HydroTherm KN SERIES Manual

IOMKN2-508
IN UNITED STATES: 260 NORTH ELM ST. • WESTFIELD, MA 01085 • [phone] • FAX [phone]
IN CANADA: 7555 TRANMERE DRIVE • MISSISSAUGA, ONT. L5S 1L4 • [phone] • FAX [phone]
www.hydrothermkn.com
CAUTION: Do not use automotive anti-freeze in the boiler waterways. If the use of antifreeze is necessary an
anti-freeze specifically formulated for hydronic heating systems must be used or damage to the boiler may
occur voiding the warranty!
INSTALLER, THESE INSTRUCTIONS TO BE AFFIXED ADJACENT TO THE BOILER / WATER HEATER.
CONSUMER, RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE PURPOSES.
WARNING: If the information in this manual is not followed exactly, a fire or explosion
may result causing property damage, personal injury or loss of life.
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of
this or any other appliance.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch. Do not use any phone in your building.
• Immediately call your gas supplier from a neighbor’s phone. Follow the gas
supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency or
the gas supplier.
DESIGNED AND TESTED ACCORDING TO A.S.M.E. BOILER AND PRESSURE VESSEL
CODE, SECTION IV FOR A MAXIMUM ALLOWABLE WORKING PRESSURE OF 100 PSI,
700 kPa, WATER.
MEA #444-05-E MASS Plumbers #G1-06-04-28
Advanced Thermal Hydronics
KN SERIES GAS BOILER
WITH CONTROL
INSTALLATION & OPERATING
INSTRUCTIONS

Page 2 KN INSTALLATION AND OPERATION INSTRUCTIONS
AVERTISSMENT. Assurez-vous de bien suivre les instructions données dans cette
notice pour réduire au minimum le risque d’incendie ou d’explosion ou pour éviter
tout dommoge matériel, toute blessure ou la mort
Ne pas entreposer ni utiliser d’essence ou ni d’autres vapeurs ou liquides inflammables
à proximité de cet appareil ou de tout autre appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:
• Ne pas tenter d’allumer d’appareil.
• Ne touchez à aucun interrupteur; ne pas vous servir des téléphones se trouvant dans
le bâtiment.
• Appelez immédiatement votre fournisseur de gas depuis un voisin. Suivez les
intructions du fournisseur.
• Si vous ne purvez rejoindre le fournisseur, appelez le service des incendies.
L’installation et l’entretien doivent être assurés par un installateur ou un service
d’entretien qualifié ou par le fournisseur de gaz.
CONTENTS
Before Your Start ................................................page 2
Ratings & Capacities ..........................................page 3
Location..............................................................page 3
Combustion Air & Ventilation ..............................page 3
Venting Guidelines..............................................page 5
Common Vent Systems ...................................page 13
General Piping Requirements ..........................page 14
Heating System Piping .....................................page 14
Domestic Water Supply Piping .........................page 17
Condensate Piping ...........................................page 18
Gas Supply Piping............................................page 19
Electrical Wiring................................................page 20
Boiler Operation................................................page 20
Operating Instructions ......................................page 21
Sequence of Operation.....................................page 23
Ignition Troubleshooting....................................page 24
Checking & Adjustment ....................................page 26
Diagnostics.......................................................page 27
Maintenance.....................................................page 28
Troubleshooting ................................................page 29
Repair Parts......................................................page 30
Wiring ...............................................................page 33
Warranty ...........................................................page 36
BEFORE YOU START
This manual covers the application, installation,
operation and maintenance of a KN series boiler.
To obtain the safe, dependable, efficient operation and
long life for which this boiler was designed, these
instructions must be read, understood and followed.
The KN boiler series has been design certified by CSA
for use with natural gas under the latest revision of
ANSI-Z21.13/CSA 4.9, Gas-Fired Hot Water Boilers and
CAN1-3.1, Industrial and Commercial Gas Fired
Packaged Boilers. Each unit has been constructed and
hydrostatically tested for a maximum working pressure
of 100 psi, 700 kPa, in accordance with Section IV of the
A.S.M.E. Boiler and Pressure Vessel Code.
All aspects of the boiler installation must conform to the
requirements of the authority having jurisdiction, or, in
the absence of such requirements, to the National Fuel
Gas Code, ANSI Z223.1/NFPA 54-latest revision. Where
required by the authority having jurisdiction, the
installation must conform to the Standard for Controls
and Safety Devices for Automatically Fired Boilers,
ANSI/ASME CSD-1.
If installed in the Commonwealth of Massachusetts, you
MUST FOLLOW the additional instructions contained in
HydroTherm’s instruction sheet MACODE-3. Please
refer to the back of this manual for required regulations.
In Canada, the installation must be in accordance with
the requirements of CSA B149.1 or .2, Installation Code
for Gas Burning Appliances and Equipment.
The owner should maintain a record of all service work
performed with the date and a description of the work
done. Include the name of the service organization for
future reference.
Direct all questions to your HydroTherm distributor or
contact the HydroTherm Customer Service Department
at: 260 North Elm Street, Westfield, MA 01085. Always
include the model and serial numbers from the rating
plate of the boiler in question.

Page 3
KN INSTALLATION AND OPERATION INSTRUCTIONS
RATINGS & CAPACITIES
Before installing the KN boiler check the rating plate to
ensure that the unit has been sized properly for the job.
Also ensure that the unit has been set up for the type
of gas available at the installation site. Other important
considerations are the availability of an adequate
electrical supply, fresh air for combustion and a suitable
vent system.
BOILER LOCATION
1. This boiler is suitable for indoor installations only.
Locate the boiler in an area that provides good
access to the unit. Servicing may require the
removal of jacket panels. Allow the minimum
clearances between adjacent construction and the
boiler as listed in Table 1.
NOTE: Service clearances are not mandatory, but
are recommended to ensure ease of service should
it be required.
Table 1 - Clearances
Clearance to Service
Combustibles Clearance
in mm in mm
Top 6153 24 610
Back 6153 24 610
Left Side 6153 6152
Right Side 6153 6152
Front 6153 36 914
Flue 6153
2. An optimum site will be level, central to the piping
system, close to a chimney or outside wall and have
adequate fresh air for combustion. Ensure that the
unit is level from front to back and from side to side.
Use metal shims if leveling is required.Electrical and
electronic components must be protected from
exposure to water during operation and maintenance.
DO NOT install this boiler in a location that would
subject any of the gas ignition and other electronic
components to direct contact with water or excessive
moisture during operation or servicing.
3. Ensure that the floor is structurally sound and will
support the weight of the boiler.
NOTE: The KN may be installed directly on
combustible flooring, but never on carpeting.
4. Locate the boiler in an area that will prevent water
damage to adjacent construction should a leak
occur or during routine maintenance.
5. DO NOT place this boiler in a location that would
restrict the introduction of combustion air into the
unit or subject it to a negative pressure unless the
combustion air is piped from the outside, see the
COMBUSTION AIR & VENTILATION section.
6. NEVER place this boiler in a location that would
subject it to temperatures at or near freezing.
WARNING: Never store combustible materials,
gasoline or any product containing flammable
vapors or liquids in the vicinity of the boiler.
Failure to comply with this warning can result
in an explosion or fire causing extensive
property damage, severe personal injury or
death!
COMBUSTION AIR & VENTILATION
WARNING: This boiler must be supplied with
combustion air in accordance with Section 5.3,
Air for Combustion & Ventilation, of the latest
revision of the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 and all applicable local building
codes. Canadian installations must comply with
CSA B149.1 or .2 Installation Code for Gas
Burning Appliances and Equipment, or
applicable provisions of the local building codes.
Failure to provide adequate combustion air for
this boiler/water heater can result in excessive
levels of carbon monoxide which can result in
severe personal injury or death!
To operate properly and safely this boiler requires a
continuous supply of air for combustion. NEVER store
objects on or around the boiler!
CAUTION: Combustion air contaminated with fluoro-
carbons or other halogenated compounds such as
cleaning solvents and refrigerants will result in the
formation of acids in the combustion chamber.
These acids will cause premature failure of the
boiler voiding the warranty!
CAUTION: If the boiler is operated while the building
is under construction it must be protected from
wood, concrete, sheet rock and other types of
dust. Failure to properly protect the unit from
construction dust will damage the unit voiding the
warranty!

Page 4 KN INSTALLATION AND OPERATION INSTRUCTIONS
Buildings will require the installation of a fresh air duct
or other means of providing make-up air if the intake
air option isn't used. Any building utilizing other gas
burning appliances, a fireplace, wood stove or any type
of exhaust fan must be checked for adequate
combustion air when all of these devices are in
operation at one time. Sizing of an outside air duct must
be done to meet the requirements of all such devices.
WARNING: Never operate the KN in an environ-
ment subjected to a negative pressure unless it
is Direct Vented. Failure to comply with this
warning can result in excessive levels of carbon
monoxide causing severe personal injury or
death!
All Air From Inside The Building
If the boiler is to be located in a confined space the
minimum clearances listed in Table 1 must be
maintained between it and any combustible construction.
When installed in a confined space without the intake
air option two permanent openings communicating with
an additional room(s) are required. The combined
volume of these spaces must have sufficient volume to
meet the criteria for an unconfined space. The total air
requirements of all gas utilization equipment, fireplaces,
wood stoves or any type of exhaust fan must be
considered when making this determination. Each
opening must have a minimum free area of 1 in2/1000
Btu/hr, 2200 mm2/kW based on the total input rating of
ALL gas utilization equipment in the confined area. Each
opening must be no less than 100 in2, 64,516 mm2in
size. The upper opening must be within 12 in, 300 mm
of, but not less than 3 in, 80 mm from, the top of the
enclosure. The bottom opening must be within 12 in,
300 mm of, but not less than 3 in, 80 mm from, the
bottom of the enclosure.
All Air From Outside The Building
When installed in a confined space without the intake
air option two permanent openings communicating
directly with, or by ducts to, the outdoors or spaces that
freely communicate with the outdoors must be present.
The upper opening must be within 12 in, 300 mm of,
but not less than 3 in, 80 mm from, the top of the
enclosure. The bottom opening must be within 12 in,
300 mm of, but not less than 3 in, 80 mm from, the
bottom of the enclosure.
Where directly communicating with the outdoors or
communicating with the outdoors through vertical ducts,
each opening shall have a minimum free area of 1in2/
4000 Btu/hr, 550 mm2/kW of the total input rating of all
of the equipment in the enclosure.
Where communicating with the outdoors through hori-
zontal ducts, each opening shall have a minimum free
area of 1 in2/2000 Btu/hr, 1100 mm2/kW of the total
input rating of all of the equipment in the enclosure.
When ducts are used, they must have the same cross-
sectional area as the free area of the opening to which
they connect.
Table 2 - Make-up Air Duct Sizing
Required Cross Sectional Duct Area
Input 1/4 in, 6.4 mm Metal Wooden
(MBH) Wire Screen Louvers Louvers
in2cm2in2cm2in2cm2
600 150 967 200 1292 600 3869
1000 250 1612 334 2154 1000 6448
2000 500 3224 668 4308 2000 12,896
When calculating the free area necessary to meet the
make-up air requirements of the enclosure,
consideration must be given to the blockage effects of
louvers, grills and screens.
Screens must have a minimum mesh size of 1/4 in,
6.4 mm. If the free area through a louver or grill is not
known ducts should be sized per Table 2 above.
Direct Intake Air Option - General
This configuration provides combustion air directly to the
boiler’s air intake using a dedicated pipe when using the
direct vent option. Combustion air can be drawn in
horizontally through an outside wall or vertically through
the roof, see Figures 1, 2, 3 & 4. It must be sized per
Table 3.
Single wall galvanized smoke pipe, single wall aluminum
pipe, flexible aluminum pipe, PVC or CPVC pipe can be
used for the intake air pipe.
Table 3 - Intake Air Pipe Sizing
Model Pipe Diameter
Size in2mm2
600 5127
1000 6152
2000 9229
NOTE: All joints in metal intake air systems must be
secured using corrosion resistant fasteners and
sealed using a suitable Silicone caulk. If PVC or
CPVC is used, the joints must be cleaned with a
suitable solvent and connected using a solvent
based PVC cement. The intake air system MUST be
supported by the building structure not the boiler.

Page 5
KN INSTALLATION AND OPERATION INSTRUCTIONS
Direct Intake Air Option - Vertical
The maximum equivalent length for the vertical intake
air pipe is 80 ft, 19.7 m. Each 90° mitered elbow and
the intake air cap are equal to 10 ft, 3.3 m of straight
pipe. If 90° long sweep elbows are installed use the
manufacturers recommended equivalent length.
A listed, nonrestrictive intake air cap must be used. The
intake air cap must terminate as shown in Figure 3. The
penetration point in the roof must be properly flashed
and sealed. Approved caps are listed in Table 4.
Direct Intake Air Option - Horizontal
The maximum equivalent length for the horizontal intake
air pipe is 80 ft, 19.7 m. Each 90° mitered elbow and
the intake air terminal are equal to 10 ft, 3.3 m of
straight pipe. If 90° long sweep elbows are installed use
the manufacturers recommended equivalent length.
Horizontal runs that exceed 5 ft, 1.5 m must be
supported at 3 ft, 0.98 m intervals with overhead
hangers. The intake air terminal must terminate as
shown in Figures 1, 2 or 4. Approved terminals are listed
in Table 5.
Table 4 -Vertical Intake &Vent System Components
Company Description Part Number Dia., in
Flex-L 5
Flex-L 6
Flex-L 9
Heat Fab Rain Cap 5500CI 5
Heat Fab Rain Cap 5600CI 6
Heat Fab Rain Cap 51000CI 9
Pro Tech Rain Cap FSRC5 5
Pro Tech Rain Cap FSRC6 6
Pro Tech Rain Cap FSRC10 9
Z Flex 5
Z Flex 6
Z Flex 9
Table 5 - Horizontal Intake & Vent System
Components
Company Description Part Number Dia., in
Flex-L Vent Adapter 5
Flex-L Vent Adapter 6
Flex-L Vent Adapter 9
Termination T
Termination T
Termination T
Termination EL
Termination EL
Termination EL
Heat Fab Vent Adapter 9501KN10 5
Heat Fab Vent Adapter 9601KN10 6
Heat Fab Vent Adapter 91001KN10 9
Termination T 9590TEE 5
Termination T 9690TEE 6
Termination T 90990TEE 9
Termination EL 7514TERM 5
Termination EL 9614TERM 6
Termination EL 90914TERM 9
Pro Tech Vent Adapter 5
Pro Tech Vent Adapter FSA-HFAG 6
Pro Tech Vent Adapter 9
Termination T 300313 5
Termination T 300314 6
Termination T 9
Termination EL 5
Termination EL 6
Termination EL 9
Z Flex Vent Adapter 5
Vent Adapter 6
Vent Adapter 9
Termination T 02SVSTTX05 5
Termination T 6
Termination T 9
Termination EL 5
Termination EL 6
Termination EL 9
GENERAL VENTING GUIDELINES
WARNING: The vent installation must be in
accordance with Part 7, Venting of Equipment,
of the National Fuel Gas Code, ANSI Z223.1/NFPA
54-latest revision or applicable provisions of
the local building codes. Canadian installations
must comply with CSA B149.1 or .2 Installation
Code. Improper venting can result in excessive
levels of carbon monoxide which can result in
severe personal injury or death!
All vent systems must be fully supported by the building
structure and not by the boiler. Appropriate thimbles and
fire-stops must be used where required.
WARNING: Common positive pressure vent
systems are not to be used! Improper installation
can result in excessive levels of carbon
monoxide which can cause severe personal
injury or death!
NOTE: A single acting barometric damper must be
installed in the vent connector if a vertical vent
system produces a negative draft in excess of 0.2 in,
5.08 mm W.C at the flue outlet.
NOTE: One of the vent system adapters listed in
Table 5 must be attached to the flue outlet of the
boiler before the vent system is connected.

Page 6 KN INSTALLATION AND OPERATION INSTRUCTIONS
Heat-Fab, Inc.
38 Hayward Street
Greenfield, MA 01301, [phone].
Z-Flex U.S., Inc.
20 Commerce Park
North, Bedford, NH 03110-6911, [phone].
Protech Systems Inc.
26 Gansevoort Street
Albany, NY 12202 [phone]
The maximum equivalent length for the horizontal vent
pipe is 80 ft, 19.7 m. Each 90° elbow and the vent
terminal are equal to 10 ft, 3.3 m of straight pipe. To
maximize the performance of single wall sheet metal
vent systems locate 90° elbows as far from the boiler
as possible and from one another. For best results,
horizontal vent systems should be as short and straight
as possible.
The vent system must be both gas and water tight.
All seams and joints in metal pipes must be joined and
sealed in accordance with the vent system manufacturer’s
instructions.
When horizontal vent runs exceed 5 ft, 1.5m they must
be supported at 3 ft, 0.98 m intervals with overhead
hangers.The vent system must be pitched down, toward
the vent terminal, 1/4 in/ft, 21mm/m. If any part of a
single wall metal vent system passes through an
unheated space it must be insulated with insulation
rated for 400°F, 212°C.
Horizontal vent systems shall terminate at least 4 ft,
1.3 m below, 4 ft, 1.3 m horizontally from or 1 ft,
0.23 m above any door, window or gravity air inlet into
any building. It must not terminate less than 4 ft, 1.3 m
horizontally from, and in no case above or below, unless
a 4 ft, 1.3 m horizontal distance is maintained, from
electric meters, gas meters, regulators and relief
equipment and not less than 7 ft, 2.3 m above adjacent
public walkway. The bottom of the vent terminal(s) shall
be located at least 5 ft, 1.5 m above the air intake
terminal(s) unless there is a 5 ft, 1.5 m distance between
them.
Avoid terminal locations likely to be affected by winds,
snowdrifts, people and pets. Protect building materials
and vegetation from degradation caused by the flue
gases.
VENT SYSTEM OPTIONS
The KN may be vented the following ways:
1) Direct Vent - Positive Pressure, Category IV uses
a vent system certified to UL 1738 for installations
in the United States, ULS636 for installations in
Canada. Combustion air is piped from the outdoors
to the blower inlet.
2) Side Wall Vent - Positive Pressure, Category IV
uses a stainless steel vent system certified to UL
1738 for installations in the United States, ULS636
for installations in Canada. Combustion air is
obtained from the space in which the unit is
installed.
3) Vertical Vent - Positive Pressure, Category IV uses
a stainless steel vent system certified to UL 1738
for installations in the United States, ULS636 for
installations in Canada. Combustion air is obtained
from the space in which the unit is installed.
4) Vertical Vent - Negative Pressure, Category II uses
an approved metal chimney system. Combustion air
is obtained from the space in which the unit is
installed.
DIRECT VENT
POSITIVE PRESSURE, CATEGORY IV
In this configuration the boiler blower is used to push
the flue products to the outdoors while drawing
combustion air from the outdoors. The INTAKE AIR
OPTION instructions under the COMBUSTION AIR &
VENTILATION SECTION must be followed! The vent
system must be sized per Table 6.
Table 6 - Direct Vent Pipe Size, Positive Pressure
Model Pipe Diameter
Size in2mm2
600 5 127
1000 6152
2000 9229
Horizontal Direct Vent Systems - Figures 1 & 2
The vent materials used in positive pressure vent systems
must be certified to UL 1738 for installations in the United
States, ULC S636 for installations in Canada. The vent
terminals listed in Table 5 must also be used. Below is a
list of some of the manufactures that have systems that
meet these requirements. Others manufacturers that
have UL certified systems may be used.

Page 7
KN INSTALLATION AND OPERATION INSTRUCTIONS
When running horizontal combustion air and venting for
single or multiple units, exhaust and combustion air
terminals must be installed on the same plane (outside
wall) in order to prevent pressure differences due to
prevailing winds.In cold climates, double-wall or insulated
inlet pipe recommended to prevent condensation.
Vertical Direct Vent Systems - see Figure 3
The vent materials used in positive pressure vent
systems must be certified to UL 1738 for installations in
the United States, ULC S636 for installations in Canada.
The vent terminals listed in Table 4 must also be used.
Below is a list of some of the manufactures that have
systems that meet these requirements. Others manu-
facturers that have UL certified systems may be used.
Heat-Fab, Inc.
38 Hayward Street
Greenfield, MA 01301, [phone].
Z-Flex U.S., Inc.
20 Commerce Park
North, Bedford, NH 03110-6911, [phone].
Protech Systems Inc.
26 Gansevoort Street
Albany, NY 12202 [phone]
The maximum equivalent length for the vertical vent pipe
is 80 ft, 19.7 m. Each 90° elbow and the intake air cap
are equal to 10 ft, 3.3 m of straight pipe. If any part of
a single wall metal vent system passes through an
unheated space it must be insulated with insulation
rated for 400°F, 204°C. Structural penetrations must be
made using approved fire-stops.
The top of a vertical vent system must extend at least
51/2ft, 1.8 m above the roof surface that it passes
through, 4 ft, 1.3 m above the intake air cap, see Figure
3. In addition the vent system must conform to the
dimensions shown in Figure 3. The penetration point in
the roof must be properly flashed and sealed.
The vent system must be gas tight. All seams and joints
in metal pipes must be joined and sealed in accordance
with the vent system manufacturer's instructions.
Combination Direct Vent Systems - see Figure 4
The boiler can be vented vertically with the intake air
piped horizontally through an outside wall. Follow the
instructions in the INTAKE AIR OPTION - HORIZONTAL
GUIDELINES on page 4. Also follow the general
instructions in the COMBUSTION AIR & VENTILATION
and GENERAL VENTING GUIDELINES sections.
KN-6 Multiple Boiler Venting Category II Venting (Negative)
5" AIR
INLET
"A"
"B"
"C"
DOUBLE ACTING
BARAMETRIC DAMPER
THERMAL SPILL
SWITCH
BOILER #1
(ALWAYS LEAD)
BOILER #2
BOILER #3
(IF REQUIRED)
BOILER #4
(IF REQUIRED)
5" FLUE
OUTLET
BOILER #5
(IF REQUIRED)
"D"
ALL CONNECTIONS
TO BE "T-WYE"
Table 1 - Common Vent Sizes
Table 2 - Vent Lengths

Page 8 KN INSTALLATION AND OPERATION INSTRUCTIONS
KN-20 Multiple Boiler Venting Category II Venting (Negative)
KN-10 Multiple Boiler Venting Category II Venting (Negative)
"A"
"B"
"C"
DOUBLE ACTING
BARAMETRIC DAMPER
THERMAL SPILL
SWITCH
BOILER #1
(ALWAYS LEAD)
BOILER #2BOILER #3
(IF REQUIRED)
BOILER #4
(IF REQUIRED)
9" FLUE
OUTLET
"D"
ALL CONNECTIONS
TO BE "T-WYE"
Table 1 - Common Vent Sizes
Table 2 - Vent Lengths
9" AIR
INLET
6" AIR
INLET
"A"
"B"
"C"
DOUBLE ACTING
BARAMETRIC DAMPER
THERMAL SPILL
SWITCH
BOILER #1
(ALWAYS LEAD)
BOILER #2
BOILER #3
(IF REQUIRED)
BOILER #4
(IF REQUIRED)
6" FLUE
OUTLET
BOILER #5
(IF REQUIRED)
"D"
ALL CONNECTIONS
TO BE "T-WYE"
Table 1 - Common Vent Sizes
Table 2 - Vent Lengths

Page 9
KN INSTALLATION AND OPERATION INSTRUCTIONS
Figure 1 - Horizontal Air Intake and Venting for a Single Direct Vent System
Figure 2 - Horizontal Air Intake and Venting for Multiple Direct Vent Systems

Page 10 KN INSTALLATION AND OPERATION INSTRUCTIONS
Figure 3 - Vertical Air Intake and Venting for Direct Vent System
Figure 4 - Combination Direct Vent Systems

Page 11
KN INSTALLATION AND OPERATION INSTRUCTIONS
SIDE WALL VENT
POSITIVE PRESSURE, CATEGORY IV
In this configuration the boiler blower is used to push the
flue products horizontally to the outdoors, see Figure 5.
The air for combustion is taken from the space in which
the unit is installed. The applicable instructions under
the COMBUSTION AIR & VENTILATION SECTION
must be followed! The vent guidelines under the
HORIZONTAL DIRECT VENT SYSTEMS section must
also be followed.
Figure 5 - Side Wall Venting
VERTICAL VENT
POSITIVE PRESSURE - CATEGORY IV
In this configuration the boiler blower is used to push
the flue products vertically to the outdoors, see Figure
6. The air for combustion is taken from the space in
which the unit is installed. The applicable instructions
under the COMBUSTION AIR & VENTILATION
SECTION must be followed! The vent guidelines under
the VERTICAL DIRECT VENT SYSTEMS section must
also be followed.
Figure 6 - Vertical Positive Pressure Venting

Page 12 KN INSTALLATION AND OPERATION INSTRUCTIONS
VERTICAL VENT
NEGATIVE PRESSURE - CATEGORY II
The KN is listed as a Category II appliance when vented
vertically into a listed metal chimney system, Figure 7.
The chimney system must provide a negative pressure
of 0.02 to 0.2 in, 0.51 to 5.08 mm W.C. at the boiler
flue collar with the unit running.
NOTE: When using a listed metal chimney system
the chimney system manufacturer’s instructions
must be followed.
Multiple KN’s can be vented into a single vertical
chimney system. Refer to HydroTherm KN-10 Venting
page 7. Consult factory for multiple KN-6 and KN-20
venting applications.
WARNING: Multiple boiler vent systems must be
designed and verified by a qualified professional
and stack manufacturer. The vent system must
prevent backflow of exhaust gas through idle
boilers.
When more than one appliance is connected to the
same chimney system the system must be large enough
to safely vent the combined output of all of the
appliances.
Table 7 lists the equivalent breeching and chimney
sizes required for a single boiler installation.
WARNING: If an appliance using any type of
a mechanical draft system operating under
positive pressure is connected to a chimney
flue, never connect any other appliances to this
flue. Doing so can result in excessive levels
of carbon monoxide which can cause severe
personal injury or death!
Table 7 - Equivalent Breeching & Chimney Size,
Negative Pressure - Single Boiler
Model Breech & Flue Diameter
Size in2mm2
600 8 204
1000 12 305
2000 18 457
NOTE: These sizes are based on a 20 ft, 6.1m
chimney height.
Vent Connections
Locate the boiler as close to the chimney system as
possible. Use the shortest, straightest vent connector
possible for the installation. If horizontal runs exceed
5 ft, 1.5 m they must be supported at 3 ft, 0.9 m
intervals with overhead hangers. Use the appropriate
vent connector of the same diameter as the flue collar
to connect the boiler to a listed metal chimney system.
Figure 7 -VerticalVenting with a Metal Chimney System
Follow the chimney system manufacturer’s instructions
for proper assembly.
The vent system should be sloped up toward the
chimney at a minimum rate of 1/4 in/ft, 2 cm/m.
WARNING: Never install a vent pipe of a
diameter different than that specified in Table 7.
Failure to comply with this warning can result in
excessive levels of carbon monoxide which can
cause severe personal injury or death.
Always provide a minimum clearance of 6 in, 152 mm
between single wall vent pipe and any combustible
materials.
WARNING: Failure to maintain minimum
clearances between vent connectors and any
combustible material can result in a fire causing
extensive property damage, severe personal
injury or death!

Page 13
KN INSTALLATION AND OPERATION INSTRUCTIONS
COMMON VENT SYSTEMS
If an existing boiler is removed from a common venting
system, the common venting system may then be too
large for the proper venting of the remaining appliances
connected to it. At the time of removal of an existing
boiler, the following steps shall be followed with each
appliance remaining connected to the common venting
system placed in operation, while the other appliances
remaining connected to the common venting system are
not in operation.
Au moment du retrait d'une chaudière existante, les
mesures suivantes doivent être prises pour chaque
appareil toujours raccordé au système d'évacuation
commun et qui fonctionne alors que d'autres appareils
toujours raccordés au système d'évacuation ne fonction-
nent pas: système d'évacuation
a) Seal any unused openings in the common venting
system.
Sceller toutes les ouvertures non utilisées du sys-
tème d'évacuation.
b) Visually inspect the venting system for proper size
and horizontal pitch and determine there is no
blockage or restriction, leakage, corrosion and other
deficiencies which could cause an unsafe condition.
Inspecter de façon visuelle le système d'évacu-ation
pour déterminer la grosser et l'inclinaison
horizontale qui conviennent et s'assurer que le
système est exempt d'obstruction, d'étranglement
de fruite, de corrosion et autres défaillances qui
pourraient présenter des risques.
c) Insofar as is practical, close all building doors and
windows and all doors between the space in which
the appliances remaining connected to the common
venting system are located and other spaces of the
building. Turn on clothes dryers and any appliance
not connected to the common venting system.Turn
on any exhaust fans, such as range hoods and
bathroom exhaust, so they will operate at maximum
speed. Do not operate a summer exhaust fan for a
boiler installation. Close fireplace dampers.
Dans la mesure du possible, fermer toutes les portes
et les fenêtres du bâtiment et toutes les portes entre
l'espace où les appareils toujours raccordés du
système d'évacuation sont installés et les autres
espaces du bâtiment. Mettre en marche les
sécheuses, tous les appareils non raccordés au
système d'évacuation commun et tous les
ventilateurs d'extraction comme les hottes de
cuisinère et les ventilateurs des salles de bain.
S'assurer que ces ventilateurs fonctionnent à la
vitesse maximale. Ne pas faire fonctionner les
ventilateurs d'été. Fermer les registres des
cheminées.
d) Place in operation the appliance being inspected.
Follow the lighting instructions. Adjust thermostat so
appliance will operate continuously.
Mettre l'appareil inspecté en marche. Suivre les
instructions d'allumage. Régler le thermostat de
façon que l'appareil fonctionne de façon continue.
e) After it has been determined that each appliance
remaining connected to the common venting system
properly vents when tested as outlined above, return
doors, windows, exhaust fans, fireplace dampers
and any other gas-burning appliance to their
previous condition of use.
Une fois qu'il a été d éterminé, selon la métode
indiquée ci-dessus, que chaque appareil raccordé
au système d'évacuation est mis à l'air libre de façor
adéquate. Remettre les portes et les fenêtres, les
ventilateurs, les registres de cheminées et les
appareils au gaz à leur position originale.
f) Any improper operation of the common venting
system should be corrected so the installation
conforms with the National Fuel Gas Code, ANSI
Z223.1/NFPA 54. When resizing any portion of the
common venting system, the common venting
system should be resized to approach the minimum
size as determined using the appropriate tables in
Appendix F in the National Fuel Gas Code, ANSI
Z223.1/ NFPA 54 and or CSA B149 Installation
Codes.
Tout mauvais fonctionnement du systéme d'évacu-
tion commun devrait étré corrigé de façor que l'instal-
lation soit conforme au National Fuel Gas Code,
ANSI Z223.1/NFPA 54 et (ou) aux codes d'installation
CSA-B149. Si la grosseur d'une section du système
d' évacuation doit étré modifiée, le système devrait
étré modifié pour respecter les valeurs minimales des
tableaux pertinents de l'appendice F du National Fuel
Gas Code, ANSI Z223.1/NFPA 54 et (ou) des codes
d'installation CSA-B149.

Page 14 KN INSTALLATION AND OPERATION INSTRUCTIONS
Figure 8 - Relief Valve Piping
HEATING SYSTEM PIPING
General Piping Requirements
All heating system piping must be installed by a qualified
technician in accordance with the latest revision of the
ANSI/ASME Boiler and Pressure Vessel Code, Section
IV.
Where required, the piping must comply with ANSI/
ASME CSD-1, Standard for Controls and Safety Devices
for Automatically Fired Boilers.
All applicable local codes and ordinances must also be
followed. A minimum clearance of 1in, 25 mm must be
maintained between heating system pipes and all
combustible construction. All heating system piping must
be supported by suitable hangers not the boiler. The
thermal expansion of the system must be considered
when supporting the system. A minimum system
pressure of 12 psig, 84 kPa must be maintained at the
highest point in the system piping. A minimum system
pressure of 25 psig, 172 kPa fill pressure is required
on glycol mixtures within a closed loop.
GENERAL PIPING REQUIREMENTS
CAUTION: Improper piping of this boiler will void the
manufacturer’s warranty and can cause boiler failure
resulting in flooding and extensive property damage!
NOTE: Shut off valves and unions should be
installed at the inlet and outlet connections of the
boiler to provide for isolation of the unit should
servicing be necessary.
Relief Valve
Pipe the discharge of the pressure relief valve as shown
in Figure 8. Mount on rear section or vertically on supply
nipple.
WARNING: Never install any type of valve
between the boiler and the relief valve or an
explosion causing extensive property damage,
severe personal injury or death may occur!
Flow Switch
The flow switch (optional) is wired to prevent the boiler
from firing unless there's adequate water flow through
the unit.
NOTE: If using the optional flow switch, failure to
maintain the minimum flow rates listed below at the
boiler outlet will prevent the flow switch from closing.
If a minimum flow rate cannot be maintained at the
boiler outlet the flow switch will have to be relocated
in the system.
Water
Flow Rates ΔT Across
(GPM) Heat Exchanger
Min. Max. Min. Max.
KN-6 10 100 20°F 100°F
KN-10 15 150 20°F 100°F
KN-20 30 300 20°F 100°F
Increase flow rates approximately 30% for glycol
mixtures.

Page 15
KN INSTALLATION AND OPERATION INSTRUCTIONS
Cleaning Boiler
Installer must flush and clean out boiler cavity to ensure
unit is cleansed of various impurities.
Boiler Piping Connections
The supply and return connections should be sized to
suit the system, see Table 8.
Table 8 - Supply & Return Pipe Sizing
Model Supply Return
Size Size Size
600 2" NPT 2" NPT
1000 3" NPT 3" NPT
2000 3" NPT 3" NPT
Water Treatment
This boiler was designed to operate in a closed loop
heating system. Water treatment is required when fill or
make-up water contains dissolved solids greater than
200 ppm or if PH level is not within the 6.5-11 range.
Pump Requirements
This boiler requires a continuous minimum water flow
for proper operation. The system pump must be sized
to overcome the head loss of the boiler and the heating
system in order to achieve the required temperature rise.
If the system contains hydronic antifreeze this must be
considered when sizing the pump. The temperature rise
across the boiler must never exceed 100°F, 55.6°C.
Low Water Cutoff
Each KN boiler comes equipped with a factory installed
low water cutoff.
Expansion Tank & Air Separator
An expansion tank or other means to control thermal
expansion must be installed in the heating system. An
expansion tank must be installed close to the boiler on
the suction side of the pump. An air scoop and automatic
air vent must also be installed to eliminate air trapped
in the system.
Reverse Return Piping (RECOMMENDED)
Systems using multiple boilers can also be installed
using a reverse return system, Figure 10.
Primary/Secondary Piping
Although acceptable, the system is not as cost effective
as reverse return piping. Figure 11 shows a typical
primary/secondary piping system. A dedicated pump is
used to maintain a constant water flow through the
boiler. Systems using multiple boilers can be installed
using a primary/secondary manifold system, Figure 12.
Piping For Use With Cooling Units
The boiler, when used in connection with a refrigeration
system, must be installed so the chilled medium is piped
in parallel with the boiler. Appropriate valves must be used
to prevent the chilled water from entering the boiler.
When a boiler is connected to a heating coil that may
be exposed to refrigerated air from an air handling
device, the piping system must be equipped with flow-
control valves or some other automatic means of
preventing gravity circulation of the boiler water during
the cooling cycle.
NOTE: It is essential that following boiler shut off,
the boiler pump continue to operate for
approximately (5) minutes to dissipate the heat away
from the heat exchanger.
Figure 9 - Typical Single Boiler Piping (RECOMMENDED)
(Circulator pump must be sized for minimum water flow rate of boiler, including system pressure drop)
HIOM-64

Page 16 KN INSTALLATION AND OPERATION INSTRUCTIONS
SUPPLY
SYSTEM
RETURN
SYSTEM
COLDWATER
MAKE-UP
Figure 12 - Typical Multiple Boiler Primary/Secondary Piping
Figure 10 - Typical Multiple Boiler Reverse Return Piping (RECOMMENDED)
(Careful consideration as to minimum boiler and system water flow rates must be taken. Please consult our local
manufactures representative for assistance.)
Figure 11 - Typical Single Boiler Primary/Secondary Piping
NOTE: Not all system valves may be shown. Consult local codes for additional system
components which may be necessary.
NOTE: Not all system valves may be shown. Consult local codes for additional system
components which may be necessary.
NOTE: Not all system valves may be shown. Consult local codes for additional system
components which may be necessary.
HIOM-10 REV .2
HIOM-9 REV .2
HIOM-11 REV .3
Motorized
Valve

Page 17
KN INSTALLATION AND OPERATION INSTRUCTIONS
DOMESTIC WATER SUPPLY PIPING
CAUTION: Proper controls must be used to prevent
water supplied for domestic use from exceeding
130°F, 54°C or a scald injury will occur! When higher
water temperatures are required for appliances such
as a dishwasher, a mixing valve or some other
tempering means must be installed. Households
with small children may require water temperatures
less than 120°F, 49°C. Local codes must be complied
with!
General Piping Requirements
The KN boiler can be use in combination with an indirect
tank to provide hot water for domestic use. Piping and
components must be suitable for use with potable water.
The indirect storage tank must be equipped with a
temperature and pressure relief valve that complies with
ANSI Z21.22 or CAN-4.4 and CAN-4.6.
NOTE: The storage tank must be located as close
to the boiler as possible to prevent excessive head
loss which will reduce flow.
Expansion Tank
An expansion tank or other means to control thermal
expansion must be installed in the water heating system
if back flow prevention devices are installed.
Two typical water heating systems are shown in Figures
13 & 14.
Thermostatic MixingValve-Water Above 140°F, 60°C
Water can be stored a temperatures above 140°F,
60°C provided that a thermostatically controlled mixing
valve is used to temper the hot water to an acceptable
temperature before it's supplied for domestic use. The
mixing valve MUST be set to prevent a scald injury from
occurring, see the caution against scalding above.
Storage of water for domestic use above 140°F, 60°C
will provide an increased quantity of tempered water and
help prevent the growth of water born bacteria.
Figure 13 - Typical Single Boiler with Indirect Storage Tank Piping
NOTE: Not all system valves may
be shown. Consult local codes for
additional system components
which may be necessary.

Page 18 KN INSTALLATION AND OPERATION INSTRUCTIONS
Figure 14 - Typical Multiple Boiler with Indirect Storage Tank Piping
CONDENSATE PIPING
The condensate trap provided with the boiler must be
attached to the bottom pan and piped to a suitable floor
drain (consult local code) or condensate pump. If a
condensate neutralization device is installed, it must be
positioned prior to boiler room drain. Fill the condensate
fill trap with water and antifreeze solution prior to start-
up.
NOTE: Not all system valves may
be shown. Consult local codes for
additional system components
which may be necessary.
4
3
HIOM-82
3
4
K
1
KN-6 and KN-10 Condensate Drain
SPARE PARTS LIST
ITEM # MODEL PART No. DESCRIPTION QTY
1KN-6 & 10 10/1/5038 1/4" SILICONE TAPE 1 ROLL
2KN-6 01-1635 LOWER CASTING COVER 1
KN-10 01-1631 1
3KN-6 54-3229 3/4" SILICONE TUBING 2'
KN-10 3'
4 KN-6 & 10 70-1338 CONDENSATE DRAIN 1

Page 19
KN INSTALLATION AND OPERATION INSTRUCTIONS
GAS SUPPLY PIPING
WARNING: Check the boiler rating plate to make
sure that the boiler is for the type of gas that
will be used. If it isn’t, do not connect the boiler
to the gas supply. Failure to comply with this
warning can result in extensive property
damage, severe personal injury or death!
The KN comes from the factory ready to be piped to
the gas supply. If for any reason the boiler is not for the
type of gas available at the installation site, call your
HydroTherm representative to resolve the problem.
Table 9 should be used to ensure that the gas supply
piping is sized properly. If more than one appliance is
supplied by the same supply pipe, the piping must be
sized based on the maximum possible demand. Do not
neglect the pressure drop due to pipe fittings. Table 9
should be used in conjunction with Table 10 to ensure
that the gas supply piping has the capacity to meet the
demand.
Figure 15 depicts the proper way to connect the boiler
to the gas supply piping. The manual shut-off valve
MUST be installed in the supply piping. It should be
installed 5 feet above the floor where required by local
codes. Provide a sediment trap at the bottom of the
vertical section of the gas supply pipe upstream of the
gas controls.
A ground joint union should be installed between the
boiler gas controls and the supply piping. Each of these
items are needed to ensure long life and ease of
servicing. Always use a pipe sealant that is suitable for
use with LP gas.
Table 9 - Gas Pipe Capacity
Pipe length in feet
10 20 30 40 50 60 80 100 150
Maximum gas volume of pipe (ft3/hr)
520 350 285 245 215 195 170 150 120
1050 730 590 500 440 400 350 305 250
1600 1100 890 760 670 610 530 460 380
3050 2100 1650 1450 1270 1150 990 870 710
Nominal
Iron Pipe
Size, (in)
1ʺ
11/4ʺ
11/2ʺ
2ʺ
Maximum pipe capacity in ft3/hr based on 0.60 specific gravity gas
at a pressure of 0.5 psig or less and a 0.3" WC pressure drop.
Note: Multiply the gas volume by 0.62 for propane flow capacity in
ft3/hr.Multiply the propane flow capacity by 2500 Btu/ft3 to determine
the propane Btu/hr capacity for a given pipe size and length.
SECTION "A"
SECTION "B"
SECTION "D"
SECTION "C"
HIOM-81
8
553
-
1078
6 70-133
8
7 01-163
3
8 10-503
8
SPARE PARTS LIST
ITEM PART No. DESCRIPTION QTY.
1 56-3348 HEAT FAB ADAPTER 1
2 56-5739 1
2" ID BARB 90° ELBOW 1
3 54-3229 3
4" SILICONE TUBING 4.5'
4 56-5738 3
4X 3 4X 3 4HOSE TEE 1
5 53-1078 1
2X 2 PIPE NIPPLE 1
6 70-1338 CONDENSATE DRAIN 1
7 01-1633 LOWER CASTING COVER 1
8 10-5038 1
4" SILICONE TAPE 1 ROLL
KN-20 Condennsate Drain

Page 20 KN INSTALLATION AND OPERATION INSTRUCTIONS
Type of pipe fitting
90° Elbow Tee1Gas Valve2Gas Cock2
Equivalent pipe length, (ft)
2.6 5.2 0.6 1.5
3.5 6.9 0.8 1.9
4.0 8.0 0.9 2.3
5.2 10.3 1.2 3.0
Nominal
Iron Pipe
Size, (in)
1ʺ
11/4ʺ
11/2ʺ
2ʺ
Notes: 1. For flow through branch.
2. For flow at full open.
Whenever the gas supply piping is pressure tested
the boiler gas controls must be protected. If the test
pressure is equal to, or less than 1/2 psig, 3.5 kPa
isolate the boiler by closing its' manual shut off valve,
see Figure 15. If the test pressure is greater than, or
equal to 1/2 psig, 3.5 kPa, disconnect the boiler and its
individual shut-off valve.
ELECTRICAL WIRING
Electrical Power Connections
CAUTION: Label all wires prior to disconnection
when servicing controls. Wiring errors can cause
improper and dangerous operation! Verify proper
operation after servicing.
ATTENTION. Au moment de l'entretien des com-
mandes, étiquetez tous les fils avant de les
débrancher. Des erreurs de câblage peuvent
entraîner un fonctionnement inadéquat et
dangereux. S'assurer que l'appareil fonctionne
adéquatement une fois l'entretirn terminé.
The electrical connections to this boiler must be made
in accordance with all applicable local codes and the
latest revision of the National Electrical Code, ANSI /
NFPA-70. Installation should also conform with CSA
C22.1 Canadian Electrical Code Part I if installed in
Canada. Install a separate 120 volt 15 amp circuit for
each KN-6 or KN-10 boiler. Install a separate 208/230
volt 20 amp circuit for each KN-20 boiler. A properly
rated shut-off switch should be located at the boiler. The
boiler must be grounded in accordance with the
authority having jurisdiction, or if none, the latest revision
of the National Electrical Code, ANSI/NFPA-70.
Line voltage field wiring of any controls or other devices
must use copper conductors with a minimum size of #14
awg. Use appropriate wiring materials for units installed
outdoors.
Refer to point of connection diagram in back of this
manual and the wiring diagram supplied with the boiler
for proper wiring connections.
BOILER OPERATION
WARNING: Before proceeding read and fully
understand the instructions contained in this
manual. Do not attempt to operate this boiler if
it has not been installed in accordance with the
guidelines set forth in this manual. Failure to
comply with this warning can result in extensive
property damage, severe personal injury or
death!
Table 10 - Equivalent Pipe Length Chart
Figure 15 - Gas Supply Piping
NOTE: All boilers ship with a Maxitrol gas pressure
regulator.The regulator must be installed in the gas
supply piping.The regulator should be installed at a
distance of at least 10 pipe diameters from the
boilers main gas valve. The regulator should be
adjusted to provide 4" w.c. pressure to the gas
valve.
NOTE: All boilers are calibrated and factory test
fired at 4" w.c. supply gas pressure.
CAUTION: Always use a wrench on the gas valve
body when making gas connections to it. Never
over-tighten the piping entering the gas valve body
or gas valve failure may result!
Safe lighting and other performance criteria were met
with the gas manifold and control assembly provided
on the boiler. All gas connections MUST be leak tested
before putting the boiler into operation.
WARNING: Never use an open flame to test
for gas leaks. Always use an approved leak
detection method. Failure to comply with this
warning can cause extensive property damage,
severe personal injury or death!