Crown Boiler KSZ Series User manual

KSZ Series
Oil-Fired Steam Boilers
INSTALLATION INSTRUCTIONS
These instructions must be axed on or adjacent to the boiler
Models:
• KSZ065
• KSZ075
• KSZ100
• KSZ090
• KSZ125
• KSZ150
• KSZ120
• KSZ175
• KSZ200
DESIGNED TO LEAD
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage,
injury, or loss of life. For assistance or additional information, consult a qualied installer, service
agency or the gas supplier. This boiler requires a special venting system. Read these instructions
carefully before installing.
980280 Rev F, 03-18
Crown Boiler Company
P.O. Box 14818
3633 I Street
Philadelphia, PA 19134
www.crownboiler.com

2

1
IMPORTANT INFORMATION - READ CAREFULLY
The following terms are used throughout this manual to bring attention to the presence of hazards
of various risk levels, or to important information concerning product life.
DANGER
Indicates an imminently hazardous situation which,
if not avoided, will result in death, serious injury or
substantial property damage.
WARNING
Indicates a potentially hazardous situation which, if
not avoided, could result in death, serious injury or
substantial property damage.
CAUTION
Indicates a potentially hazardous situation which, if
not avoided, may result in moderate or minor injury
or property damage.
NOTICE
Indicates special instructions on installation,
operation, or maintenance which are important but
not related to personal injury hazards.
NOTICE
This boiler has a limited warranty, a copy of which is included with this boiler.
The warranty for this boiler is valid only if the boiler has been installed, maintained and operated in
accordance with these instructions.
Surface rust on cast iron sections may be attributed to the manufacturing process as well as condensation
during storage. Surface rust is normal and does not a󰀨ect the performance or longevity of a boiler.
All boilers must be installed in accordance with National, State and Local Plumbing, Heating
and Electrical Codes and the regulations of the serving utilities. These Codes and Regulations
may dier from this instruction manual. Authorities having jurisdiction should be consulted
before installations are made.
In all cases, reference should be made to the following Standards:
USA BOILERS
A. Current Edition of American National Standard ANSI/NFPA 31, “Installation of Oil
Burning Equipment”, for recommended installation practices.
B. Current Edition of American National Standard ANSI/NFPA 211, “Chimneys, Fireplaces,
Vents, and Solid Fuel Burning Appliances”, For Venting requirements.
C. Current Edition of American Society of Mechanical Engineers ASME CSD-1, “Controls and
Safety Devices for Automatically Fired Boilers”, for assembly and operations of controls
and safety devices.
D. All wiring on boilers installed in the USA shall be made in accordance with the National
Electrical Code and/or Local Regulations.
CANADIAN BOILERS
A. Current Edition of Canadian Standards Association CSA B139, “Installation Code for Oil
Burning Equipment", for recommended Installation Practices.
B. All wiring on boilers installed in Canada shall be made in accordance with the Canadian
Electrical Code and/or Local Regulations.

2
DANGER
DO NOT store or use gasoline or other ammable vapors or liquids in the vicinity of this or any other appliance.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal
injury or loss of life. Failure to follow all instructions in the proper order can cause personal injury or
death. Read and understand all instructions, including all those contained in component manufacturers
manuals which are provided with the boiler before installing, starting-up, operating, maintaining or servicing
this boiler. Keep this manual and literature in legible condition and posted near boiler for reference by
owner and service technician.
This boiler requires regular maintenance and service to operate safely. Follow the instructions contained
in this manual.
Installation, maintenance, and service must be performed only by an experienced, skilled and knowledgeable
installer or service agency.
All heating systems should be designed by competent contractors and only persons knowledgeable in
the layout and installation of hydronic heating systems should attempt installation of any boiler.
Installation is not complete unless a safety valve is installed into rear section boss, at the back of rear
section per Figure 8.1 located in Section VIII, “System Piping” of this manual.
It is the responsibility of the installing contractor to see that all controls are correctly installed and are
operating properly when the installation is completed.
This boiler is not suitable for direct installation on combustible ooring. See Figure 3 for means of
installing boiler over a combustible oor. Do not install boiler on carpeting.
Do not tamper with or alter the boiler or controls.
Inspect ueways at least once a year - preferably at the start of the heating season. The inside of
the combustion chamber, the vent system and boiler ueways should be cleaned if soot or scale has
accumulated.
When cleaning this boiler, take precaution to avoid damage to burner swing door insulation. If damaged,
or if there is evidence of previous damage, burner swing door insulation must be replaced immediately.
Oil Burner and Controls must be checked at least once a year or as may be necessitated.
Do not operate boiler with jumpered or absent controls or safety devices.
Do not operate boiler if any control, switch, component, or device has been subject to water.
Appliance materials of construction, products of combustion and the fuel contain alumina, silica, heavy
metals, carbon monoxide, nitrogen oxides, aldehydes and/or other toxic or harmful substances which
can cause death or serious injury and which are known to the state of California to cause cancer, birth
defects and other reproductive harm. Always use proper safety clothing, respirators and equipment when
servicing or working nearby the appliance.

3
FOLLOW ALL INSTRUCTIONS and warnings printed
in this manual and posted on the boiler.
INSPECT THE BOILER, BURNER AND CONTROLS
ANNUALLY. To keep your boiler safe and e󰀩cient,
have a service technician follow the Service
checklist near the end of this manual.
IF YOU ARE NOT QUALIFIED to install or service
boilers, do not install or service this one.
THE BOILER MAY LEAK WATER at the end of its
useful life. Be sure to protect walls, carpets, and
valuables from water that could leak from the boiler.
PROTECT YOUR HOME IN FREEZING WEATHER.
A power outage, safety lockout, or component
failure will prevent your boiler from lighting. In
winter, your pipes may freeze and cause extensive
property damage. Do not leave the heating system
unattended during cold weather unless alarms
or other safeguards are in place to prevent such
damage
DO NOT BLOCK AIR FLOW into or around the boiler.
Insu󰀩cient air may cause the boiler to produce
carbon monoxide or start a re.
KEEP FLAMMABLE LIQUIDS AWAY from the boiler,
including paint, solvents, and gasoline. The boiler
may ignite the vapors from the liquids causing
explosion or re.
KEEP CHILDREN AND PETS away from hot surfaces
of the boiler, boiler piping, and vent pipe.
CARBON MONOXIDE (CO) is an odorless, deadly
gas that may be introduced into your home by
any malfunctioning fuel-burning product or vent
system failure. Consider installing CO alarms near
bedrooms in all levels of the building to warn you
and your family of potential CO exposure.
READ THIS ENTIRE MANUAL before attempting
installation, start-up, or service. Improper
installation, adjustment, alteration, service, or
maintenance may cause serious property damage,
personal injury, or death.
DO NOT DISCONNECT PIPE FITTINGS on the boiler
or in the heating system without rst verifying that
the system is cool and free of pressure and that
your clothing will protect you from a release of hot
water or steam. Do not rely solely on the boiler’s
temperature and pressure gauge when making this
judgment.
USE PROPER PERSONAL PROTECTION
EQUIPMENT when servicing or working near the
boiler. Materials of construction, ue products, and
fuel contain alumina, silica, heavy metals, carbon
monoxide, nitrogen oxides, and/or other toxic or
harmful substances that can are hazardous to
health and life and that are known to the State of
California to cause cancer, birth defects, and other
reproductive harm.
INSTALL ALL GUARDS, cover plates, and
enclosures before operating the boiler.
SIZE THE BOILER PROPERLY relative to the design
heat load or, if using domestic hot water priority,
the peak hot water load, whichever is larger. A
grossly oversized boiler will cycle excessively and
this will lead to premature failure of the boiler and
its components. Our warranty does not apply to
damage from excessive cycling.
ADHERE TO ALL LOCAL CODE REQUIREMENTS.
Contact your local code inspector prior to
installation. In the absence of a local code, adhere to
the latest editions of the Installation of Oil Burning
Equipment ANSI/NFPA 31 in the USA or CAN/CSA
B139, Installation Code for Oil Burning Equipment in
Canada.
ALL WIRING must comply with the National
Electrical Code ANSI/NFPA 70 (in the USA) or the
Canadian Electrical Code CSA C22.1 (in Canada)
and any local regulations.
WARNINGS FOR THE HOMEOWNER
WARNINGS FOR THE INSTALLER

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Table of Contents
I. Product Description ............................................................................... 5
II. Specications ......................................................................................... 5
III. Before Installing .................................................................................... 6
IV. Locating the Boiler ................................................................................ 7
V. Air for Combustion & Ventilation ......................................................... 9
VI. Venting ................................................................................................... 13
VII. System Piping ........................................................................................ 15
VIII. Indirect & Tankless Water Heater Piping ............................................... 17
IX. Fuel Line Piping .................................................................................... 20
X. Wiring .................................................................................................... 23
XI. Start-Up & Checkout ............................................................................. 27
XII. Service & Maintenance .......................................................................... 30
XIII. Parts ....................................................................................................... 34
WARNING
This boiler contains very hot water under high pressure. Do not unscrew any pipe ttings nor attempt
to disconnect any components of this boiler without positively assuring the water is cool and has no
pressure. Always wear protective clothing and equipment when installing, starting up or servicing this
boiler to prevent scald injuries. Do not rely on the pressure and temperature gauges to determine the
temperature and pressure of the boiler. This boiler contains components which become very hot when
the boiler is operating. Do not touch any components unless they are cool.
This boiler must be properly vented. The chimney must be inspected for any obstructions and cleaned
prior to each heating season. A clean and unobstructed chimney ue is necessary to produce the minimum
draft required to safely evacuate noxious fumes that could cause personal injury or loss of life. Evidence
of loose debris and or condensate induced stains at the base of the chimney ue, connector or smokepipe
joints may be signs of condensing ue gases. Flue gas condensate is corrosive, which requires special
consideration and must be addressed immediately. Refer to Section VII, "Venting” for more details.
This boiler needs fresh air for safe operation and must be installed so there are provisions for adequate
combustion and ventilation air.
This boiler is supplied with controls which may cause the boiler to shut down and not re-start without
service. If damage due to frozen pipes is a possibility, the heating system should not be left unattended in
cold weather; or appropriate safeguards and alarms should be installed on the heating system to prevent
damage if the boiler is inoperative.
This boiler is designed to burn No. 2 fuel oil only. Do not use gasoline, crankcase drainings, or any oil
containing gasoline. Never burn garbage or paper in this boiler. Do not convert to any solid fuel (i.e.
wood, coal). Do not convert to any gaseous fuel (i.e. natural gas, LP). All ammable debris, rags, paper,
wood scraps, etc., should be kept clear of the boiler at all times. Keep the boiler area clean and free of
re hazards.
All boilers equipped with burner swing door have a potential hazard which, if ignored, can cause severe
property damage, personal injury or loss of life. Before opening swing door, unplug burner power cord
from receptacle located on the jacket front panel just above the burner and turn o󰀨 service switch to
boiler to prevent accidental ring of burner outside the combustion chamber. Be sure to tighten swing
door fasteners completely when service is completed.

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I Product Description
The KSZ series boiler is a cast iron oil-red low pressure steam boiler designed for use in closed heating systems. This
boiler must be vented by natural draft into a lined masonry or metal chimney, or Type L vent. An adequate supply of air for
combustion, ventilation and dilution of ue gases must be available in the boiler room. This boiler has connections for use
with an indirect domestic water heater.
The KSZ series boilers are not designed for use in process or other “open” steam systems.
II Specications
FIGURE 1: GENERAL CONFIGURATION

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TABLE 1a: GENERAL SPECIFICATIONS
Notes:
1. Net Ratings are based on piping and pick-up allowances of 1.333.
2. Burner Capacity Rating, GPH is based on #2 oil with a Gross Heating
Value equal to 140000 BTU/Gal.
3. Maximum Working Pressure, Steam -15 PSI.
4. Tankless heater ratings based on 40F inlet water, 140F outlet water, and 190F
boiler water. Ratings are also based on 5 minute intermittent draws with 10 minutes
between draws.
III Before Installing
1) Safe, reliable operation of this boiler depends upon installation by a professional heating contractor in strict accordance
with this manual and the requirements of the authority having jurisdiction.
• In the absence of an authority having jurisdiction, installation must be in accordance with this manual and the latest
edition of Installation of Oil Burning Equipment (ANSI/NFPA31).
• Where required by the authority having jurisdiction, this installation must conform to the latest edition of Standard for
Controls and Safety Devices for Automatically Fired Boilers (ANSI/ASME CSD-1).
2) Make sure that a properly sized chimney is available which is in good condition. Consult the authority having
jurisdiction, Part VI of this manual, and ANSI/NFPA31 for additional information on venting requirements.
3) Make sure that the boiler is correctly sized. Use an industry accepted sizing method such as the I=B=R Guide RHH
published by the Air-Conditioning, Heating and Refrigeration Institute (AHRI).
4) In some cases, boilers installed at altitudes above 2000ft may require a dierent burner conguration from that at sea level.
Consult the local Crown representative for more information.
TABLE 1b: TANKLESS HEATER RATINGS
(GAL/HR) (MBH) (Sq. ft) (MBH)
1.25
1.50
1.20
1.75
2.00
KSZ175
KSZ200
"B" "C"
BURNER
INPUT
0.65
0.75
1.00
83.1
85.4KSZ120
KSZ065
KSZ075
KSZ100
KSZ090
KSZ125
KSZ150
79
"A"
85.1
84.5
83.5
85.0
84.2
90
119
HEATING
CAPACITY
NET AHRI RATING,
STEAM AFUE %
DIMENSIONS (in.)
0.90
8 5/16 6
733
110
149
177
147
207
235 176
246
283
370
346
467
554
458
646
89
83
112
133
110
155
17-3/8
17-3/8
22-3/8
27-3/883.1
82.9 27-3/8
10 13/16 7
17-3/8 8 5/16 6
8 5/16 6
27-3/8 13 5/16 8
22-3/8 10 13/16 7
22-3/8
10 13/16 7
13 5/16 8
13 5/16 8
NUMBER
OF
SECTION
S
3
3
3
4
4
4
5
5
5
KSZ SPACE HEATING RATINGS
BASIC BOILER
MODEL
59
68
MODEL RATING (gpm)
KSZ065 2.25
KSZ075 2.25
KSZ100 2.50
KSZ090 2.50
KSZ125 2.75
KSZ150 3.00
KSZ120 2.75
KSZ175 3.25
KSZ200 3.50

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IV Locating the Boiler
1) Clearances:
• Observe the minimum clearances shown below. Except as noted, these clearances apply to all combustible con-
struction, as well as noncombustible walls, ceilings and doors. Also see Figure 2.
Front – 24”
Left Side – 6” (24” for Boilers Equipped with Float Type Low Water Cut-os)
Right Side – 6” (24” for Boilers Equipped with Tankless Heaters)
Rear – 6” (24” for boilers connected to indirect water heaters)
Top – 6”
Single Wall Chimney Connector (to combustible construction) - 18”
• A 24” service clearance from the jacket is recommended from the top of the boiler. This clearance may be
reduced to that shown above; however, servicing the boiler will become increasingly dicult as this clearance
is reduced.
CAUTION
As with all oil-fired appliances, “Power Venting” this boiler creates a number of potential
problems, especially when this is done through a side wall. These include, but are not
necessarily limited to:
• Accelerated rate of soot buildup on the oil burner cad-cell, burner head, and/or in the
boiler itself.
• Odor complaints
• Severe damage to the side of the structure in the event that the boiler operates at a high
smoke level.
These problems can occur for many reasons, some of which are out of the control of both the
installer and the appliance manufacturer. The use of a chimney to vent this boiler is therefore
recommended. If a power venter must be used, it is the responsibility of the installer and power
venter manufacturer to “engineer” the power vent system. CROWN BOILER CO. WILL ASSUME
NO RESPONSIBILITY FOR DAMAGE TO SIDING, ETC. FROM A POWER VENTED OIL-FIRED
BOILER. THIS APPLIES REGARDLESS OF THE CAUSE OF THE SOOTING.
CAUTION
Fuel oil used with this boiler must conform to ASTM D396. The ASTM D396 standard sets a
5% limit on biodiesel concentration, requires that the biodiesel feedstock comply with ASTM
D6751, and also specifies the procedure that must be used to blend the biodiesel feedstock
with the #2 fuel oil. Attempts to use biodiesel blends not meeting all ASTM D396 requirements
may result in unreliable operation or severe property damage.
WARNING
Failure to observe the following location requirements could result in property damage, a fire,
explosion or carbon monoxide (CO) hazard.

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FIGURE 3: INSTALLATION OVER A COMBUSTIBLE FLOOR
FIGURE 2: CLEARANCES
• A 24” service clearance is required on the left side of KSZ series boilers equipped with oat type low water cut-
os. This is to facilitate low water cut-o maintenance.
2) If listed Type L vent is used, follow vent pipe manufacturer recommendations for minimum clearances.
3) Do not install this boiler directly on a combustible surface. Where it is desired to install the KSZ over a non-carpeted com-
bustible surface, install the boiler on the base shown in Figure 3.
4) Do not install this boiler in a location where gasoline or other ammable vapors or liquids will be stored or used. Do not
install this boiler in an area where large amounts of airborne dust will be present, such as a workshop.

9
V Air for Combustion and Ventilation
Sucient fresh air must be supplied for combustion and ventilation. Provisions for combustion and ventilation air for oil
burning equipment must be made in accordance with Section 1.5, Air for Combustion and Ventilation, in the latest edition of
Installation of Oil Burning Equipment (ANSI/NFPA 31).
To ensure an adequate supply of air for combustion, ventilation and ue gas dilution, start by determining whether the
boiler is to be installed in a building of unusually tight construction. A building of unusually tight construction can be dened
as having one of the following features:
• Walls and ceilings exposed to outside atmosphere have a continuous water vapor retarder with a rating of 1 perm or
less with openings gasketed and sealed.
• Weather stripping has been added on openable windows and doors.
• Caulking and sealants are applied to areas such as joints around window and door frames, between sole plates and
oors, between wall-ceiling joints, between wall panels, at penetrations for plumbing, electrical, and gas lines, and
at other openings.
For Buildings of Other than Unusually Tight Construction
1) Determine whether the boiler is to be installed in a conned space - A conned space is dened as having a volume less
than 50 cubic feet per 1000 BTU/hr input of all appliances installed in that space. To determine whether the boiler room is a
conned space:
a. Total the input of all appliances in the boiler room in thousands of BTU/hr. Round the result to the next highest
1000 BTU/hr.
b. Find the volume of the room in cubic feet. The volume of the room in cubic feet is:
Length (ft) x width (ft) x ceiling height (ft)
In calculating the volume of the boiler room, consider the volume of adjoining spaces only if no doors are installed
between them. If doors are installed between the boiler room and an adjoining space, do not consider the volume of
the adjoining space, even if the door is normally left open.
c. Divide the volume of the boiler room by the input in thousands of BTU/hr. If the result is less than 50, the boiler
room is a conned space.
Example:
A KSZ090 and a water heater are to be installed in a room measuring 6 ft - 3 in x 7 ft with an 8 ft ceiling. The water
heater has an input of 30000 BTU/hr:
Input of KSZ090 = 0.90 Gal/hr x 140000 BTU/Gal = 126000 BTU/hr
Total input in thousands of BTU/hr = (126000 BTU/hr + 30000 BTU/hr)/1000 = 156
Volume of room = 6.25 ft x 7 ft x 8 ft = 350 ft3
350/156 = 2.24. Since 2.24 is less than 50, the boiler room is a conned space.
WARNING
• Insufficient combustion air supply may result in the production and release of soot or
deadly carbon monoxide (CO) into the home which can cause property damage, severe
personal injury or death.
• This boiler is not designed for use in a space that is depressurized relative to the outdoors.
Operating this boiler in a depressurized space may cause property damage, severe
personal injury or death.

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FIGURE 4: BOILER INSTALLED IN CONFINED SPACE,
ALL AIR FROM INSIDE
2) Unconned Space - Natural inltration into the boiler room will normally provide adequate air for combustion and venti-
lation without additional louvers or openings into boiler room.
3) Conned Space - Provide two openings into the boiler room, one near the oor and one near the ceiling. The top edge of
the upper opening must be within 12” of the ceiling and the bottom edge of the lower opening must be within 12” of the oor
(Figure 4).
• Each opening must have a free area of 1 square inch per 1000 BTU/hr input of all fuel burning appliances in the boiler
room. The minimum opening dimension is 3 inches. Minimum opening free area is 100 square inches per opening.
• If the total volume of both the boiler room and the room to which the openings connect is less than 50 cubic feet per
1000 BTU/hr of total appliance input, install a pair of identical openings into a third room. Connect additional rooms
with openings until the total volume of all rooms is at least 50 cubic feet per 1000 BTU/hr of input.
• The “free area” of an opening takes into account the blocking eect of mesh, grills, and louvers. Where screens are
used, they must be no ner than ¼” (4 x 4) mesh.
For Buildings of Unusually Tight Construction:
1) Openings must be installed between the boiler room and the outdoors or a ventilated space, such as an attic or crawl
space, which communicates directly with the outdoors.
2) Two openings are required. The top edge of the upper opening must be within 12 inches of the ceiling. The bottom
edge of the lower opening must be within 12 inches of the oor.
3) Size openings and ducts as follows:
• Vertical ducts or openings directly outdoors (Figure 5, Figure 6, and Figure 7) - Each opening must have a free
cross sectional area of 1 square inch per 4000 BTU/hr of the total input of all fuel red appliances in the boiler
room but not less than 100 square inches. Minimum opening size is 3 inches.
• Openings to outdoors via horizontal ducts (Figure 8) - Each opening must have a free cross sectional area of 1
square inch per 2000 BTU/hr of the total input of all fuel red appliances in the boiler room but not less than 100
square inches. Minimum opening size is 3 inches.
• The “free area” of an opening takes into account the blocking eect of mesh, grills, and louvers. Where screens
are used, they must be no ner than ¼” (4 x 4) mesh.

11
FIGURE 6: ALL AIR FROM OUTDOORS,
VIA VENTILATED ATTIC
FIGURE 5: ALL AIR FROM OUTDOORS, VENTILATED
CRAWL SPACE AND ATTIC

12
FIGURE 8: ALL AIR FROM OUTDOORS, USING
HORIZONTAL DUCTS INTO BOILER ROOM
FIGURE 7: ALL AIR FROM OUTDOORS, USING
OPENINGS INTO BOILER ROOM

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VI Venting
Vent installation must be in accordance with local building codes, or the local authority having jurisdiction.
Typical vent installation is illustrated by Figure 9. The components of vent installation are the vent connector (breeching),
barometric draft regulator, and chimney.
1) Acceptable Chimneys - The following chimneys may be used to vent a KSZ series boiler:
• Listed Type L vent - Install in accordance with the manufacturer’s instructions, the terms of its listing, and applicable
codes.
• Masonry Chimney - The masonry chimney must be constructed in accordance with the latest edition of Standard
for Chimneys, Fireplaces, Vents, and Solid Fuel Burning Appliances (NFPA 211) and lined with a clay liner or other
listed lining system. Do not vent a KSZ series boiler into an unlined chimney.
FIGURE 9: TYPICAL VENT SYSTEM
INSTALLATION AND COMPONENTS
WARNING
• Improper venting may result in property damage and/or the release of flue gases, which
contain deadly carbon monoxide (CO), into the home, which can cause severe personal
injury or death.
• Inspect existing chimney before installing boiler. Failure to clean or replace damaged pipe
or tile lining will cause property damage, severe personal injury or death.

14
2) Acceptable Vent Connectors - The following may be used for vent connectors:
• Listed Type L vent.
• Single Wall Galvanized Pipe - Use 0.018” (26 gauge) or heavier.
3) Chimney and Vent Connector Sizing - See Table 2 for minimum vent connector and chimney sizing. The vent connector
size must not be smaller than the boiler ue collar diameter.
4) Do not vent this appliance into any portion of a mechanical vent system operating under positive pressure.
5) Do not connect the boiler into a chimney ue serving an open replace or other solid fuel appliance.
6) Prior to boiler installation, inspect chimney for obstructions or other defects and correct as required. Clean chimney as
necessary.
7) Vent pipe should slope upward from the boiler not less than one inch in four feet. No portion of vent pipe should run
downward or have sags. Vent pipe must be securely supported.
8) The vertical section of vent pipe coming o the boiler should be as tall as possible, while still maintaining the proper
clearance from the horizontal vent connector to combustibles and the proper pitch called for in (7) above.
9) Vent pipe should be installed above the bottom of the chimney to prevent blockage.
10) Vent pipe must be inserted ush with inside face of the chimney liner and the space between vent pipe and chimney
sealed tight. A thimble permanently cemented in place can be used to facilitate removal of chimney connector for cleaning.
11) Install the barometric draft regulator in accordance with the regulator manufacturer’s instructions.
12) Secure all joints in the vent connector system with sheet metal screws. This includes the joint between the vent
connector and the boiler collar, as well as the barometric draft regulator. Use at least three screws at each joint.
TABLE 2: MINIMUM RECOMMENDED BREECHING AND
CHIMNEY SIZE
Round I.D. (in) Rectangular I.D. (in) Height (ft)
KSZ065 6 6 8 x 8 15
KSZ075 6 6 8 x 8 15
KSZ100 6 6 8 x 8 15
KSZ090 7 7 8 x 8 15
KSZ125 7 7 8 x 8 15
KSZ150 7 7 8 x 8 15
KSZ120 8 8 8 x 8 15
KSZ175 8 8 8 x 8 15
KSZ200 8 8 8 x 8 15
Boiler
Model
Min Breeching
Dia. (inches)
Min. Recommended Chimney Size and Height

15
FIGURE 10: STEAM BOILER PIPING FOR GRAVITY RETURN
Figure 10 shows recommended near boiler Piping for most common types of gravity return steam systems. Additional
information on steam system design may be found in the I=B=R Guide RHH published by the Air-Conditioning, Heating and
Refrigeration Institute (AHRI).
One of the primary purposes of this near boiler piping is to separate tiny water droplets from the steam exiting the boiler
so that “dry” steam is sent to the system. If the near boiler piping is not correct, wet steam will enter the system and the
following problems may occur:
• Short cycling on low water
• Boiler or system Flooding
• Hammering
• Failure to heat one or more radiators
VII System Piping
WARNING
• Install boiler so that the electrical components are protected from water (dripping,
spraying, rain, etc.) During appliance operation and service (circulator replacement,
etc.).
• Operation of this boiler in a system having significant amounts of dissolved oxygen can
cause severe heat exchanger corrosion damage.
• Do not use toxic additives in this system.
• Pipe safety valve discharge to a safe location. The safety valve may discharge steam or
scalding hot water.
• Do not install a valve in the safety valve discharge line.
• Do not move safety valve from factory location.
• Do not plug safety valve discharge. Blocking the safety valve may result in boiler
explosion.

16
Avoid the common piping mistakes shown in Figure 11. This applies even if the existing boiler has one of the piping mistakes
shown in Figure 11 and appears to be working. If two or more steam mains must be connected to the boiler, connect a
separate take-o for each main into the header between the riser(s) and equalizer. Also note the following points:
1) A size reduction must be made to connect the header to the equalizer. This reduction must be made in the vertical equalizer
line. Do not make this size reduction in the horizontal header.
2) One-pipe steam systems require air vents on each radiator, as well as at the end of each main. For the system to work
properly, these vents must be properly installed, sized, and be in good condition. Inspect and replace any defective vents. If
there are no vents at the ends of the mains, install them.
3) Do not attempt to manifold multiple KSZ boilers with gravity returns.
4) For installations with condensate or boiler feed pumps, follow the pump manufacturer’s piping instructions. Such systems
generally do not require Hartford loops.
5) Do not use a check valve in place of, or in addition to, a Hartford loop on a gravity return system.
6) Pipe the ll connection from a clean source of cold water. When the water supply is from a well, make sure that a strainer
is installed in the well system.
Piping Installation
1) Remove parts bag from boiler crate.
2) Install safety valve (spindle must be in vertical position) into the 3/4” tapping on top of the boiler.
3) Pipe the discharge of the safety relief valve to a location where water or steam will not create a hazard or cause property
damage if the valve opens. The end of the discharge pipe must terminate in an unthreaded pipe. If the safety valve discharge
is not piped to a drain, it must terminate at least 6 inches above the oor. The termination of the safety valve discharge piping
must be in an area where it is not likely to become plugged by debris or subjected to freezing.
4) Install drain valve provided into the return piping.
5) Connect system supply and return to boiler. See Figure 10. All KSZ boilers use one supply riser and one return tapping.
FIGURE 11: COMMON NEAR-BOILER PIPING MISTAKES

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VIII INDIRECT & TANKLESS WATER HEATER PIPING
INDIRECT WATER HEATER PIPING
All KSZ series boilers are equipped with tappings to permit the connection of a Crown Mega-Stor, or other indirect water
heater. In this type of system, hot boiler water is drawn from below the water line and passed through the heat exchanger in
the indirect water heater. This section describes boiler-side piping only. Refer to the indirect water heater instruction manual
for domestic water piping. The components in this system and their functions are as follows:
1) Circulator - Mount the circulator as shown in Figure 12A. The circulator should be located as low and as close to the
boiler as practical. Do not install valves, or other devices having a signicant pressure drop, between the boiler and the
circulator inlet. All piping between the boiler and the circulator inlet should be 1”, regardless of the size of the piping
required in the rest of the system. See Figure 17 in Part X for wiring information.
2) “Y” Strainer - Install a “Y” strainer to prevent sediment from accumulating inside the indirect water heater.
3) Check Valve - Prevents gravity circulation through the indirect water heater when the boiler is responding to a call for
heat.
4) Boiler Limit Control - Use a SPST break-on-rise temperature limit control such as the Honeywell L4006A. Do not set
the limit above 180F as doing so may cause the boiler to steam when there is no call for heat. See Figure 17 for wiring
information.
5) Valves and Unions - Install shut-o valves, drain valves, and unions in locations that will facilitate maintenance of the
system. Do not install any valves between the boiler and circulator inlet.
FIGURE 12a: INDIRECT WATER HEATER BOILER-SIDE PIPING

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2) Flow Restrictor (Recommended) - If water is drawn from the tankless coil at a rate in excess of the rating in Table 1b,
the temperature of the hot water may be too low to be of use. The use of a ow restrictor will prevent this problem by
limiting the rate at which water can pass through the tankless heater. If a restrictor is used, select one having a rating
in GPM approximately equal to the rating shown in Table 1b. If possible, locate this restrictor at least 3 feet from the
tankless heater inlet so that it is not subjected to excessive temperatures when no water is owing through the coil.
3) Pressure Relief Valve (Required) - Limits the pressure in the tankless heater and piping. Use an ASME constructed valve
designed for domestic water service, such as the Watts #3L. Note that this is a pressure relief valve, not a T&P valve.
Select a valve with a pressure setting less than or equal to the working pressure marked on the tankless coil. Pipe the
discharge to a safe location using piping the same size as the discharge connection on the valve.
4) Hose Bib Valves (Recommended) - These valves permit the coil to be periodically “backushed” to remove sediment.
TANKLESS HEATER PIPING
KSZ Series boilers equipped with tankless heaters are supplied with a Honeywell L4006A limit control and a 3/4 NPT
well. For shipping purposes, these components are shipped unmounted. This control is mounted in the 3/4 tapping in the
center of the tankless coil.
Make the piping connections to the coil before installing the L4006A. When making the “OUT” connection, make sure
that the piping is routed so that it will not interfere with the L4006A.
Pipe the heater as shown in Figure 12b. The components in this system and their functions are as follows:
1) Tempering Valve (Required) - During the heating season, the water exiting the tankless heater may be 180 degrees or
more. The mixing valve blends hot water leaving the tankless heater with cold water so as to maintain the hot water
supplied to the xtures at a xed temperature. This saves energy, increases the amount of usable hot water available to
the homeowner, and reduces the risk of scalding.
Install a mixing valve with a setting range of approximately 110 to 130F. Follow the manufacturer’s instructions for
installing this valve. Usually a “heat trap” will be required between the coil and the “hot” connection on the mixing
valve.
IMPORTANT
• Some indirect water heaters may not be suitable for use with a steam boiler. Consult the
water heater manufacturer’s guidelines before installing it in this type of system.
• Boiler water temperatures and flow rates in this type of system may be considerably lower
than those upon which the water heater manufacturer’s ratings are based. This may result
in substantially longer water heater recovery times.
DANGER-SCALD HAZARD
The control supplied with this boiler is not intended to provide accurate control of the
domestic water temperature leaving the tankless heater. An installer supplied, ASSE 1017
or ASSE 1070 certified tempering valve is therefore REQUIRED as part of this boiler’s
installation.
• Select, and install tempering valve in accordance with the valve manufacturer’s
instructions and applicable local codes. In the absence of such codes follow the
Uniform Plumbing Code (IAPMO/UPC-1). Also note that additional tempering valves
may be required at the fixtures themselves.
• Adjust low limit and tempering valve to the lowest practical setting.
• Feel water before showering or bathing.