ATH HeatNet KN-2 User manual

is manual is intended only for use by a qualied heating installer/technician. Read and follow this manual, all supplements and related
instructional information provided with the boiler. Install, start and service the boiler only in the sequence and methods given in these
instructions. Failure to do so can result in severe personal injury, death or substantial property damage.
Do not use the boiler during construction. Construction dust and particulate, particularly drywall dust, will cause contamination of
the burner, resulting in possible severe personal injury, death or substantial property damage. e boiler can only be operated with a dust-
freeairsupply.Follow the instruction manualprocedurestoductairtotheboilerairintake.Iftheboiler has been contaminatedbyoperation
with contaminated air, follow the instruction manual guidelines to clean, repair or replace the boiler if necessary.
Ax these instructions near to the boiler/water heater. Instruct the building owner to retain the instructions for future use by a qualied
service technician, and to follow all guidelines in the User’s Information Manual.
Cast Iron Condensing
Boilers
Models KN - 2 and KN - 4
HeatNet® Manual
KN-2/4-CM2-0714
42-9452
Control Adjustment and Operation Instructions
for Mestek Firmware Version 2.8
Also read and follow:
KN Boiler Manual
KNVent/Air Manual
KN - 2 only

2
KN USER’S CONTROL MANUAL
The KN boiler — HeatNet® control
Control overview
e KN HeatNet control monitors boiler temperature and limit
circuit inputs, modulating boiler ring rate to meet demand.
e control uses microprocessor electronics, watching time-
average response from the system to anticipate how much heat
thesystemneeds.Coupledwiththe ve-to-oneturndown of the
KN boiler, this results in maximum possible condensing-mode
operation. e KN boiler will provide unmatched seasonal
eciency.
Indoor air reset (IAR)
KN’s unique approach to boiler output regulation is its Indoor
Air Reset function. e control monitors the demand from up
to 8 dierent zones. Watching the demand duration and response
to supply temperature, averaging over time, the HeatNet control
anticipates system needs. It sets boiler maximum ring rate and
adjustssupplywatertemperaturetone-tuneboiler heatoutput.
All that is required to enable IAR is to connect thermostat
circuit wires to the IAR inputs. e HeatNet control can also
be congured for outdoor reset operation, but IAR provides
response based on system behavior rather than just looking at
outdoor temperature.
The HeatNet platform
HeatNet controls are designed to provide an integrated boiler
management system on every boiler. e platform provides
multiple levels of selectivity. HeatNet electronics can be
operated as a simple single-boiler control, while still providing
intelligent regulation of boiler ring rate to match system
demand. With a few key strokes on the key pad, the HeatNet
control can operate as a sophisticated multiple-boiler controller,
using simple RJ45 cable interfacing between units. e control
can even accept external control commands from building
managements systems (Modbus standard, with optional bridge
for BACnet or LonWorks) or 20-milliamp analog input from an
external controller.
e control method used by the HeatNet control is based on
digital communications, which eliminates the need for analog
control signals. Analog signal inputs are supported, but a higher
level of control precision, repeatability and feedback is gained
with digital communications.
e HeatNet control can be versatile, providing for operation
in multiple ways:
• Operation as a stand-alone boiler.
• Operation as a boiler in a boiler network, using the on-board
HeatNetprotocol.
• Operation as a member boiler in a boiler management
system.
• Operation as a member of a remotely-controlled boiler
network (20-milliamp regulation).
• Setpoint can be determined by the HeatNet control or by a
20-milliamp input signal.
• Network boilers can be operated by override commands
for increased versatility.
PID response
e HeatNet control uses proportional-integral-derivative
calculations to determine the response to boiler water
temperature changes. is means it not only looks at how far
away the water temperature is from the setpoint temperature,
but how fast the temperature is changing and how it has
respondedovertime.isensurestheboilerwon’tmakesudden
unnecessary changesinringrate.
Multiple boiler operation
e HeatNet control easily interfaces with other HeatNet
controls. Multiple boiler operation using HeatNet protocol only
requires RJ45 cables daisy-chained from boiler to boiler and a
few key strokes seing up control behavior. e master boiler is
automatically selected by connecting a sensor lead to its
HEADER sensor terminals. e HeatNet control recognizes
the sensor and congures the boiler as the master. Other boilers
only need to have an address assigned.
Among the advanced design features of the HeatNet control is
theMOD-MAX seing. is limits thering rateofall boilersto
a pre-set maximum (50% by default). is means all of the
boilers will be run at a very ecient level until all boilers are on.
Only then can ring rate increase above this seing. Boiler
rotationcanberst-on/rst-o,rst-on/last-o,ortruerotation
(the HeatNet control monitors the total on time of all boilers,
and rotates their usage so the total on time is the same for all).
Firmware Version 2.5 and greater is now compatible with
HeatNet Mixed Boiler Systems. For more information on the
operation of HeatNet Mixed Boiler Systems see the KN6-30
HeatNet Control Manual V3.47, which is available at www.
knseries.com.
External limit monitoring
& annunciation
In addition to controlling the boiler, the HeatNet control
monitors external limits wired into the limit circuit connections.
econtrolshuts downthe boiler ifa limit opens,and thedigital
display shows which limit failed. Monitored limits include high
limit aquastat, ow, ignition control fault, inlet pressure, ue
pressure and other optional or user-selectable limits.”

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KN USER’S CONTROL MANUAL
The KN boiler — HeatNet® control
components
Wiring connections
1. Power wiring, 120 vac
2. Heat demand input
3. DHW demand input
4. Low re terminals
5. High re terminals
6. To boiler outlet water
temperature sensor
7. To optional outdoor
temperature sensor
8. To optional boiler return
water temperature sensor
9. To optional header
temperature sensor
10. To boiler postpurge pump
(factory piped and wired)
11. To boiler circulator
12. Alarm output dry contacts
13. To external high limit and/or
low water cuto if desired
14. To ow switch, when used
15. Used to activate combustion
air damper if desired
16. To combustion air damper proving
switch, required when controlling
combustion air damper
17. Indoor air reset inputs — connect
to up to 8 zone thermostats
18. Optional 20 ma control signal input
19. Remote enable to start when
operating on 20 ma input
20. Optional HeatNet
communications board
21. Boiler wiring socket to blower
and gas valve
22. Boiler wiring socket to pressure
switches and ignition control
23. Boiler wiring socket to
control panel
24. Boiler wiring socket to
control panel
25. Boiler wiring socket to
power switch
26. Boiler wiring socket to transformer
27. Termination DIP switches

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KN USER’S CONTROL MANUAL
1 Method 1: HeatNet modulation – control. . . . . .page 5
• e KN HeatNet control can control up to (16) KN boilers using built-in soware and
hardware.
• Install a RS485 interface on each boiler and connect with RJ45 HeatNet cables
(or shielded wires).
• e header water temperature setpoint can be set by the master boiler or by a 4-20ma
input from an external controller.
• Member boilers can override master boiler control if they receive a contact closure on
the Heat Demand or DHW Demand terminals.
2 Method 2: HeatNet modulation – BMS . . . . . page 14
• is method uses the KN control’s built-in communications capabilities to accept
Modbusprotocolinputs from a buildingmanagementsystem.emasterboiler control
sequences and modulates the boiler network to accomplish the demands from the
building management system.
• Each boiler requires the RS485 interface board and cable, above.
• Boiler setup is essentially the same as for method 1, with the exception that each boiler
must be assigned both a HeatNet network address and an address for the Modbus
interface.
• An additional bus is required to interface with systems using BACnet or LonWorks protocol.
• e master boiler will take control and regulate the boiler network if signal from the
BMS is lost or times out.
3 Method 3: External 4-20ma control . . . . . .page 16
• Up to 5 boilers can be controlled by an external control that provides a 4-20ma input
signal. e external controls must also activate each boiler by closing a contact across
the boiler’s 4-20ma Remote Enable contacts.
• Member boilers can override external boiler control if they receive a contact closure on
the Heat Demand or DHW Demand terminals.
4 Failsafe modes . . . . . . . . . . . . . . . . . . . . . . . . . .page 22
5 Control menus and adjustments . . . . . . . . .page 23
• Operating parameters and control behaviors are set using the KN control’s display/
keypad interface.
• Refer to this section for the menu structure and explanations of the seing options.
6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . .page 35
7 Communication Registers . . . . . . . . . . . . . . .page 40
Contents
HeatNet
Control panel

5
KN USER’S CONTROL MANUAL
Method 1: HeatNet modulation – local control
1
Overview — control setup sequence
Follow the Boiler manual — Install the boilers according to the KN
Boiler manual before aempting to set up the control system.
1. Install all boilers per the Boiler manual.
2. Close the external gas valve on every boiler.
3. Wire all boilers following the guidelines in this section.
4. Aach a header sensor to the master boiler ONLY. e KN-2 control automati-
cally congures the boiler with a header sensor as the master.
5. Set the master boiler control parameters using its display/keypad.
6. Set the master boiler’s termination DIP switches.
7. Set the termination DIP switches on the member boilers.
8. Set the member boilers’ control parameters using their display/keypads.
9. Follow the instructions in the Boiler manual to start up each boiler before proceeding
further.
10. Finish by connecting cables between the communications boards of all of the boilers
and verifying network operation.
Add communications modules
1. Insert aRS485 communicationsmodule ontoeach ofthe boilers’electrical connection
panels, as shown in Figure 1.
Power supply (120 VAC)
1. See Figure 1 and Figure 2.
2. Connect minimum 14awg copper wire to the power connection as shown in Figure 2.
3. Install a fused service switch, mounted and installed in accordance with all
applicable codes.
Figure 1 Electrical connection board (see item 10,
page 3 for location — Also see the wiring
summary illustrations on the next pages)
Figure 2 120VAC power service terminals on electrical
connection board — See Figure 15 for location
of the power terminal strip
Electrical shock hazard — Disconnect all electrical power
sources to the boiler before making any electrical connections.
Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation!
Verify proper operation aer servicing.
Failureto comply with theabovecouldresultin severepersonal
injury, death or substantial property damage.
e 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 to CSA C22.1 Canadian
Electrical Code Part I if installed in Canada. Install a separate
120 volt 15 amp circuit for the boiler. A properly rated shut-
o switch should be located at the boiler. e 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 eld 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.

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KN USER’S CONTROL MANUAL
Method 1: HeatNet modulation – local control (cont.)
1
Figure 3 Wiring the boiler circulator using a circula-
tor relay (required for motors over 1/4 hp)
Figure 4 Wiring the boiler circulator using a relay or
starter (required for motors over 1/4 hp)
Circulator wiring
Postpurge circulator (KN-2 only)
• The circulator shipped installed with the boiler
cannot be used for system circulation. It must be used
as supplied from the factory. It circulates water aer the
boiler stops ring to prevent potential damage from heat
pocketing in the top of the heat exchanger.
• epostpurgecirculatoris factory-piped and pre-wired. Do
not change the usage, the wiring, the location or the piping.
Boiler circulator
• See the Boiler manual for circulator piping.
• Figure 3, Figure 4, and Figure 5 show wiring of the Boiler
circulator (or boiler/system circulator) to the terminal strip
of the KN-2 electrical connection board.
• DO NOT directly connect a circulator with a motor larger
than 1/4 hp. For larger motors, install a circulator relay or
motor contactor . Figure 3 and Figure 4 show the correct
ways to install the boiler circulator using a relay or motor
starter.
(KN-2 only)
Figure 5 Circulator wiring terminal strip (see Figure 1
for location) — Also see the wiring
summary illustrations on the next pages)

7
KN USER’S CONTROL MANUAL
Figure 6 Indoor Air Reset wiring to IAR terminals with
4-wire zone valves and no zone controller
(see Figure 7 for terminal block 6location)
Method 1: HeatNet modulation – local control (cont.)
1
IAR (Indoor Air Reset) wiring, when used
• Heat Demand terminal connections — e end switch leads from the zone valves
must connect to the Heat Demand terminals on the electrical connection board as
shown in Figure 7.
• See Figure 6 for typical wiring to the IAR inputs when using 4-wire zone valves
without a zone controller. For other applications, such as circulator relays or zone
controllers, see Appendix A in the Boiler manual..
Polarity — e connections to the IAR positive terminals (IAR +)
must be to the same location on the zone valve as the thermostat wire, as
shown in Figure A1. e connections to the IAR negative terminals
(IAR –) must be from the zone valve terminal connected to the 24VAC
common line, as shown. Connecting the wires incorrectly can cause the
transformer to be shorted out and damaged. Verify the wiring with a
voltmeter.
Always use a voltmeter to check the leads coming from the end switches
of the zone valves. With the thermostat calling for heat, connect the
voltmeter leads across the wires coming from the end switches. If the
meter shows a voltage reading, the zone valve wires are incorrect.
Change the wiring and retest. DO NOT connect the wires to the boiler
until you have tested as described. Incorrect wiring can damage the
boiler control or other system components.
• If there is only one transformer feeding all of the zone valves in the system, you can
omit the wires to the IAR negative terminals (IAR –) on all but one of the zone
valves. is is because these terminals are jumpered internally on the electrical
connection board. If there is more than one transformer, provide one wire from
each transformer common side to one of the IAR negative terminals (IAR –).
Sensor wiring
• Header sensor is required — A header sensor must be installed in the system
supply piping. Connect the header sensor ONLY to the master boiler. Install
the header sensor in an immersion well. Locate the sensor where it will accurately
sense the system water supply temperature. Connect the sensor leads to the
electrical connection board as shown in Figure 8.
• Outdoor reset application — To operate with outdoor reset, purchase and
install an outdoor sensor. Mount the sensor such that it is shielded from direct
sunlight if possible and not likely to be covered by snow dris or debris. Connect
the outdoor sensor leads to the master boiler’s electrical connection board as
shown in Figure 8. (Member boilers could have their own outdoor sensor if they
will be operated in override mode by closing the Heat Demand terminals.)
• Return water temperature sensor — e return water temperature sensor is
optional, only needed if you want to automatically control the boiler postpurge
pump cycle time. Install the sensor in a well in the boiler return piping. Connect
the sensor leads to the electrical connection board as shown in Figure 8, e
Return water sensor can OPTIONALLY be used as a DHW sensor. e control
would then regulate to this sensor for DHW demands. When used in this way the
sensor must be moved to a position where it will sense the temperature of the
water being supplied to the tank. For more information see the DHW SENSOR
description in Table 8.
• Sensor wiring, return water temperature sensor —Firmware Version 2.5
and greater monitors the temperature dierential (Delta T) across the heat
exchanger. If the Delta T exceeds the seing, the input to the boiler can be
optionallylimited.
DHW wiring
• To operate the boiler for domestic water heating with a storage tank, install and pipe
the tank according to the tank manufacturer’s instructions and the recommended
piping diagrams in this manual. Consult the factory for applications not covered.
• e circulator used for DHW must be operated by a circulator relay or zone
controller that is activated when the tank aquastat calls for heat, as shown in
(Figure7-terminal#2).
• Connect the tank enable terminals across the DHW DEMAND terminals on the
master boiler’s electrical connection board as shown in Figure 7. (Member boilers
could be connected to tank aquastats if they are piped appropriately and intended
to operate in override mode.)

8
KN USER’S CONTROL MANUAL
Figure 7 KN wiring summary — wiring to electrical connection board
Method 1: HeatNet modulation – local control (cont.)
1
Also see Figure 2.
J9 Control Inputs
(Connect remote temperature control 4-20mA input wires here
when remote setpoint
is required. The setpoint temperature
will be set by the 4-20mA signal. The corresonding setpoint
values can be set in the 4-20mA INPUT menu.)
Master boiler: Room thermostats,
end switches or relay contacts
(Connect thermostat, zone valve end switches,
or remote start relay contact here. Test when done
to ensure no stray voltage is present on any of the
wires. See the Boiler manual for procedure.)
Master boiler: Connect override contacts only
(Individual boilers, if piped appropriately, can be
activated for override operation, such as DHW
heating or emergency space heating.)
The boiler is shipped with a
jumper across the HEAT DEMAND
terminals. Remove this jumper
when using a thermostat or other
external control to start the boiler.
Tank
Aquastat
GND
DHW Relay
50VA
120VCom
24VAC
24V
Com
RI
DHW Pump Motor
JI4
15
120VAC
Supplied, mounted and wired by installer
Wire Harness 70-2043
Factory Wiring — Do Not Change

9
KN USER’S CONTROL MANUAL
(KN-2 only)
Note: For multiple boilers with a single combustion air damper
Figure 8 KN wiring summary — wiring to electrical connection board, continued (see Figure 7 for terminal strip locations)
Also see Figure 5.
Method 1: HeatNet modulation – local control (cont.)
1

10
KN USER’S CONTROL MANUAL
External interlocks
1. Wire external limits and ow switch, when used, as shown in Figure 8.
2. If wiring to and from a motorized combustion air damper, follow the guidelines
given in Figure 8. Connect only to the master boiler.
If any of the member boilers is to operate in override mode, and the
system is equipped with a combustion air damper, you must provide
special wiring in order to ensure the damper opens and proves when
the boiler res. is must be done without compromising the wiring
between the master boiler and the damper.
Overrides — Control priorities
3. e KN control can provide override operation for any or all member boilers in
a HeatNet network. is requires the boilers be piped with appropriate isolation
piping and controls.
4. Override is done by closing a contact across the Heat Demand or DHW Demand
terminals of any boiler. ese priority inputs override all network controls or
4-20mA input controls to the boiler.
5. DHW Demand — e DHW Demand closure takes priority for ALL boilers,
including the master and all members. When DHW Demand closes, the boiler
or boilers immediately switch to DHW operation, including seing the water
temperature to the DHW Setpoint.
6. Space heating, Heat Demand — If any member boiler sees closure across its
Heat Demand terminals it will begin operation in space heating mode indepen-
dently of commands from the master boiler or 4-20mA input source.
Do not wire boilers for override operation unless the piping design
provides automatic isolation of the overriding boilers. e master
boiler would be unable to properly control system water temperature
if member boilers were to input heat to the system without control
from the master. DHW operation, in particular, would raise the supply
temperature from overriding boilers to the DHW Setpoint.
Override operation control setup — Boilers must be set up with
operating parameters necessary during their override operation; i.e.,
local setpoint, DHW setpoint, etc.
7. Summary — priority sequence is:
Priority 1 = DHW Demand
Priority 2 = Heat Demand
Priority 3 = HeatNet input
Set termination DIP switches
1. e HeatNet network needs to recognize the beginning and end of the
network. is requires seing the four DIP switches on each boiler’s electrical
connection board.
2. See Figure 9 for location of the switches.
3. See Table 1 for required seings. e table gives seings for HeatNet modulation
— local control and for remote control from a building management system
(Modbus protocol).
4. DO NOT connect the communications cables (or shielded wires) between boilers
until all boilers have had parameters set and then been started up following all
instructions in the KN Boiler manual.
Figure 9 Termination DIP switches (see item 7, Figure 7
for location)
Table 1 Termination DIP switch settings
Boiler HeatNet Modbus
(see note)
Master Switch 1: ON
Switch 2: ON
Switch 3: OFF
Switch 4: OFF
Switch 1: ON
Switch 2: ON
Switch 3: ON
Switch 4: ON
Last member Switch 1: ON
Switch 2: ON
Switch 3: OFF
Switch 4: OFF
Switch 1: ON
Switch 2: ON
Switch 3: OFF
Switch 4: OFF
Other members Switch 1: OFF
Switch 2: OFF
Switch 3: OFF
Switch 4: OFF
Switch 1: OFF
Switch 2: OFF
Switch 3: OFF
Switch 4: OFF
Note: Modbus setup is for applications controlled by a building management system. For
systems using BACnet or LonWorks, a bridge board is used to interface with the KN-2
control. e switch is “on” when in the down position and “o ” when in the up position.
Method 1: HeatNet modulation – local control (cont.)
1

11
KN USER’S CONTROL MANUAL
Method 1: HeatNet modulation – local control (cont.)
1
Figure 9A KN2/KN4 multiple boilers with a single combustion air damper

12
KN USER’S CONTROL MANUAL
Table 2 Control parameters
Parameter Master
boiler
Member
boiler
(see notes)
HEAT BAND Set on master boiler only
LOC SETPOI NT Set HD only1
SOURCE Set HD or DHW only1,2
DHW SETPOINT Set if DHW will
be used
DHW only2
OP LIMIT Set Set
LIMIT BAND Set Set
IA RESET ON if IAR is used,
or set to OFF
Do not set
OA SHUTDOWN Set ON if used
or set to OFF
HDOA only3
OA SETPOINT Set if used HDOA only3
OA RESET Set if used HDOA only3
OA SETPTS Set if used HDOA only3
DELTA ENABLE Set if used Set if used
DELTA TEMP Set if used Set if used
PURGE TIME Set if used Set if used
ALWAYS ON Set if used Set if used
MASTER PUMP Set if used Do not set
NIGHT SETBACK Set on master boiler only
OPTIONS (all) Set Set
AUX FUNCTIONS Set on master boiler only
SYSTEM CLOCK Set Set
LOCAL ADD Automatic Set (beginning at 2)
CONSOLE ADD Automatic Set (beginning at 2)
MODULAR BOILER Set on master boiler only
MODULATION PID Set on master boiler only
FIRING MODE Set on master boiler only
SENSOR # Set HD/HDOA only1,3
TYPE Set HD/HDOA only1,3
CALIBRATE ? On any boiler if required
PASSWORD Set Set
COMMUNICATIONS Set Set
LOAD DEFAULTS On any boiler if required
SYSTEM On any boiler if required
Notes:
1 — HD Only means to set the parameter for a member boiler only if it is wired for
Heat Demand override.
2 — DHW Only means to set the parameter for a member boiler only if it is wired
for DHW Demand override.
3 — HDOA Only means to set these parameters only if the member boiler will be
operated with outdoor reset when put in override mode with closure across its Heat
Demand terminals (requires outdoor sensor connected to boiler).
Set control parameters on keypads
Before turning boilers on to set parameters, disconnect all call for heat
wiring at the electrical connection boards. is will prevent the boiler
for aempting to cycle during the setup process.
1. See “Control menus and adjustments” for a complete list of control parameters
and explanations.
2. Carefully read the parameter explanations in Table 8.
3. When adjusting the limit band, operating limit (OP LIMIT), local setpoint (LOC
SETPOINT) and DHW setpoint, make sure the operating temperature bands do
not overlap or cause potential for nuisance cycling.
4. Indoor air reset — Use this option whenever possible. e indoor air technology
monitors space heating demand to help the boiler operate at the highest possible
eciency throughout the season. To operate with IAR, you must wire to the IAR
input terminals as described on page 18.
5. System clock — Set the system clock on all boilers to ensure the time stamps will
be accurate in the data logs.
6. Turn on the power to each boiler and set the on/o switch to ON as you set its
parameters.
7. Use the boiler’s keypad to enter the parameters as described on page 23.
8. Aer seing a boiler’s parameters, turn the power o to the boiler until you are
ready to start the boiler up following the Boiler manual instructions.
9. Set the master boiler and each member boiler, following the guidelines given in
Table 2.
Start up boilers per KN Boiler manual
1. Turn o power to all boilers.
2. Follow all instructions in the KN Boiler manual to start up each boiler and verify
operation.
Connect network cables
Electrical shock hazard — Turn o power to each boiler before
aempting to connect the network cables.
Before turning boilers on to check network operation, disconnect all
call for heat wiring at the electrical connection boards. is will prevent
the boiler for aempting to cycle during the setup process.
Master boiler cable
1. ConnectanRJ45 cabletothe masterboiler H-LinkOUTblock(item2,Figure 10)
or 3-wire shielded cable to the H-Link terminal strip (item 4, Figure 10). e other
end of this cable will be aached to the rst member boiler in following steps.
Close the external manual gas valve on every boiler before
proceeding.DO NOTopen anygasvalve, or aempttoreany
boiler, until the boilers have been set up and veried following
the instructions in the KN Boiler manual.
Failuretocomplycouldcauseaboilerfailure,leadingtopossible
severe personal injury, death or substantial property damage.
Method 1: HeatNet modulation – local control (cont.)
1

13
KN USER’S CONTROL MANUAL
Figure 10 RS485 communications board
2. Turn on power to the master boiler and set its on/o switch to ON.
3. You should hear at least 2 beeps.
4. e control’s rmware version number will display.
5. Aer the control’s timer nishes, the display will
show STANDBY and SYS SET. is veries that
the master boiler is setup correctly as the master.
e same display will show on member boilers when there is a call for heat from
the master boiler. When there is no call for heat at a member boiler, the display will
show LOC SET instead.
6. If the master is functioning correctly, the yellow LED’s on the H-Link jack ports
will blink. e blinking indicates that the master is trying to communicate with
member boilers.
7. If a FAULT message is displayed, clear the faults until the STANDBY message is
displayed. Refer to troubleshooting suggestions at the end of this manual if you
cannot resolve the issue.
Member boiler cables
1. Begin with the rst member boiler.
2. Plug the other end of the master boiler’s communications cable to the member boiler’s
input port (Figure 10, item 2 for RJ45 cable or item 4 for 3-wire cable).
3. Connect cablesto all of themember boilers by cablingfrom one to the next. Connect
incoming cables to item 1 or 4, Figure 10. Connect outgoing cables to item 2 or 4.
(Note that shielded cable wires will share terminals when using item 4.)
Check the network
1. Turn the power on and the on/o switch to ON for all of the member boilers.
2. Allow time for each boiler to initialize.
3. Aer about 30 seconds, the master boiler should recognize the member boilers.
4. Navigate to the BOILERS menu, then to HEAT
NET BOILERS display. e master control will
show the boilers it recognizes.
5. If the display shows a blank space, such as “123_56789” the control does not
detect the missing boiler (boiler 4). Check the yellow LED on the communication
port of the missing boiler.
6. NORMAL connection — LED should ash steadily, about twice per second.
7. TERMINATION incorrect — LED will ash rapidly and stay on.
8. OPEN connection — LED does not ash at all.
9. If a FAULT message is displayed, clear the faults until the STANDBY message is
displayed. Refer to troubleshooting suggestions at the end of this manual if you
cannot resolve the issue.
Start the system
1. Turn o power to all boilers.
2. Connect all call for heat wiring to the boilers.
3. Turn on power to all boilers and turn the on/o switches to ON.
4. e boilers should now operate normally, as described in the Boiler manual.
5. e master boiler will sequence and modulate boilers as necessary to control the
water temperature.
6. e master boiler will show the number of boilers ring as well as the temperature
and heat band display. Use the UP/DOWN keys to scroll through the displays to
watch the process of starting and stopping boilers.
1. RJ45 HeatNet cable IN from master or previous
member
2. RJ45 HeatNet cable OUT to next member boiler
3. Shielded wire (3-2ire), option to RJ45 cable, Heat-
Net communications INPUT and connection for
additional boilers on the network
4. Shielded wire (option to RJ45 cable) Modbus INPUT
from building management system
5. USB cable port (for USB cable connection to a PC —
required when updating control rmware)
6. RJ45 cable from building management system, when
used
7. Plug for insertion into KN control electrical connec-
tion panel (see page 3)
8. NOT SHOWN — An optional plug-in bridge
is required to interface with building management
systems that use BACnet or LonWorks protocol.
e KN control supports Modbus protocol with no
additional components except the RS485 interface
board.
Method 1: HeatNet modulation – local control (cont.)
1

14
KN USER’S CONTROL MANUAL
Method 2: HeatNet modulation – BMS control (Basic)
For Full Register Set see page 40
2
Table 3 Modbus holding (read/write) registers
Address
Data
Type
Description Valid Values/
Range
40001 Unsigned Boiler/System Enable/Disable 0 = Disabled/O
1 = Enabled/On
40002 Unsigned System SetpointTimer (1) 0–65535 seconds
40003 Unsigned System Setpoint (1) 40°F – 220 °F
40004 Unsigned Outdoor Air Reset Enable/Disable 0 = Disabled/O
1 = Enabled/On
40005 Unsigned Outdoor Air Setpoint 40°F -100 °F
40006 Unsigned WaterTemperature at High Outside Air 60°F -150 °F
40007 Unsigned High Outside Air Temperature 50°F -90 °F
40008 Unsigned WaterTemperature at Low Outside Air 70°F -220 °F
40009 Signed Low Outside AirTemperature -35°F -40 °F
40010 Unsigned Set Clock – Month (2) 0 – 11
40011 Unsigned Set Clock – Day of Month (2) 1 – 31
40012 Unsigned Set Clock – Year (2) 0 – 99
40013 Unsigned Set Clock – Hours (2) 0 – 23
40014 Unsigned Set Clock – Minutes (2) 0 – 59
40015 Unsigned Set Clock – Seconds (2) 0 – 59
40016 Unsigned Set Clock – Day of Week (2) 1 – Monday 7
– Sunday
40017 Unsigned Set Clock – After the Set Clock Registers listed
above have been written, a 1 must be written to
this location to set the clock. (2)
1
Table 4 Boiler status ags
Bit Description Bit Description
0 Disabled 16 Reserved
1 Local Override 17 Blower Running
2 Alarm 18 Ignition Alarm
3 Failed 19 Valve Alarm
4 Member Error 20 High Limit
5 Boiler Running 21 Reserved
6 Pump Running 22 Reserved
7 Reserved 23 Software Operator
8 Reserved 24 Header Sensor not Present
9 Reserved 25 Supply Sensor not Present
10 Reserved 26 Return Sensor not Present
11 User Interlock 27 Outside Air Sensor not Present
12 Reserved 28 — —
13 Water Prove (Flow) Interlock 29 Combination Air Damper
14 Reserved 30 Master Boiler
15 Main Valve 31 Present (Boiler Detected)
Overview
1. is method uses an RS485 digital communications cable
with the Modbus protocol to control a boiler or HeatNet
network.
2. e boiler or boiler network will operate as in the HeatNet
local control method (Section 1 of this manual). But, instead
of the HEAT DEMAND input, a soware form of the
HEAT DEMAND input is used (address 40001 — Boiler/
System Enable/Disable).
3. e System Setpoint Timer needs to be loaded periodically
to allow the HeatNet system to revert to local control from
the master boiler in the event communications is lost.
4. e Modbus protocol allows writing and reading registers
using Modbus commands. An optional BACnet or LonWorks
bridgemodule can be used toconnect the Modbusnetwork
to a BACnet or LonWorks network.
5. is method allows enabling and disabling the boiler or
HeatNet system; changing setpoints; and reading boiler
status or temperatures remotely, using digital commands
from a Building Management System.
6. emasterboilerassumesthe roleof MEMBER,RTU,192Kb,
8 bits, Even Parity, 1 stop bit, when connected to a BMS.
7. e Member Boilers should not be connected to a BMS
system other than to view read-only addresses.
MODBUS registers
1. See Table 3; Table 4; and Table 5 for register requirements.
2. e system setpoint timer and system setpoint work in
tandem to externally control the operating setpoint.
3. e setpoint (countdown) timer should be loaded with
a timeout value (in seconds) prior to writing the system
setpoint.
4. When the timer reaches zero, the control assumes that the
BMS is no longer operating and the local setpoint (saved on
the master control) is reloaded.
5. is is a fail-safe feature used to help safeguard the system
in case of BMS failure.
6. If the setpoint timer is not wrien, a default timeout value
of 60 seconds is assumed.
7. To write the system clock, registers 40009 – 40015 must
rst be loaded with the correct date and time. en, a 1
must be wrien to register 16 to write the date and time to
the system clock.

15
KN USER’S CONTROL MANUAL
Method 2: HeatNet modulation – BMS control (cont.)
2
Table 5 Modbus input (read-only) registers
Address
Data
Type
Description Valid Values/
Range
30001 Unsigned Boilers Running 0 – 16
30002 Unsigned Modulation (% BTU Load) 0 – 100
30003 Signed Header / SystemTemperature 32 – 250 °F
30004 Signed SupplyTemperature 32 – 250 °F
30005 Signed ReturnTemperature 32 – 250 °F
30006 Signed Outside AirTemperature -40 – 250 °F
30007 Signed Spare Input 1 -32768 to 32767
30008 Signed Spare Input 2 -32768 to 32767
30009 Unsigned Clock – Month 0 – 11
30010 Unsigned Clock – Day 1 – 31
30011 Unsigned Clock – Year 0 – 99
30012 Unsigned Clock – Hours 0 – 23
30013 Unsigned Clock – Minutes 0 – 59
30014 Unsigned Clock – Seconds 0 – 59
30015 Unsigned Clock – Day ofWeek 1 – Monday 7 –
Sunday
30016 –
30047
Unsigned Boilers 1 – 16 status ag (32-bit) registers.The
upper 16-bits of each 32-bit register is stored at
odd numbered addresses 30016 –30046.The
lower 16-bits of each 32-bit register is stored at
even numbered addresses 30017 – 30047.
See the Boiler
Status Flags
Table Below
30048 –
30079
Unsigned Boilers 1 – 16 runtime (32-bit) registers.The
upper 16-bits of each 32-bit register is stored at
odd numbered addresses 30048 – 30078.The
lower 16-bits of each 32-bit register is stored at
even numbered addresses 30049 – 30079.
When the upper and lower registers are combined
they form a 32-bit unsigned integer that is the
number of seconds that the boiler has been
running. For instance: (((Register 29) * 65536)
+ Register 30) = Boiler 1 runtime in seconds.
Boiler 1 is the master boiler. Boilers 2 – 16 are
member boilers.
0–4294967295
seconds
BACnet or LonWorks protocols
1. Install the correct bridge to adapt to building management
systems using BACnet or LonWorks protocols.
2. e bridge translates the BACnet or LonWorks input to
the Modbus protocol for compatibility with the HeatNet
controls.
Wiring and set-up
1. Wire and set up the master boiler and member boilers exactly
as for HeatNet modulation — local control applications.
See page 5.
2. ALL control parameters must be set up just as for the local
control method.
3. e ONLY dierence in setup is the termination DIP switch
seings. Use the seings for Modbus communications given
in Table 1.
4. Connect communications cables (RJ45 or shield-wire
cables) between the control communications boards as for
the local control method.
5. Verify network operation BEFORE connecting the building
management system.
Connect the BMS cable
1. DO NOT connect the building management system cable
until the boiler network has been proven to operate inde-
pendently. e system is designed to revert to local control
by the master boiler should communications with the
building management system be lost.
2. Turn o power to the master boiler.
3. See Figure 10. Connect an RJ45 cable to the BMS input
port, item 6. Or use shielded wire cable, connected to
terminal block, item 3.
Verify BMS/HeatNet operation
1. Turn on power to the master boiler.
2. Allow the master boiler to initialize.
3. Verify operation with the building management system.

16
KN USER’S CONTROL MANUAL
Method 3: External 4-20ma control
3
Overview — control setup sequence
Follow the Boiler manual — Install the boilers according to the KN
Boiler manual before aempting to set up the control system.
1. is method can be used for from 1 to 5 boilers.
2. Install all boilers per the Boiler manual.
3. Close the external gas valve on every boiler.
4. Wire all boilers following the guidelines in this section.
5. DO NOT install a header sensor on any of the boilers.
6. Disconnect the wires to the boilers’ Remote Enable terminals (and any override
wiring to Heat Demand or DHW Demand terminals) to ensure there will be no
call for heat while proceeding.
7. Set the boilers’ control parameters using their display/keypads.
8. Follow the instructions in the Boiler manual to start up each boiler before
proceeding further.
9. Finish by reconnecting call for heat wiring, then operating the complete system to
verify operation in all modes.
Connect 4-20mA wiring
1. See Figure 16 for wiring from the 4-20mA controller. e control must provide
the 4-20mA signal and a contact for each boiler to enable its operation by closing
across the Remote Enable contact.
Power supply (120 VAC)
1. See Figure 11 and Figure 12.
2. Connect minimum 14awg copper wire to the power connection as shown in
Figure 12.
3. Install a fused service switch, mounted and installed in accordance with all
applicable codes.
Figure 11 Electrical connection board (see item 10,
page 3 for location — Also see the wiring
summary illustrations on the next pages)
Figure 12 120VAC power service terminals on electrical
connection board — See Figure 15 for
location of the power terminal strip
Electrical shock hazard — Disconnect all electrical power
sources to the boiler before making any electrical connections.
Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation!
Verify proper operation aer servicing.
Failureto comply with theabovecouldresultin severepersonal
injury, death or substantial property damage.
e 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 to CSA C22.1 Canadian
Electrical Code Part I if installed in Canada. Install a separate
120 volt 15 amp circuit for the boiler. A properly rated shut-
o switch should be located at the boiler. e 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 eld 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.

17
KN USER’S CONTROL MANUAL
Method 3: External 4-20ma control (continued)
3
Figure 13 Wiring the boiler circulator using a circulator
relay (required for motors over 1/4 hp)
Figure 14 Wiring the boiler circulator using a relay or
starter (required for motors over 1/4 hp)
Circulator wiring
Postpurge circulator (KN-2 only)
• The circulator shipped installed with the boiler can-
not be used for system circulation. It must be used as
supplied from the factory. It circulates water aer the boiler
stops ring to prevent potential damage from heat pocketing
in the top of the heat exchanger.
• epostpurgecirculatoris factory-piped and pre-wired. Do
not change the usage, the wiring, the location or the piping.
Boiler circulator
• See the Boiler manual for circulator piping.
• Figure 13, Figure 14, and Figure 15 show wiring of the Boiler
circulator (or boiler/system circulator) to the terminal strip
of the KN-2 electrical connection board.
• DO NOT directly connect a circulator with a motor larger
than 1/4 hp. For larger motors, install a circulator relay or
motor contactor . Figure 13 and Figure 14 show the correct
ways to install the boiler circulator using a relay or motor
starter.
(KN-2 only)
Figure 15 Circulator wiring terminal strip (see Figure 11
for location) — Also see the wiring summary
illustrations on the next pages)

18
KN USER’S CONTROL MANUAL
Method 3: External 4-20ma control (continued)
3
4-20mA operation
1. A 4.02 mA current signal will start the boiler, at low re. A
20mA signal will cause the boiler to go to full input.
2. Between these input signal limits, the boiler modulates. e
boiler ring rate percentage is equal to the percentage of the
signal between 0 and 20 mA. Example, a signal of 12 mA is
60% of 20 mA, so the boiler ring rate would be 60% of max.
3. In addition to the 4-20mA signal, the remote controller
must also close a contact across each boiler’s Remote
Enable contact in order for the boiler to re.
4. See Figure 16 for wiring. Notice that the boiler 4-20mA
terminals are wired in series.
When using the 4-20 mA input for direct modula-
tion, the maximum modulation the boiler can
obtain when rst starting is equal to the;
ADVANCED SETUP: MODULAR BOILER:
MOD MAX – LAST FIRE:. e timer value
ADVANCED SETUP: MODULAR BOILER:
ADD BOILER DELAY is used in conjunction to
limit the modulation for this amount of time. Once
the boiler has red and the ADD BOILER DELAY
time expires, the full modulation is available.. When
the boiler is operating under these conditions a
blinking * is displayed. is is a protective means
for extending the life of the heat exchanger which
mayconsistentlybeexposed tothermalstress.
IAR (Indoor Air Reset) wiring —
apply ONLY if using space heating
override mode
• IAR can only be used if one or more of the boilers is wired
and piped for override operation. Override would occur
when a contact closed across the Heat Demand terminals.
While this contact is closed, the boiler will operate based on
local control, including feedback for IAR if wired.
• If override operation will be used, and you want to operate
with IAR when in override mode, follow the instructions
under Method 1 in this manual to wire for IAR.
Sensor wiring
• Header sensor cannot be used when the boilers are
congured for remote operation by a 24-mA source.
• Outdoor reset application can be done only in
override mode — To operate with outdoor reset,
purchase and install an outdoor sensor. Mount the sensor
such that it is shielded from direct sunlight if possible and
not likely to be covered by snow dris or debris. Connect
the outdoor sensor leads to the master boiler’s electrical
connection board as shown in Figure8. (Member boilers
couldhavetheir ownoutdoorsensorif they will be operated
inoverridemodebyclosingthe HeatDemandterminals.)
• Return water temperature sensor — e return water
temperature sensor is optional, only needed if you want
to automatically control the boiler postpurge pump cycle
time. Install the sensor in a well in the boiler return piping.
Connect the sensor leads to the electrical connection board
as shown in Figure 8. Each boiler requires a return water
temperature sensor.
• Sensor wiring, return water sensor — Firmware
Version 2.5 and greater monitors the temperature
dierential (Delta T) across the heat exchanger. If the Delta
T exceeds the seing, the input to the boiler can be
optionallylimited.
DHW wiring — ONLY if using DHW
override mode
• The boiler (or boilers) must be piped with isolation
valves and wired for override operation. Override of
the 4-20mA input will occur if a contact closes across the
boiler’s DHW Demand terminals.
• To operate the boiler for domestic water heating with a
storage tank, install and pipe the tank according to the
tank manufacturer’s instructions and the recommended
piping diagrams in this manual. Consult the factory for
applications not covered.
• e circulator used for DHW must be operated by a
circulator relay or zone controller that is activated when the
tank aquastat calls for heat.
• Connect the tank aquastat terminals across the DHW
DEMAND terminals on the master boiler’s electrical
connection board as shown in Figure 7. (Member boilers
could be connected to tank aquastats if they are piped
appropriately and intended to operate in override mode.)
External interlocks
5. Wire external limits and ow switch, when used, as shown
in Figure 17.
Overrides — Control priorities
1. e KN control can provide override operation for any or
all member boilers. is requires the boilers be piped with
appropriate isolation piping and controls.
2. OverrideisdonebyclosingacontactacrosstheHeatDemand
or DHW Demand terminals of any boiler. ese priority
inputs override all 4-20mA input controls to the boiler.
3. DHW Demand — e DHW Demand closure takes
priority for ALL boilers, including the master and all
members. When DHW Demand closes, the boiler or
boilers immediately switch to DHW operation, including
seing the water temperature to the DHW Setpoint.
4. Space heating, Heat Demand — If any member boiler
sees closure across its Heat Demand terminals it will
begin operation in space heating mode independently of
commands from the 4-20mA input source.
Do not wire boilers for override operation unless
the piping design provides automatic isolation of
the overriding boilers.
Override operation control setup — Boilers
must be set up with operating parameters
necessary during their override operation; i.e.,
local setpoint, DHW setpoint, etc.
5. Summary — priority sequence is:
Priority 1 = DHW Demand
Priority 2 = Heat Demand
Priority 3 = 4-20mA Input/Enable

19
KN USER’S CONTROL MANUAL
Method 3: External 4-20ma control (continued)
3
Figure 16 KN wiring summary — wiring to electrical connection board

20
KN USER’S CONTROL MANUAL
Method 3: External 4-20ma control (continued)
3
(KN-2 only)
Figure 17 KN wiring summary — wiring to electrical connection board, continued (see Figure 7 for terminal strip locations)