning Coals
C. Ash on lower end of grate (around 2”)
The actual length of burning coals will vary as boiler demand increases or decreases. If
burning coals fall off grate, reduce coal feed by turning RED adjustment nut in a counter
clock-wise direction 1 or 2 full turns. Wait at least 1 hour before making any more
adjustments.
When the boiler is calling for heat, the large stoker motor will run continuously, but if the fire
bed remains small, increase the coal feed by turning RED adjustment nut clock-wise.
Under normal draft conditions, when fire bed has reached its maximum length (with 2” of
ash) flames should be touching top of interior boiler plate. If flame is not reaching top of
boiler:
1. Fire bed may be too thick.
2. Reduce coal feed.
3. Burrs may be stuck on grate, scrape grate until it issmooth.
4. Not enough air flow, adjust air intake shutter on stoker unit.
(see Check Draft section).
C.
ASH
B.
FIRE A.
UNBURNED
COAL
DIAGRAM 1

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Diagram 2 –Intermittent Operation
Depicts what fire size should look like when the boiler has not called for heat for
extended periods:
A. Unburned fresh coal supply from hopper.
B. Burning coal (about 1-1 ½” to 2”) (little to noflames).
C. Ash on lower end of grate
B.
FIRE A.
UNBURNED
C.
ASH
COAL
DIAGRAM 2

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Initial Main Combustion Air Setting
The initial main combustion air setting is open about 1/2'’ may have to be adjusted with draft
gauge. Refer to Figure 2.
Combustion Blower Operation & Adjustment
To obtain a more complete burn out of coal during an idle fire, a small secondary blower
motor is attached to the stoker unit. Setting of secondary combustion air 1/3 of the way
open. THIS MOTOR IS DESIGNED FOR CONTINUOUS RUN.
1. When large stoker motor is running on demand, small blower will assist with
combustion and heat output, by producing a more intense and hotter fire.
2. When demand cycle is completed, large stoker motor will shut off, and small
secondary motor will continue to run. This will cause the coal that is already on the
grate to burn, rather than to allow coal to smolder and die out in an unburned
condition. This will achieve a cleaner ash, and allow more heat to be produced and
absorbed into heating system.
3. During summer operation, the small combustion motor will force a small amount of air
through grates at all times, which will cause the ash to become like powder. It also
prevents the fire from going out. At the same time, it reduces the size of fire bed to
approximately 1 ½” to 2” which will prevent boiler water from becoming overheated.
4. Proper sizing of fire is obtained by turning red nut on feed control arm. Clockwise
(CW) for more coal feed and Counterclockwise (CCW) for less coal feed.
5. Location and final placement for red nut will be determined by size of coal you
purchase. For rice coal, red nut might be turned down 12 turns for maximum
setting, where, as for buckwheat coal, red nut might only be turned down 10 turns
from maximum setting.
Combustion Air
Setting
FIGURE 2

Keystoker –Schuylkill Haven, PA 17972
Hot Water Boilers
© July 2019 Rev 02
- 19 -
6. During winter operation, hot coals should never be pushed off end of grate. This
would indicate that the coal feed needs to be reduced (CCW) or if during winter
operation; fire bed is too small, turn red the nut (CW) toincrease.
7. After coal feed adjustment is completed, if during summer, the water is too hot…DO
NOT ADJUST COAL FEED. First reduce timer only. If fire goes out…DO NOT ADJUST
COAL FEED. Increase timer only. If changing the timer does not solve the problem,
then adjust 1 to turn off the coal feed.
Component Descriptions & Operation
Boiler Unit Components
1. Stoker Body
2. Side Rail Left K-2C
3. Side Rail Right K-1C
4. Grate K-15-1-L
5. Grate K-15-2-L
6. Grate K-15-3-L
7. Grate K-15-4-L
8. Motor
9. Blower Rotor
10. Bearing K-19
11. Throat Strap K-18
12. Pusher Bar Drive Yolk K-8-BC
13. Pusher Bar K-9-BC
14. Pusher Bar Drive Shaft
15. Bearing K-17
16. Feed Crank K-7
17. Feed Assembly Connector K-6
18. Feed Arm Nut
19. Feed Arm Adjustment Nut
20. Feed Latch K-12
21. Feed Spring
22. Feed Bolt
23. Drive Wheel K-5
24. Gearbox K-14
25. Coupling
26. Secondary Combustion Blower
FIGURE 3

Keystoker –Schuylkill Haven, PA 17972
Hot Water Boilers
© July 2019 Rev 02
- 19 -
Boiler Unit Components –cont’d
FIGURE 4