Mestek HeatNet V3 User Manual

KNV3-0214

Cast Iron Condensing Boilers

Models

KN-20, KN-26

Control adjustment and operation instructions
for Advanced Thermal Hydronics firmware
version 1.08

This instruction manual applies only to Advanced
Thermal Hydronics firmware version 1.x on version

3.x control boards. Current firmware is backwards
compatible with version 1.x & 2.x boards, but some
current features may not be available. To replace
firmware on an existing boiler, contact the factory
to obtain the original firmware file or for assistance
in applying current firmware to an olde
control board.

Also read and follow:

KN-Series Gas Boiler Installation
and Operating Instructions

KN-6, KN-10, KN-16,

and KN-30

V3

r version

er/technician. Read and follow this manual, all supplements and related

er/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

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.

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

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 injur

the burner, resulting in possible severe personal injur
free air supply. Follow the instruction manual procedures to duct air to the boiler air intake. If the boiler has been contaminated by operation

free air supply. Follow the instruction manual procedures to duct air to the boiler air intake. If the boiler has been contaminated by operation
with contaminated air, follow the instruction manual guidelines to clean, repair or replace the boiler if necessary.

with contaminated air, follow the instruction manual guidelines to clean, repair or replace the boiler if necessary.

x these instructions near to the boiler/water heater. Instruct the building owner to retain the instructions for future use b

x these instructions near to the boiler/water heater. Instruct the building owner to retain the instructions for future use b

service technician, and to follow all guidelines in the User’s Information Manual.

service technician, and to follow all guidelines in the User’s Information Manual.

e boiler can only be operated with a dust-

e boiler can only be operated with a dust-

TABLE OF CONTENTS HeatNet Control V3 1.xx-1

TABLE OF CONTENTS

TABLE OF CONTENTS .............................................................................................................................. 2

Introduction ............................................................................................................................................... 4

THE KN-SERIES HEATNET CONTROL ................................................................................................................................................... 4

Features & Specifications ......................................................................................................................... 6

STANDARD FEATURES OVERVIEW ........................................................................................................................................................ 6

Specifications ............................................................................................................................................ 8

Components & Accessories ..................................................................................................................... 9

PART NUMBER COMPONENT ........................................................................................................................................................... 9

SETUP & OPERATION ............................................................................................................................. 10

BASIC MULTI BOILER SYSTEM OPERATION .......................................................................................................................................... 10

MIXED BOILER TYPES USING PRIORITY SETS ...................................................................................................................................... 11

MIXED BOILER SYSTEM OPERATION ................................................................................................................................................... 11

START/STOP PRIORITY CONDITIONS .................................................................................................................................................. 13

SELECTING MIXED BOILERS .............................................................................................................................................................. 14

MIXED SYSTEM TYPE 1: HIGH SYSTEM TURNDOWN ............................................................................................................................ 14

MIXED SYSTEM TYPE 2: CONDENSING / NON-CONDENSING .................................................................................................................. 18

BASE LOADING, RELAY CONTROL ..................................................................................................................................................... 20

SETTING UP BASE LOADING ................................................................................................................................................................ 22

Heating Control Methods ........................................................................................................................ 23

HEATING METHOD 1 ......................................................................................................................................................................... 23

HEATING METHOD 2 ......................................................................................................................................................................... 23

HEATING METHOD 3 ......................................................................................................................................................................... 23

HEATING METHOD 4 ......................................................................................................................................................................... 23

HEATING METHOD 5 ......................................................................................................................................................................... 23

OPERATING LIMIT ............................................................................................................................................................................. 23

INPUT PRIORITIES ............................................................................................................................................................................. 23

HEATING METHOD 1 HEAT DEMAND ............................................................................................................................................... 24

HEATING METHOD 2 STAGE CONTROL T1-T2 ................................................................................................................................... 25

HEATING METHOD 3 4-20MA CONTROL .............................................................................................................................................. 25

HEATING METHOD 4 AA INPUT .......................................................................................................................................................... 25

HEATING METHOD 5 MODBUS COMMUNICATIONS .............................................................................................................................. 26

Using the 4-20ma input (OPTIONAL) ...................................................................................................... 27

Circulator Pump Options ........................................................................................................................ 29

Auxiliary Function Options ..................................................................................................................... 31

Outdoor Reset ......................................................................................................................................... 32

Sensors .................................................................................................................................................... 32

Security ...................................................................................................................... .............................. 32

Diagnostics .............................................................................................................................................. 3 2

Page 2

TABLE OF CONTENTS HeatNet Control V3 1.xx-1

Communications ...................................................................................................................................... 33

Failsafe Modes ......................................................................................................................................... 33

FAILSAFE REQUIREMENTS: ....................................................................................................................................................... 33

Domestic Hot Water Methods ................................................................................................................. 35

DHW METHOD 1: DHW TANK SENSOR INPUT ................................................................................................................................ 35

DHW METHOD 1A: DHW HEATING ONLY USING A SINGLE BOILER OR A DHW MASTER AND MEMBER BOILER(S) EMPLOYING H-NET ... 35

DHW METHOD 1B: COMBO DHW AND SPACE HEATING USING A MASTER BOILER AND MEMBER BOILER(S) EMPLOYING H-NET ............. 36

DHW METHOD 2: DHW HEADER SENSOR INPUT ............................................................................................................................. 37

DHW METHOD 3: SPACE HEATING WITH DHW OVERRIDE ............................................................................................................... 37

DHW METHOD 4: DHW USING DIRECT CONTROL ............................................................................................................................ 38

Wiring Connections ................................................................................................ ................................. 39

Calibration ................................................................................................................................................ 50

Log Entry .................................................................................................................................................. 51

Default Settings & Menu Item Descriptions — SETUP .......................................................................... 52

Default Settings & Menu Item Descriptions — ADVANC ED SETUP ..................................................... 56

MODBUS Communications ..................................................................................................................... 61

Troubleshooting ...................................................................................................................................... 69

ontro

KN HeatNet C

l Run Screen ............................................................................................................. 74

* Status Information ................................................................................................................................. 82

STATUS INFORMATION SCREENS ........................................................................................................................................................ 82

KN HeatNet Control Menu Tree — Advanced Thermal Hydronics 3V .................................................. 75

KN HeatNet Control Advanced Menu Tree — Advanced Thermal Hydronics V3

.. 73

....................................

Worksheet ................................................................................................................................................ 77

Thermistor Resistance/Temperature Table ............................................................................................ 81

Status Screen Fault Display .................................................................................................................... 84

Line 4 Log Entries: ................................................................................................ .................................. 87

is provided only for your convenience and may be superseded by updates. It is your
responsibility to ensure that your application meets with your specifications.

ADVANCED THERMAL HYDRONICS MAKES NO REPRESENTATIONS
OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED,
WRITTEN OR ORAL, STATUTORY OR OTHE
INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR
PURPOSE.

http://www.knseries.com/

RWISE, RELATED TO THE

The Advanced Thermal Hydronics name and logo, Mestek name and logo, Information contained in this publication regarding device applications and the like
KN, HeatNet, and H-Net name and logo are registered trademarks of
Mestek, Incorporated in the U.S.A. and other countries.

BACnet is a regist ered trademark of ASHRAE. LonWor ks is a registered
trademark of Echelon Corporation. All trademarks mentioned herein are
property of their respective compan ies.

© 2012, Mestek Technology Incorporated, Printed in the U.S.A., All Rights
Reserved.

Page 3

FEATURES & SPECIFICATIONS HeatNet Control V3 1.xx-1

The HIGH LIMIT circuit is independent of

Introduction

the control and shuts down the ignition
control and the boiler if the control board or
other component of the boiler was to

The KN-Series V3 HeatNet Control

The KN-Series V3 boiler control is the third generation of

malfunction. The control will continue to
function and report the fault, but its ability to
control the boiler will end.

the HeatNet control platform. Control hardware has been
added to make use of many new heating applications. These
new features are outlined in the Features & Specifications
section.

Each KN-Series boiler employing this control can function
as either a master or a member. This allows one boiler
(Master) to be in control of target temperature. The other
boilers (Members) only respond to the commands issued by

The KN-Series boiler control is designed to provide the KN­Series of boilers with an integrated boiler management
system on every boiler. Designed for the Air-Fuel coupled

the Master. If using an external control, all boilers can be
setup as members. The following will define the roles of
master and member.

KN-Series boilers, the KN-Series HeatNet control provides

for optimized heating efficiency without the need for a “wall
mount control”. Since the KN-Series modular control

method is based on digital communications, analog control
signals are not required. Although the use of analog control
signals is still supported (4-20mA control loops and 0-10vdc
control voltages), a higher level of control precision,
repeatability, and feedback is gained with digital
communications control.

With the KN-Series, optimized heating efficiency is
accomplished by setting the Modulation Maximum (Mod­Max) setting to exploit the inverse efficiency curve. This
value can be adjusted so that as each boiler is added, it
operates at its maximum turndown. This allows the
maximum number of boilers to operate at their lowest
inputs, until all boilers are firing. Once all boilers are firing,
full range modulation control is allowed. An outdoor reset
function is also provided to assist in the optimized heating
efficiency of the KN- Series boilers.

Master

A boiler becomes a master when a temperature sensor is

connected to the J10 “SYSTEM HEADER” terminals. The

sensor is auto-detected.

The master senses and controls the common system
header/loop water temperature using a system setpoint. It
uses any boilers it finds (over the H-Net communications
cable) to accomplish this. It can also monitor the Outside
Air (OA) temperature to provide outdoor reset functionality.

Only one master is allowed in a system.

When operating as a master, the boiler provides a control
method using a PID algorithm to regulate water
temperature. This algorithm allows a single boiler (Master),
or multiple (Master + Member) boilers.

Figure 1 Heat band

The KN-Series boiler with the KN-Series H-Net control, can
be operated in multiple ways:

1. As a stand-alone boiler.

2. A boiler in a Boiler Network using the HeatNet

(H-Net

®

) protocol.

®

3. A member boiler to a boiler management system with

multiple input control methods.

The primary purpose of the control is to maintain the boiler
water temperature at the supply or the header sensor using a
target setpoint. While performing this task, the control also
monitors dedicated external limits in a limit string and
provides an orderly shutdown and fault indication in the
event of a tripped limit. The monitored limits include a
HIGH LIMIT AQUASTAT, LOW WATER CUTOFF,
GAS PRESSURE, FLOW, IGNITION CONTROL fault,
GAS VALVE alarm, VARIABLE FREQUENCY DRIVE
alarm, and other optional or user selectable limits.

BOILERS

UPPER HEAT

BAND LIMIT

SETPOINT

LOWER HEAT

BAND LIMIT

WATER

TEMPERATURE

STAGED

OFF

Boilers Staged

ON

Time

The control algorithm is based upon a Heat Band, at the
center of which is the setpoint. While below the Heat Band,
boilers are staged on and modulated up until the Heat Band
is entered. Once in the Heat Band, modulation is used to
maintain setpoint. Boilers are shut down only when the top
of the Heat Band is breached. Timers are also used to
prevent short cycling.

While staging the boilers on, a modulation clamp

ADVANCED SETUP: MODULAR BOILER SET:
MOD MAX-LAST FIRE is used to hold the boilers at a

lower fire rate until the last boiler is fired. Once the last
boiler fires, the modulation clamp is removed and all boilers
are allowed to fire above this clamped percentage up to

Page 4

FEATURES & SPECIFICATIONS HeatNet Control V3 1.x

100%. This “boiler efficiency” clamp is defaulted to 70%

and thus limits all of the boilers individual outputs to 70%
until the last boiler fires. All running boilers modulate up
and down together, always at the same modulation rate. As
a general rule, this percentage should be no lower than twice
the minimum turndown to minimize short cycling.

When additional boilers are needed to achieve setpoint in
the system, the Master boiler employs an ADAPTIVE
MODULATION algorithm to prevent over firing of the
system. The Master communicates over the H-Net to view
the exact status of each Member boiler. When a new boiler
is added, the Master boiler adjusts the system modulation
rate lower to compensate for the BTUs that will be
introduced by the newly added boiler. This adjustment
occurs when the newly added Member boiler enters its ON
CALL state (default setting). This can be changed to PILOT
when the new boiler is called using the menu:

ADVANCED SETUP:ADAPTIVE MOD:DROP
DOWN. Once the Main Valve (on the newly added boiler)

is opened, and the DELAY RELEASE timer equals zero,

the PID algorithm is allowed to control the system

modulation. Setting the DELAY RELEASE timer will

allow some “soak” time of the newly added boiler before

releasing modulation control to the PID.

In a stand-alone installation the Member typically receives
its command signals internally and operates based upon the
outlet water temperature input and the established settings in
the menu (Local Set-point) to start/stop the burner, and/or to
modulate the firing rate. If the operating limit is exceeded,
or if an interlock trips, the boiler is shut down. As in a
multi-boiler system, a stand-alone Member boiler is also
capable of receiving inputs from an external control system.

When using the H-Net network cable in a Master/Member
system, the system setpoint is sent from the Master as a
digital signal, along with the modulation value to control
firing rate. It also receives its command to start or stop over
the H-Net cable. Also, the SYSTEM CLOCK only needs to
be set on the MASTER. The Master will then set the time
on all member boilers.

If not using the H-Net protocol (cable), an external control
can send a 4-20ma signal along with a 4-20ma enable signal
to control the firing rate or setpoint. The boiler may also be
treated as a 2-stage boiler or an ON-OFF boiler using the
dedicated T-inputs.

The ADAPTIVE MOD menus are disabled

on a Member boiler, but are still visible.

Member

If a “SYS/DHW HEADER” sensor is not connected to J10,

a boiler always defaults to the role of Member.

The Member boiler can operate as part of a multi-boiler
system or as a stand-alone unit.

In a multi-boiler system the Member typically receives its
command signals from a designated Master-boiler. It is also
capable of receiving inputs from an external control system.
The boiler responds to these signals, to start/stop the burner,
and/or to modulate the firing rate. The outlet water
temperature is also monitored. If the outlet temperature
approaches the operating limit temperature setpoint
(adjustable), the boilers firing rate is limited and its
modulation value is reduced to minimize short-cycling. If
the operating limit is exceeded, or if an interlock trips, the
boiler is shut down. When connected with a network cable,
in a Master/Member role, the Members' status is
interrogated by the Master boiler.

Page 5

FEATURES & SPECIFICATIONS HeatNet Control V3 1.x

firmware program that always remains resident so that a

Features & Specifications

factory program can be restored. Primary loading is
with a flashdrive.

HeatNet Version 3.x Discontinued
Features

1. With this hardware release the service power,
switched power, and the power switch connector
have been removed. These were available on
prior versions of the HeatNet control. Upgrading to
this control fr om prior versions will require some
wiring changes using an upgrade kit.

2. The J10B input is no longer supported for pr oving
the damper. Damper proving switches will need to
be wired to J12B. J10B wires from the prove
switch should now be connected to J12B.

3. If a stack sensor is used with this version, the
alarm silence switch can not be connected and the
disconnected wires should be terminated
appropriately.

Silencing the alarm can be done by holding the
BACK and SELECT keys down at the same time.

Hardware Version 3.x Control
Additional Features
(Identified by circuit board color: BLACK)

1. Support for (2) Circulator pumps. Two rotation modes

are provided: Based on system runtime or system pump
runtime hours. Pump failure switchover/retry mode.

2. Warm weather shutdown, (2) pump jog and local pump

jog to keep pumps from seizing.

3. The Modbus, BACnet or LonWorks communications

port can be accessed concurrently with the USB port
(HeatNet Control Pro). The BACnet, LonWorks, or
Modbus connections do not need to be disabled to use
the USB ports.

4. The DHW pump and the Local Pump relay connections

now provide a normally closed contact. This allows for
the use of a power open/power close valve.

5. Support for 5ma 0-10v control signals using third party

controls.

6. Support for (2) display types: Vacuum Florescent and

Color LCD using the same 20 pin ribbon cable.

7. System Return sensor input.

8. Enhanced bootloader and firmware storage. One

firmware storage location for user updates. One

9. Support for High Efficiency Ametek blowers.

10. 32 bit Microcontroller operating @64Mhz with 5-stage

pipeline, and prefetch cache.

11. (3) stage control relay outputs for TBD applications.

12. Backwards compatible with existing HeatNet versions

1.x and 2.x controls and applications.

13. Support for 135 Ohm control actuators.

Standard Features Overview

1. Five levels of external control inputs, including

modulation and staging that provide application
flexibility.

2. Digital Communications Control (analog 4-20ma and 0-

10vdc control supported, but not required).

a. Boiler to Boiler : HeatNet (H-Net)
b. Building Management System (MODBUS,

Optional BACnet or LonWorks) to Boiler

3. Distributed control using the HeatNet (H-Net) protocol

for up to 16 boilers. Eliminates the need for “wall
mounted” controls.

4. Analog Control 4-20ma and 0-10vdc (5mA minimum

current) signals supported.

5. System/Boiler operating status text display

6. Interlock, Event, and System logging with a time

stamp.

7. Advanced PID algorithm optimized for the KN-Series

boilers.

8. (4) Dedicated temperature sensor inputs for: Outside

Air Temperature, Supply (Boiler Outlet) Temperature,
Return (Boiler Inlet) Temperature, and Header
(Common System Supply) Temperature.

9. Automatically detects the optional temperature sensors

on power up.

10. Menu driven calibration and setup menus with a bright

(Adj.) 4 line Vacuum Fluorescent Display.

11. (8) Dedicated 24vac interlock monitors, and 8 dedicated

120vac system monitors used for diagnostics and
providing feedback of faults and system status.

12. Multiple circulator pump control modes.

Page 6

FEATURES & SPECIFICATIONS HeatNet Control V3 1.x

13. Combustion Air Damper control with proof time,

support for a common combustion air damper.

14. USB/RS485 network plug-in to allow firmware updates

or custom configurations.

15. Optional BACnet or LonWorks interface.

16. Alarm Relay dry contacts, and Audible Alarm.

17. Runtime hours, and Cycles (based on Main Valve

Open).

18. Outdoor Air Reset with programmable setpoint and

ratio.

19. Time of Day clock to provide up to (4) night setback

temperatures.

20. Failsafe mode when a Building Management System is

controlling setpoint. If communications is lost, the
boiler/system automatically transfers to local boiler
setpoint control.

21. Rotation Methods(Lead-Lag): True Rotation (based on

boiler runtime)is default. First On First Off (FOFO),
Last On First Off (LOFO) and MIXED are optional.

22. Programmable password protection to secure the

programmable settings.

24. Freeze Protection allowing automatic starting of

boiler(s) using (2) Failsafe modes.

25. Adaptive Modulation. When additional boilers are

called, the Master adjusts all boilers fire rates to
compensate.

26. Mixed boiler types in a system.

27. Support for Domestic Hot Water (DHW) using a 10k

Sensor or a dry contact input from a tank thermostat.

28. Domestic Hot Water relay for use with a pump or

valve.

29. On-board power and socket for Protocessor

BACnet/LonWorks module.

30. HI/LO relay control option from connector J4

31. Resettable Fused interlock power circuit.

32. Additional terminal connector for H-Net shielded cable.

33. Backwards compatible to Version 1.x hardware.

34. Communications board integrated with the main board

from version 1.x control.

35. Base Loading of (1) boiler.

23. Remote 4-20mA setpoint control using a mapped

setpoint range to the 4-20mA control signal.

Page 7

FEATURES & SPECIFICATIONS HeatNet Control V3 1.x

Specifications

Control Microprocessor based PID

modulating control ( NOT a
safety limit )

Environment -40 °F to 140 °F, <90% RH

non-condensing

Input Power 24 VAC, 500 ma

Relays System Pump, Damper,

Circulator, Alarm, DHW
Pump (v2.x), 8A 250 VAC
resistive

K8 on J4.2 &.6 for Base

Loading version 2.x Control

AC Interlocks 24 VAC – 120 VAC input

Control Inputs AA, Heat Demand, 4-20ma

Enable, OA override, T1-T2
(dry contact inputs)

4-20mA, 0-10 VDC

Dimensions 9” wide: 6” high : 2” deep

Temperature Sensors NTC thermistor, 10K @ 77

°F, 335.67K @ -40 °F, 185
@ 150 °F ,+/- 1 qF

USB 1.0

RS485 MODBUS Modbus RTU

Boiler-to-Boiler HeatNet (H-Net)

Network Optional LonWorks,

BACnet available bridge to
MODBUS port

Page 8

Components & Accessories

Part Number Component

02-4297 KN-Series Control Board Version 3.x

02-4278 Graphics Display Board

02-3926 Temperature probe (bullet type, 1x.250 inch) ACI/10K-CP-BP

02-4283 Supply, Header, Return Sensors ACI 10k-CP-I-NW

02-4285 Sensor with well ACI CP-I-2.5”

02-4286 Sensor with well ACI CP-I-4”

02-4281 Strap-on sensor ACI 10k-CP-S

02-4280 Outside Air Sensor with Housing ACI 10k-CP-O

Installation & Operation Manual

40-5409 RJ45 Communications Cable Assembly, 25 feet

40-5411 Ribbon Cable Assembly (Display Control)

58-1833 10k ohm Calibration Resistor

40-5408 USB Cable Assembly, 6ft

60-5631 Terminal Block Screwdriver

Contact Factory MODBUS to BACnet bridge

Contact Factory MODBUS to LonWorks bridge

Page 9

SETUP & OPERATION HeatNet Control V3 1.x

RUNTIME setting in ADVANCED SETUP:FIRING

SETUP & OPERATION

Basic Multi Boiler System Operation

For boiler system setup/installations please

refer to Refer to the 2008 ASHRAE
Handbook, CH12 or later revision.

A basic multi boiler system typically uses boilers of the
same size and type. With HeatNet, this includes (1) Master
and (1-15) Member boilers. The boilers are connected
together using an H-Net communications cable effectively
creating (1) boiler. This allows the system heating BTUs to
be evenly distributed amongst all of the boilers. (See: Figure
36, Typical Single Boiler System, page 46).

Figure 2 Basic multiple boiler system

A basic multi boiler system can be configured using the
boiler menus to create custom systems/features. These

features are best described in the section: Default Settings

& Menu Item Description, page 52. Along with these
menu items are hardware support for many
auxiliary functions.

Once the system has been properly setup (all default menu
values used and H-Net addresses assigned), the system is
enabled by placing the REMOTE/LOCAL switch to the
LOCAL position on the Master boiler. All Member boilers
must have their respective switches in the REMOTE

position. When the Master boiler’s Heat Demand input

(LOCAL switch) closes, the system becomes operational
and will fire as many boilers as it needs to maintain the

header water temperature’s setpoint.

When a boiler is to be fired in a multi boiler system (header
water temperature is below the heating band), the Master
checks the HeatNet boilers it has available. Then the Master
checks if a Lead Boiler is to be used (LEAD BOILER > 0).
The Master boiler then looks at which type of firing rotation
it has selected: LOFO, FOFO, TRUE (runtime), or MIXED.
In our example we will use the TRUE (runtime) rotation
since it is the default.

The Master now checks all of the runtimes to determine
which boiler has the least runtime based on the MIN

MODE:. The MIN RUNTIME setting is the minimum
runtime interval in hours that is used to compare boiler to
boiler runtimes.

Once the boiler to fire has been determined, the Master
sends the command over the H-Net cable to fire that boiler
and resets the ADD BOILER delay timer to prepare for the
next boiler to fire. If the header water temperature is still
below the heating band and the ADD BOILER delay timer
has expired to zero, the process is repeated until the header
water temperature enters the heating band.

When a boiler receives a command to fire it:

1. The system pump relay is enabled and the H-Net

control displays 'Flow Wait' until the flow-switch closes
between J11A, 1 & 2 within the programmed time
(10seconds).

2. All elements in the interlock string, terminated between

J11A and J11B, must be closed before the sequence is
allowed to continue.

3. If all interlocks are closed relay K5 is enabled to

command the combustion-air damper open (If used).
The H-Net control displays 'Damp: Wait' until the
damper end switch closes.

4. Relay K6 is enabled energizing the local pump (if

used). The H-Net control commences its 'Flow-Wait'

timer (adjustable 10–240 sec.). The flow switch contact

is checked on terminals J11B, 5 &6.

5. With all the interlocks closed, the boiler start relay K1

is enabled and energizes terminal 6 on the ignition

control. This signal is present on J5 Boiler Start

Operator.

6. The ignition control begins its cycle and provides an

output signal from terminal 4 to the H-Net control J5
Blower. The H-Net control responds and provides an

output signal to the VFD which sets the blower to the
programmed pre-purge speed. If an Ametek blower is
used, a soft start speed is applied before the pre-purge
speed.

7. After air-flow is established the ignition control waits

for the air switch to close. When the air switch closes it
provides an input to terminal 7 and pre-purge timing
commences. The H-Net display indicates 'Pre Purge'.

8. When purge is complete the ignition control energizes

the pilot gas valve from terminal 8, and the spark
generator from terminal 10, beginning a 10-second Pilot
Flame Establishing Period (PFEP). The H-Net control

responds to J5 Pilot Valve and provides an output

signal to the VFD which sets the blower to the
programmed ignition speed. The H-Net display
indicates 'Pilot'.

9. At the end of the PFEP the spark generator is de-

energized. If the pilot flame is detected, by the UV
scanner, the ignition control energizes the main gas

valve from terminal 9 to J5 Main Valve. The H-Net

display indicates 'Run'.

Page 10

SETUP & OPERATION HeatNet Control V3 1.x

10. If main-flame is detected the H-Net control holds the

burner at the low-fire rate for the MODULATION
DELAY time period. After this timer expires, the PID
allows the boiler to modulate and places the boiler into
the running state.

As boilers are added to the system settings in the ADVANCED
SETUP:ADAPTIVE MOD:DROP DOWN menu determines
when the modulation rate drops down to compensate for the
newly added BTUs. For the drop down to be active one
boiler needs to be running when a new boiler is added (see:
Introduction: The KN-SERIES H-Net Control: Master).

If all boilers are firing, the modulation rate is released to go
to 100%. If all boilers are not firing, the modulation is
limited to the MOD-MAX clamp value. The MOD-MAX
clamp is used to keep the boilers running as efficiently as

possible. The following Mixed Boiler System Operation:
Selecting Mixed Boilers section outlines this with examples.

NOTE: If the boiler is running as a stand-alone boiler or

is direct modulated (including the AA input),
the MOD-MAX clamp will also be in effect
for the ADD BOILER DELAY time. This is to
minimize thermal shock to the boiler.

Once the header water temperature is in the heating band,
only the modulation rate is used to achieve the target
setpoint. The system will maintain the setpoint until the load
demand increases or decreases.

As the load decreases, the header water temperature will
start approaching the top of the band. The PID now lowers
the modulation rate to the boilers, attempting to keep the
temperature within the heating band. If the system is
delivering too many BTUs, the water temperature will cross
the top of the heating band.

When the header water temperature first exceeds the top of
the heating band, the boilers are again checked for the one
with the most runtime. The selected boiler will turn off
immediately and a shed boiler delay timer will be loaded
with the delay time. This time will need to expire before the
next boiler will be stopped, but only if the header water
temperature remains above the heating band. This timer is
used to allow the header water temperature to return back
into the band when a boiler is stopped. When a boiler is
stopped there is a fixed rate of BTUs (Min Fire) that will be
removed (PID discontinuity to modulate from Min Fire to 0
BTUs on a boiler). The timer allows for this loss of BTUs.

This cycle will continue until the call for heat is satisfied or
the Warm Weather Shutdown feature is enabled.

Mixed Boiler Types Using
Priority Sets

Using the Basic Multi Boiler System Operation, a MIXED

boiler Priority method may be added to control condensing,

non-condensing, base load, or other boiler SETs in a system

together. These sets compose a system which provides for
optimal performance and economy. Having dedicated sets
of boilers gives the system engineer a tool to create many
different boiler systems.

A boiler set can be constructed by simply setting the firing
Priority on each boiler (to be in a set) at the same priority.
Setting all (example) condensing boilers to the highest
Priority of 1, and then setting all (example) non-condensing
boilers to a Priority of 2, will create (2) sets of boilers, one
condensing and the other non-condensing. Once this is
done, the Priority 1 set of condensing boilers will have a
firing order that has a higher Priority and is independent of
the other non-condensing set with the lower priority. The
boiler set with the highest Priority can then be fired based
on a conditional settings menu. The lower Priority set will
follow.

Mixed Boiler System Operation

Starting Boilers:

When a boiler is to be fired (water temp is below the heating
band), the Master checks the HeatNet boilers it has
available. The Master boiler then looks at which boilers are
returning Priority firing status (set on a boiler in:
(ADVANCED SETUP:SYSTEM:BOILER

TYPE:PRIORITY : 1). If the Start condition for the

Priority 1set is met (ADVANCED SETUP:FIRING MODE:

MODE: MIXED:SET FIRST (example), the Master or

Member boiler that is configured as PRIORITY 1, with the

lowest runtime, will be fired FIRST (example).

As long as the start condition for Priority 1 is met, all
boilers in the PRIORITY 1 set will fire based on runtime.
Once all boilers in the PRIORITY 1 set have fired, the
PRIORITY 2 set of boilers will fire based on runtime.

If the Start condition changes and/or is not met (such as
with: OA T or RET temp), the PRIORITY 2 set of boilers
will fire first/next based on runtime. This has the effect of
flipping the Priority of the sets.

Stopping Boilers:

When a boiler is to be stopped (water temp is above the
heating band), the Master checks the HeatNet boilers it has
available. The Master boiler then looks at which boilers are
returning Priority firing status (set on a boiler in:
(ADVANCED SETUP:FIRING MODE: MODE:

MIXED:SET LAST(example) If the Stop condition for

Priority 1 is met, the Master or Member boiler that is

Page 11

SETUP & OPERATION HeatNet Control V3 1.x

START PRIORITY 1
>SET : FIRST

SET : OAT < 15°F

configured as PRIORITY 1 with the highest runtime will be

stopped LAST (example). As long as the stop condition and

SHED DELAY time are met, all remaining PRIORITY 1 set
of boilers will stop based on runtime. If the Stop condition
changes and/or is not met (such as with: OA T or RET
temp), the PRIORITY 2 set of boilers will stop first/next
based on their highest runtime.

Figure 3 Mixed Boilers: Example: Condensing/Non-Condensing

A boiler’s firing Priority can be designated as such in:

ADVANCED SETUP:SYSTEM:BOILER TYPE:FIRING
PRIORITY : 1 menu on each boiler. A Priority of ‘1’ is

the highest priority, a ‘2 the lowest (default is always 2).

In the example Mixed Boilers: Condensing/Non-
Condensing, condensing boilers and non-condensing boilers

are used, but other combinations may also be used. Another
example could use (2) small boilers and set them to
Priority 1 and then use (3) larger boilers and set them to
Priority 2. Using these Priority settings (with the conditions
menu), the small boilers can run first during the shoulder
months (Spring and Fall) and the larger boilers can fire last
during the colder Winter season (base loading set).

Before the MIXED method can be used, the firing mode on
the Master boiler must be set to MIXED. ADVANCED
SETUP:FIRING MODE: MODE: MIXED. Pressing the
SELECT key when the cursor is pointing to MIXED will
enter the conditions menu. The START and STOP conditions
for starting and stopping the Priority boiler set may be
configured here. Temperatures are adjustable.

STOP PRIORITY 1

Once the conditions menu has been entered, the firing order
and stop order of the Priority 1 boiler set can be selected
based on up to (3) conditions in the conditional settings
menu. All conditional settings apply to the Priority 1 boiler
set. When the conditional settings do not apply to the
Priority 1 set, the conditional settings will apply to the
Priority 2 boiler set.

Page 12

SETUP & OPERATION HeatNet Control V3 1.x

START PRIORITY 1
>SET : FIRST

SET : LAST

Start/Stop Priority Conditions

The following is an example using mixed
condensing and non-condensing boilers:

FIRE FIRST

Condensing boilers may be configured to fire first (set to

PRIORITY 1) when:

2. The Return water temperature is below 140F and

condensing occurs. (The Master’s return water sensor

would need to be moved to the header return.)

3. The Outside Air Temperature is above a setpoint

determined by the system configuration. This setpoint
ensures that the more efficient condensing boilers run
first during shoulder months (Spring and Fall) when
minimal heating is required. Below this setpoint, larger

boilers should be brought on first to “base load” the

system.

4. Greater efficiency is required.

STOP FIRST

Condensing boilers may be configured to stop first (set to

PRIORITY 1) when:

The Return water temperature is above 140F and
condensing is minimized, thus leaving the larger lower cost
boilers running to carry the load.

1. The Outside Air Temperature is below an adjustable

setpoint determined by the system configuration. This
setpoint ensures that the larger non-condensing boilers
run during the coldest months when maximum heating
is required. Above this setpoint smaller condensing
boilers should be brought on first to run the system as
efficiently as possible.

temperature on the Master is used to provide a difference
temperature across the heat exchanger. However, the return
temperature sensor may be moved on the Master to provide
system return temp if the difference temp is not required).

STOP PRIORITY 1 SET

Selections (always the highest runtime first):

The condensing boiler set (Priority 1) has a

higher Priority to stop when one of these

conditions are met. Values are adjustable.

LAST: The condensing boilers (Priority 1) are always

stopped LAST.

OA T < 15F: The condensing boilers (Priority 1) are

stopped first when the OA temperature is less than Mixed
Boiler Outdoor Air Temperature.

RET > 140F: The condensing boilers (Priority 1) are

stopped first when the Return water temperature is greater
than the Mixed Boiler Return temperature. (This may not
applicable in most configurations since the local return
temperature on the Master is used to provide a difference
temperature across the heat exchanger. However, the return
temperature sensor may be moved on the Master to provide
system return temp if the difference temp is not required)

Start/stop settings

Any combination of Start Conditions and Stop Conditions
can be used to optimize the mixing of condensing
(Priority 1) and non-condensing boilers (Priority 2) for best
performance/economy.

The default settings for the start and stop conditions of the
condensing set are:

2. Maximum heating is required

START PRIORITY 1 SET

Selections (always the lowest runtime first):

The condensing boiler set (Priority 1) has a

higher Priority to fire when one of these

conditions is met. Values are adjustable.

FIRST: The condensing boilers (Priority 1) are always

started FIRST

OA T > 15F: The condensing boilers (Priority 1) are

started when the OA temperature is greater than the Mixed
Boiler Outdoor Air Temperature setting.

RET < 140F: The condensing boilers (Priority 1) are

started when the Return water temperature is less than the
Mixed Boiler Return temperature setting (This may not
applicable in most configurations since the local return

STOP PRIORITY 1

The default start setting always starts the condensing boilers
(Priority 1 example) first, except for the lead boiler setting.

The lead boiler will always start first if enabled, unless

there is a boiler already running (this includes a Member
boiler in LOCAL). The default stop condition setting always
stops the condensing boilers (Priority 1) last.

If prolonging the life of the heat exchanger(s) on non­condensing boilers is very important, consider starting the
condensing boilers (KN series) when the return water
temperature is below 140F.

Page 13

SETUP & OPERATION HeatNet Control V3 1.x

System

MMBTU

Effective

Turndown

MOD
MAX

KN20, KN20,

KN20, KN20, KN20

KN10, KN10,

KN10, KN10, KN10

500, 500, 500, 500,

500

The return water temperature sensor would

need to be moved from the Master’s return

inlet to the system return. The EXCHGR
DELTA may need to be adjusted in
SETUP:AUX FUNCTIONS:HEAT
EXCHANGER to prevent the Master from

going to ½ input when a high DELTA T is
reached.

This method would lead to the non-condensing boilers
carrying the load when the system temperature stabilizes
above 140F, since non-condensing boilers will start first
with the Return water temperature is > 140F. The
condensing boilers can then be stopped first when the RET
water temperature is above the 140F. Remember, any
combination of the Start and Stop conditions may be applied
for best performance and economy in the system.

Base load boilers can also be mixed in the same way as
condensing and non-condensing boilers. The base load
boiler(s) can be prioritized in one set (example, Priority 2)
and non-base load boilers (Priority 1) . The non-base load
boilers can then be set to fire first and once they are all
firing, the base load boiler would fire.

To minimize the cycling of a large base load boiler, consider
using the stop condition. Change it to the OA T < 15F
(Outside Air Temperature) condition. This setting may be
used to stop the Priority 1 boiler set when the OA T drops
below the OA T setpoint, thus leaving the large base loaded
boiler on and shutting off the condensing boilers first. This
is also true when using the OA T setting to start the
Priority 1 boiler set when the OA T is above the start
setpoint. To use temperatures as start and stop conditions,
the system design temperatures must be known.

Selecting Mixed Boilers

There are a few factors to consider when choosing which
type of boilers to use in a mixed system. These factors need
to be considered when boilers are added or shed. When
BTUs are introduced into the system by adding boilers, the
amount of introduced BTUs should be smooth (linear). If
these factors are not considered, discontinuity in BTUs may
occur when boilers are added and as a result, short cycling
will occur.

4. Desired Effective Turndown. This is the lowest

firing rate of the system relative to the maximum firing
rate of the system. The larger the value, the lower the
BTUs that can be delivered to a light load.

5. Piping.

Mixed System Type 1:
High System Turndown

The following examples are of mixed boiler systems with
high effective system turndown and fault tolerance built in.
When boiler types are the same, the system turndown is

limited to the boiler’s min input and fault tolerance is

always present. When the system has mixed boiler types,
consideration needs to be taken on what types can be mixed
properly to achieve a high system turndown and provide
some fault tolerance.

Fault tolerance allows for one boiler in the Priority 1 system
to fail and any boiler(s) in the Priority 2 system to fail and
still provide near linear (continuity) BTU response when
adding boilers. This is illustrated in the following examples
using the Boiler System Response graphs.

The KN Mixed Boiler System (examples) is advantageous
in providing low BTU input for light loads and high BTUs
for heavy loads. The effective system turndown minimizes
short cycling when light loads are present by assigning
smaller boilers to Priority 1, running them first, and then
stopping them last.

In order to achieve the high effective

turndown, smaller boilers are required
(plumbing considerations need to be
considered here due to differing flow/volume
characteristics through the large and small
boilers).

Example Systems:

Figure 4 Non-Mixed Boiler System

MB/MW 4:1

10.0 25:1 70%

1. Turndown: This is the ratio of minimum fire rate to

maximum fire rate: Example: a 20% minimum
modulation = 5:1 turndown (100%mod / 20% mod). A
(1) million BTU boiler = 200,000 BTUs minimum
input.

2. MOD MAX CLAMP: This value determines the

maximum modulation % at which the boilers will fire
to until all available boilers are firing.

3. Total System BTUs.

5.0 25:1 70%

3.0 25:1 70%

With the traditional Non-Mixed boiler system, the effective
turndown increases by the turndown ratio for every boiler
added. The min fire rate is equal to the minimum BTUs that
can be delivered to the system.

Page 14

SETUP & OPERATION HeatNet Control V3 1.x

Number of boilers * Turndown Ratio = Effective System
Turndown: 5 * 5:1 = 25:1.

Figure 5 Mixed Boiler System

System

MMBTU

4.2 35:1 60% KN6, KN6

3.8 42:1 70% KN4, KN4

2.2 55:1 81% KN2, KN2

3.6 90:1 72%

Effective

Turndown

MOD
MAX

Priority 1

5:1

KN2, KN2,

KN2

Priority 2

4:1

KN10, KN10,

KN10

KN10, KN10,

KN10

KN6, KN6,

KN6

KN10, KN10,

KN10

With the mixed boiler system, a lower minimum fire
rate/BTU can be delivered to the system by using small
boilers with larger boilers. This works in much the same
way as base loading.

Figure 6 KN Boiler Btu Chart (MBH)

the min inputs would then need to be divided by the sum of

Max Input of the Priority 1 boilers. The effect of this

the
would create a higher turndown. See: EXCEPTION NOTES:

Mod MAX % =

( ((Priority 1 Min) * (#Priority 1’s)) + Priority 2 Min)

Max Input of Priority 1 boiler * (#Priority 1’s)

Example: (2) KN6s, (2) KN20s
Redundancy: (120 + 400)/600 = 87%
No Redundancy: (120 * 2) + 400)/(600*2) =54%

KN2 KN4 KN6 KN10 KN16 KN20 KN26 KN30

Max Input

Min Input

Mod Max

80%

Mod Max

70%

Mod Max

60%

Mod Max

50%

200M 400M 600M 1MM 1.6MM 2MM 2.6MM 3MM

5:1

40M 80M 120M 200M 320M 400M 520M 600M

160M 320M 480M 800M 1.3MM 1.6MM 2.1MM 2.4MM

140M 280M 420M 700M 1.1MM 1.4MM 1.8MM 2.1MM

120M 240M 360M 600M 1MM 1.2MM 1.6MM 1.8MM

100M 200M 300M 500M 0.8MM 1MM 1.3MM 1.5MM

When selecting the Priority 1 boiler(s) for a high effective
system turndown, the BTU Min Input is selected first. (See:
KN Fusion & Boiler Btu Chart). Next, the MOD-MAX
value of this Priority 1 boiler needs to be greater than: Mod

MAX % =

(Priority 1 ‘s Min Input + Priority 2 ‘s M in Input)

Max Input of the Priority 1 boiler

The reason for this is keep the continuity of BTUs linear
without a BTU bump (discontinuity) when boilers are added
or shed. This is illustrated in the Boiler System Response 2
graph.

If redundancy is not required, the min inputs of the
Priority 1 boilers may be summed to lower the Mod Max %
value so smaller Priority 1 boilers can be used. The sum of

Page 15

SETUP & OPERATION HeatNet Control V3 1.x

EXCEPTION NOTES:

1. Mixing more than two different size/type boilers

becomes more complex than the scope of this manual
and is not recommended.

2. If using more than one Priority 1 boiler and the

calculated value is <

Priority 1Min * 2

Priority 1 Max Input

Use this result PLUS note 3 value as the
ModMax%.

3. Always add a few % (3-5%) to the calculated MOD

MAX % value to allow a guard band (tolerance).

4. If boilers are of different sizes, try to use larger

Priority 2 boilers.

If the calculated Mod MAX % value is greater
than 99%, the combination cannot be used
since short cycling will occur.

Once the Priority 1 and Priority 2 boilers are selected, they
can be multiplied in each Priority set to achieve the desired
system design BTUs. If the # of boilers becomes a large
number, a Priority 1 boiler with a higher Min Input may
need to be selected.

While considering the MOD-MAX value, the lower the
MOD-MAX the greater the combustion efficiency since it
effectively limits the input rate. The Typical Efficiency of
Non-Condensing Boilers chart can help illustrate how the
MOD-MAX value can affect the efficiency by limiting the
input until all boilers have fired. Non-condensing boiler
efficiency is relatively flat compared with condensing as
illustrated in the Typical Efficiency of Condensing Boiler
graph.

Figure 7 Typical efficiency of condensing boilers

(GAMA BTS2000 method)

In the Mixed Boiler System table (line 1), KN6s are set as

Priority 1 and KN10’s set as Priority 2. With a MOD MAX

of 60%, each KN6 can run to 360M (720M total) before a
KN10 is called ON (Add Delay timer set long enough).
Once both KN6s are running and the KN10 is then called on
and running, all (3) boilers will drop to a total of the 720M
BTUs: The sum of the KN6, KN6, and KN10. About 33%
modulation: (.33* 600M) + (.33* 600M) + (.33* 1MM) or:
198M +198M + 330M = 726M and operate at higher
combustion efficiencies. 33% is roughly between the top
two lines on the Typical Efficiency of Condensing Boilers
chart.

Figure 8 Boiler System Response 1

(2) KN2s, (3) KN6s

When running non condensing boilers at low

input rates, the risk of condensing should be
considered.

The Boiler System Response 1 chart illustrates how each

boiler (in the example) is brought on and fires to 60%, drops
to a lower fire rate and then adds the next boiler (vertical
dashed lines). Once all boilers are firing, the modulation is
released allowing all boilers to fire to 100%. So, for the first
2500 MBTH of load, the combustion efficiency is
maximized by running the boilers from low to middle input
rates.

Now if a (2) boiler system

(one of the KN6s & two KN20s

brought offline) using (1) KN6 with (1) KN20 and MOD­MAX set to 60%, the KN6 would fire to 360 MBTUs and

wait for the KN20 (Boiler System Response 2 graph). Once

the KN20 fired, the input rate would jump to 520 MBTUs,
400M (KN20 @ 20%) + the 120M (KN6 @ 20%). There
would be 160 MBTUS more than needed.

The PID algorithm would then compensate for the large
discontinuity (over fire bump) in BTUs and the KN20
would shut off (short cycle). This discontinuity is observed
in the graph below, (Boiler System Response 2) where the
jump from the KN6 @60% to the firing of the KN20 is
apparent.

Page 16

SETUP & OPERATION HeatNet Control V3 1.x

Figure 9 Boiler System Response 2

(1) KN6, (1) KN20, 60% Mod-Max

To correct this would require the KN6 to set the MOD­MAX to roughly 90% (Boiler System Response 3: not as
efficient as it could be) in order to have a linear BTU
transfer when the KN20 is added (fired).

Figure 10 Boiler System Response 3

(1) KN6, (1) KN20, 90% Mod-Max

Figure 11 Boiler System Response 4

(2) KN2s, (3) KN6s

The above Boiler System Response 4 graph illustrates
another system where 80% is used as the MOD-MAX
clamp.

In summary, the system should be tuned using the boiler
selection charts and the MOD-MAX value so that boilers
are brought on and fired in their respective efficiency curve
while maintaining continuity in BTUs. Since selecting the
Priority 1 boiler is integral to the fault tolerance of the
system, it is important to note any discontinuities in BTUs if
a Priority 1 boiler fails when multiple Priority 1 boilers are
used.

A KN6 running with a KN20 may not be an optimal choice

unless (2) KN6’s are always functional and used in the

Priority 1 set or (3) KN6s and one is allowed to be taken
offline.

A system employing this redundancy where (1) is allowed
to be taken offline is listed in the MIXED BOILER
SYSTEM chart. The example system uses (3) KN2s and (3)
KN10s. Two of the KN2s are treated as one when adding
the min inputs of the Priority 1 set.

Page 17

SETUP & OPERATION HeatNet Control V3 1.x

Mixed System Type 2:
Condensing / Non-Condensing

This mixed system may also have mixed boilers with
differing sizes as outlined in the Mixed System Type 1:
High System Turndown section. In the following examples
condensing high mass boilers will be used with non­condensing low mass boilers. The reason for creating a
mixed system is primarily to control the system cost.

ries water heaters will be

For the examples, the RBI FIII
used. These boilers are non-Condensing, fully modulating,
low mass, and HeatNet compatible. Also, consider the

Figure 13 Mixed Boilers: Example: Condensing/Non-Condensing

se

WESTCAST BOILERS series 28 with the HeatNet option
in the Priority 2 set.

Figure 12 Mixed Boiler System

System

MMBTU

3.45 28:01:00 62% KN6, KN6

4.2 35:01:00 76% KN6, KN6

2.3 29:01:00 62% KN4, KN4

Effective

Turndown

MOD

MAX

Priority 1

KN 5:1

Priority 2

MB/MW 3:1

FIII 750,

750, 750

FIII 1000,

1000, 1000

FIII 500,

500, 500

Figure 14 FIII Boiler Btu Chart (MBH)

MB/MW 500 750 1000 1250 1500 1750

Max Input

Min Input

3:1

Mod Max

80%

Mod Max

70%

Mod Max

60%

Mod Max

50%

500 750 1M 1.25M 1.5M 1.75M

166 250 333 416 500 583

400 600 800 1 1.2M 1.4M

350 525 700 875 1.1M 1.2M

300 450 600 750 900 1.1M

250 375 500 625 750 875M

Using the boiler charts and the examples used in: Mixed
System Type 1: High System Turndown, a mixed hybrid
boiler system can be designed. The Priority 1 boilers should
be setup so as to keep the non-condensing boilers from
seeing return water temperatures of less than 140F to ensure
a long heat exchanger life.

Since the FIII boiler is non-condensing the efficiency vs.
input is relatively flat. The MOD MAX value will not have
the same impact if t

he FIII non-condensing boilers were

placed in the Priority 1 set.

Page 18

SETUP & OPERATION HeatNet Control V3 1.x

Figure 15 KN Boiler Btu Chart (MBH)

Max

Input

Min

Input

5:1

Mod
Max
80%

Mod
Max
70%

Mod
Max
60%

Mod
Max
50%

KN2 KN4 KN6 KN10 KN16 KN20 KN26 KN30

200M 400M 600M 1MM 1.6MM 2MM 2.6MM 3MM

40M 80M 120M 200M 320M 400M 520M 600M

160M 320M 480M 800M 1.3MM 1.6MM 2.1MM 2.4MM

140M 280M 420M 700M 1.1MM 1.4MM 1.8MM 2.1MM

120M 240M 360M 600M 1MM 1.2MM 1.6MM 1.8MM

100M 200M 300M 500M 0.8MM 1MM 1.3MM 1.5MM

Page 19

CONTROL METHODS HeatNet Control V3 1.x

Base Loading, Relay Control

The control has the ability to control (1) base load boiler
using the K8 Relay contacts on J4 pins 2 & 6. In order to
connect to this plug, (2) wires with pins are required and
inserted in J4. Base Loading via relay requires these (2)
flying leads (loose wires available from the factory) to be
inserted into J4, pins 2 & 6. These (2) wires then make up
the Normally Open

contacts.
on Master or Member boilers. The solid state relay K8, with
contact connections on J4.2 & J4.6 has a rating of:

A

mp.

If the base load boiler is of the modulating type, a 4-20mA
signal is also provided on J4 pins 1 and 5. Jumper shunt JS1
will then need to be set to 4-20mA position. Two additional
wires (available from the factory) will need to be added to
the J4 pins at 1 & 5. Pin 1 is the + output of the 4-20mA

nsmitte

tra

r, and pin 5 is the – output. This modulating
control signal is used to modulate the base load boiler along
with the HeatNet boilers in parallel. The ADAPTIVE MOD
does not function in lowering the modulation rate when the
base load boiler is added. The PID will adapt to the newly
fired base load boiler and lower its modulation rate when
the increase in water temperature is observed.

This feature also can be used

0.1

to

1

Enable the base load feature by setting:

ADVANCED SETUP:SYSTEM:OPTION to BASE LOAD. This
setting the OPTION Relay to be used as control for a Base
Load Boiler.

1. ADVANCED SETUP:SYSTEM:OPTION to BASE LOAD.

This setting the OPTION Relay to be used as control
for a Base Load Boiler.

2. The ADVANCED SETUP:BASE LOAD BOILERS:

BASE LOAD BOILERS: to 1. Currently allows (1) base
load boiler.

3. The START & STOP qualifier condition to the method

discussed below.

4. The DELAY TIME to the amount of time required after

the start qualifier condition ha
boiler.

If a MINIMUM OFF time of the Base Load boiler is
needed, the Base Load boiler will share the MIN OFF TIME
of the boiler controlling it. If the base load boiler was
running and shuts off, the MIN OFF TIME will need to
expire before the boiler can start again. Once this time
expires, the DELAY TIME also needs to expire to start the
boiler. This will help in minimizing short cycle conditions
and can be set at: ADVANCED SETUP:FIRING MODE:
MODE:MIN OFF TIME.

s been met to start the

Figure 16 Base loading with KN boilers

Preferred:

A modulating base load boiler that can accept a 4-20mA
control signal such as the WESTCAST BOILERS 28 series
(and is preferred) or a non-modulating base load boiler that
is sized correctly to the H-Net boilers. The Westcast Boilers
28 series also has a HeatNet option. A 135 ohm input for
the base load boiler will need a converter from 4-20mA to
135ohm.

http ://www.westcastboilers.com

/

If the base load boiler is not of the modulating type,
stopping the Base Load boiler will require that the size of
the Base Load boiler in BTUs to be known relative to the
HeatNet boilers. Boiler selection is ideally; having more
total BTUs in the HeatNet boilers than total BTUs of the
Base Load boiler. This will prevent short cycling. Example:
(4) 2 million BTU HeatNet boilers = 8 million BTUs and
(1) 6 million BTU Base Load boiler.

When all (4) HeatNet boilers are running @ 95%, the Base
Load boiler is ca

lled on (de

mand is approx. 8 million
BTUs). As the Base load boiler comes on it introduces 6
million BTUs and the HeatNet boilers modulate down to
25% for a total output of 2 million BTUs and running at
high efficiency. The HeatNet boilers can now modulate to
the load from 1.6 million BTUs (20% mod) to another 8
million BTUs.

Page 20

CONTROL METHODS HeatNet Control V3 1.x

Not Preferred:

Example of having a larger Base Load boiler that is not of
the modulating type: If there is a 6 Million BTU Base Load
boiler running with (3) 2 million BTU HeatNet boilers, a
short cycling situation will arise when the (3) 2 million BTU
boilers are running @ 95% and the Base Load boiler is
called on. At this point there is a need for approximately 6
million BTUs. The (3) smaller boilers will then modulate
down to low fire. At this point, the (3) smaller boilers need
to shut off or the Base load boiler would need to shut off.

Figure 17 Base loading relay

1. First ensure that the ADVANCED
SETUP:SYSTEM:OPTION: is set to BASE
LOAD. The Base Load Relay (K8) will not be
enabled/used unless this is selected.

2. Now, The ADVANCED SETUP:BASE
LOAD:BASE LOAD BOILERS: must be set to 1.

3. When the START condition in the BASE
LOAD BOILERS menu is met, the K8 relay will
close. But, only when the DELAY TIME under
the BASE LOAD BOILERS menu expires.

24 VAC

There is no overlap. A selection for stopping the boiler now
needs to be determined. Setting the Stop qualifier;
Modulation to 40% or a low fire rate will shut the Base
Load boiler off and allow the (3) smaller boilers to modulate
up again (short cycle of the Base Load boiler; Use the Delay
Timer and Min OFF timer). The Stop qualifier; OA T >
xxF may also be used if the system design temperature is
known. Then let the Base Load boiler cycle off of its limits,
whether a 2 stage, Hi/Lo, or modulating boiler. The default
setting is for the Base Load boiler to stop first once the

water temperature exceeds the top of the heating band.

Base Load RIB Relay

Enable Input on

Base Load Boiler

24 VAC Return, or

Chassis Ground

Base Load Relay

Page 21

CONTROL METHODS HeatNet Control V3 1.x

Setting up base loading

The base load boiler is controlled using a set of contacts to
enable it (location J4). Enabling/Disabling this relay contact
can be done using any combination of (3) qualifiers to start
the boiler and (4) to stop the boiler. These qualifiers are:

1. Modulation %:
a. START menu item: The relay contact will close

when the MOD % from the Master boiler exceeds
this value. ADVANCE SETUP:BASE LOADING:

START>MOD

b.

STOP menu item

when the MOD % from the Master boiler falls
below this value. ADVANCE SETUP:BASE

LOADING: STOP<MOD

If the START>MOD value is set to a value

higher than the ADVANCED SETUP:MOD-
MAX: all boilers will be firing before this
modulation rate is reached. This will ensure
that all available boilers are firing before the
base load boiler relay is enabled.

c. Setting the : STOP<MOD to a % value slightly above

the min fire rate % of the system will ensure that
the base load boiler will stop before the first
condensing boiler stops. This is due to the
Modulation rate being close to the min modulation
rate before the water temperature exceeds the top

of the heating band.

2. Outside Air Temperature:
a. START menu item: The relay contact will close

to enable the boiler when the OA T read from the
Outside Air Temperature sensor (if Equipped) falls
below this temperature. ADVANCE SETUP:BASE

LOADING: START< OA T

b. STOP menu item: The relay contact will open to

disable the boiler when the OA T read from the
Outside Air Temperature sensor (if equipped) rises
above this value. ADVANCE SETUP:BASE

LOADING: STOP> OA T

If the OA T qualifier is used as the Start and

Stop qualifier, ensure that there is at least a
few degrees difference for hysteresis.

: The relay contact will open

3. Return Water Temperature

a.

4.

START menu item

close to enable the boiler when the RET read
from the Return Water Temperature sensor (if
Equipped) falls below this temperature.

ADVANCE SETUP:BASE LOADING: START>
RET

b.

STOP menu item

to disable the boiler when the RET
temperature read from the Return Water
Temperature sensor (if Equipped) rises above
this temperature. ADVANCE SETUP:BASE

LOADING: STOP< RET

:

FIRST

a.

STOP menu item

to disable the boiler when the temperature
exceeds the heating band. This gives the
result of stopping the Base Load boiler First.
Default setting.

: The relay contact will

: The relay contact will open

: The relay contact will open

Delay time

The DELAY TIME is also included to hold off starting the
boiler until the delay time is met. Once the start condition
qualifier term is met, the DELAY TIME will start counting
down. When the time expires, the base load relay contacts
will close. ADVANCE SETUP:BASE LOADING:DELAY
TIME. It is adjustable in a range of: 0 to 60 minutes.

Base Load Failsafe

If :

1) There are no boilers available to fire (offline or

faulted).

2) There are no boilers in local override.

3) There is a call for heat.

The J4 Base Load relay will close.

If a boiler becomes available and needs to fire, the Base
Load boiler will remain firing until the temperature exceeds
the band. This is provided to keep the system from entering
a no heat situation.

Page 22

CONTROL METHODS HeatNet Control V3 1.x

Short cycling may occur when a firing rate is

Heating Control Methods

An overview of the (5) methods for controlling the KN
series boiler are presented here. They are outlined in more
detail at the end of this section.

Heating Method 1

The first method is to use the KN Series boiler in its stand­alone modulating method. This method uses a PID
algorithm to maintain a setpoint and is enabled using the
HEAT DEMAND input. Closing a relay contact or switch
across the HEAT DEMAND input will cause the Master
boiler to control all member boilers using H-Net.

A member boiler may also be controlled by the HEAT
DEMAND input (LOCAL mode). The member boiler will
then ignore commands from the Master and maintain its
LOCAL SETPOINT at the supply sensor.

Operating Limit

When the master boiler or an external control input is used
to control a member boiler (i.e. AA, T1-T2, 4-20ma, H­Net), a software operating limit on the member boiler will
be used to limit the maximum output of the member boiler.
This operating limit can be adjusted in the
SETUP:SETPOINTS:OPERATING LIMIT.

sent to a member boiler that would cause the
supply temperature to raise high enough to
trip the operating limit (low flow rate). After
the supply temperature falls, the boiler would
restart and the process may continue. A
member boiler would use its supply (outlet)
sensor to protect itself from short cycling by
limiting the firing rate coming from the
Master. This occurs in the event that the

member’s supply temperature increases above

the (OPERATE LIMIT- OPERATE LIMIT
BAND).

Heating Method 2

The second method is to view the KN boiler as two separate
boilers or as a HIGH/LOW boiler using T1 & T2.

Heating Method 3

The third method is to allow a remote 4-20 ma or 0-10 VDC
signal to control the firing rate (modulation) of the boiler
using the 4-20ma input, along with the 4-20ma REMOTE
ENABLE input.

Heating Method 4

The fourth method turns the boiler ON and OFF @ 100%
modulation using the AA terminal.

Heating Method 5

The fifth method uses an RS485 digital communications
cable with the MODBUS protocol. The boiler is controlled
by writing and reading registers using MODBUS
commands. A bridge module may also be used to convert
BACnet or LonWorks protocols to MODBUS.

There is also an associated operating limit band that must be
set in conjunction with the operating limit to help prevent
this LIMIT from being reached. Its purpose, is to limit the
output of the boiler as it approaches the operating limit. If
the band is set to 10 degrees, then for every degree that it
approaches the operating limit, the maximum output will be
lessened by 10%. With a band of 20 degrees, for every
degree that it approaches the band, the maximum output will
be lessened by 5%. You can think of this operating limit as
a smart aquastat which prevents the High Limit from
tripping. This method minimizes boiler short cycling when
using external inputs. The minimum setting is 1 degree and
effectively turns the limit band OFF. The default setting is
20F.

Input Priorities

The KN-Series control inputs are prioritized so that

multiple levels of external control can be employed at the
same time. This means that if we are firing the boiler with a
low Priority input and a higher Priority input is called for,
the boiler will now fire at the higher Priority input. When
the high Priority input is removed, the boiler will revert

back to the lower Priority input that is still being called.

Priority 1

The AA terminal has absolute control, and if used, will
always fire the boiler at 100% output, regardless of any
other input. The 4-20mA input may be raised to this
Priority using ADVANCED SETUP: 4-20mA
INPUT:CHANNEL MODE:PRIORITY.

Page 23

CONTROL METHODS HeatNet Control V3 1.x

Priority 2

The HEAT DEMAND input is the next, and provides the
means to operate the boiler in LOCAL MODE when an
external control is not present, has failed, or needs to be
enabled or disabled. A member can override the H-Net
commands using this input.

Priority 3

If a HeatNet (H-Net) Network cable is connected between
boilers, and one is configured as a MASTER (requires
HEADER sensor), then the MEMBER boilers will be
controlled over the network by the MASTER.

Priority 4

The 4-20ma/0-10VDC input in tandem with the 4-20ma
REMOTE ENABLE input is next. Any signal over 4.02ma
or 2.01VDC will start and operate the boiler if the
REMOTE ENABLE is closed.

Priority 5

The lowest Priority is using the boiler as (2) stages
HIGH/LOW. These are the T1 and T2 inputs.

Figure 18 Heat demand input

MEMBER: Close to run at Local setpoint.
MASTER: Close to control all boilers and

run at System setpoint.

Master boiler

The MASTER boiler controls the system using a PID
algorithm. Once the boiler is started, a PID algorithm is
used to produce a modulation percentage value from 0­100%. This percentage is converted to a PWM, (P)ulse
(W)idth (M)odulation signal by each boiler. The
temperature of the water is maintained by sending this
PWM signal to the Variable Frequency Drive, which in turn
controls the blower motor. Since the main fuel valve is air­fuel coupled to the blower, the speed of the blower provides
the firing rate.

Each of these control methods will now be explained in
more detail:

Heating Method 1
HEAT DEMAND

Closing a relay contact, switch, or jumper across the HEAT
DEMAND input will enable this method. This method
allows operation as a setpoint control. As a setpoint control,
the Master (defined by having a common system supply
header sensor), on the H-Net network can command the
boiler fire rate of all Member boilers. The Master can call as
many boilers that it has available (boilers are auto-detected

over the H-Net cable by the Master) to meet its SYSTEM
SETPOINT. The H-Net cable must be connected and will

cause the amber light on the communications board to flash.
The amber light indicates an H-Net master is broadcasting
control information and a system heartbeat.

The AA terminal, the FAILSAFE mode active, 4-20ma at
PRIORITY:HIGHEST, and the HEAT DEMAND input
(LOCAL) on a Member, are the only inputs that will
override the H-Net control.

Member boiler(s)

A Member (lacking a common system supply header
sensor) boiler may also be controlled by the HEAT
DEMAND input (LOCAL mode). The member boiler will
then ignore commands from the Master and maintain its
own LOCAL SETPOINT at its supply sensor. This can be
viewed as a manual override on a member boiler. Be sure to
observe the use of the proper use of a Common System
Damper (See: AUXILIARY FUNCTION OPTIONS
section) and any system pumps or system common
interlocks.

Features of the HEAT DEMAND input include:

1. The control is designed to predict when to start and

stop the boiler and keep the setpoint in, or as close to
the control band as possible. If PREDICTIVE START
is enabled, the boiler may start when it is in the band
and not below it. This will help to maintain a more
accurate temperature relative to the setpoint. See also:
ADVANCED SETUP:FIRING MODE:PRDICTIVE
START: to disable this feature.

2. The control can also use the Outdoor Reset feature.

This feature allows the setpoint to be changed
automatically based on the outside air temperature. If
this feature is used, the control input: OR OVR
(OUTDOOR RESET OVERRIDE), can be used to
override the Outdoor Reset feature and run from the

local setpoint. A contact closure on the ‘AA’ input can

also override this method.

3. The 4-20ma setpoint control function works in

conjunction with this mode. This function translates a

Page 24

CONTROL METHODS HeatNet Control V3 1.x

4-20ma control signal to a setpoint mapped between
50F and 220F. These (2) temperatures are adjustable to
provide a setpoint range. The minimum start current is
also adjustable between 3.71 and 5ma. The setpoint
control feature is used in conjunction with the
REMOTE ENABLE input on J12A. This feature is
enabled in the SETPOINTS menu as:

SETPT SOURCE 4-20ma

4. There is also support for a common system damper,

Heat Exchanger support, and starting the Master first
for common venting. For an overview of each of the

menu settings see: DEFAULT SETTINGS section.

Heating Method 2
STAGE Control T1-T2

The boiler can also be operated in 2 separate stages using
the inputs T1 and T2 inputs. Its intended use is with an
external stage controller with no analog or modulation
outputs.

Closing only one of these contacts tells the boiler to operate
at MINIMUM FIRE.

1. Closing the other contact will fire the boiler at

MAXIMUM output (the same rate as closing the AA
input).

The AA, HEAT DEMAND (LOCAL) input, the H-Net, the
4-20ma input will all override the stage control inputs.

Heating Method 3
4-20ma Control

Placing a current source between the + and – 4-20ma inputs

will allow remote control of the boilers firing rate. An
adjustable starting mA current signal here will start and then

fire the boiler at the minimum fire rate. See: ADVANCED
SETUP:4-20mA INPUT: CHANNEL MODE.

See section OPTIONAL FEATURES Using the 4-20ma

input for extensive detail.

A 20ma signal will fire the boiler at the maximum firing
rate. The input current signal is viewed as a percentage to
the boiler from 0 to 100% (0-20mA). This means that a
20% (4mA) input signal is required to start the boiler, but
since the boiler is classified as having example:4:1 turn
down ratio, the boiler can only be fired as low as 25% of
output. Any signal between 20% and 25 %, will fire the
boiler at the minimum fire rate. If the MINIMUM setting of
the boiler is set above the example: 4:1 turndown of 25%
(such as 33%), a control signal change between 25% and
33% will not change the boilers firing rate. Once the control
signal rises above the MINIMUM fire rate, the control
signal will then affect control of the boilers fire rate.

Figure 19 Stage control input

The maximum output of the boiler is based on

the MAX VFD setting in the calibration mode
and not the nameplate rating.

The AA terminal, the HEAT DEMAND, and the H-Net
NETWORK are the only inputs that will override the 4­20ma input.

Heating Method 4
AA Input

HIGH FIRE input Control: The AA input will fire the boiler
at HIGH fire (maximum output of the boiler). No other
inputs can override this input.

Figure 20 AA — High fire input

Method 2

Stage Control Inputs:

T1 & T2

Method 4: Close this AA contact

to run the boiler at High Fire.

Page 25

CONTROL METHODS HeatNet Control V3 1.x

Heating Method 5
MODBUS communications

The fifth method uses an RS485 digital communications
cable with the MODBUS protocol to control the boiler
using the H-Net network. The Boiler or Boiler network will
run as in Method 1, but instead of the HEAT DEMAND
input, a software form of the HEAT DEMAND input is
used (40001: Boiler/System Enable/Disable). See:
MODBUS COMMUNICATIONS section.

Figure 21 MODBUS connections

Modbus Using

RJ45 Cat 5 cable

Building

Management

Modbus Using

shielded 3 wire.

Protocessor option

An optional BACnet or LonWorks bridge module can be
used to connect the MODBUS network to a BACnet or
LonWorks network.

Figure 22 Protocessor bridge module option

The System Setpoint Timer also needs to be loaded
periodically to allow the H-Net system to fallback to
Method 1 in the event communications is lost from the
Building Management System (BMS). The MODBUS
protocol allows writing and reading registers using
MODBUS commands.

This method allows enabling and disabling the boiler or H­Net system, changing setpoints, reading boiler(s) status, or
temperatures remotely using digital commands. See the

section: MODBUS Communications.

Page 26

OPTIONAL FEATURES HeatNet Control V3 1.x

Figure 24 4–20ma enable connection

Using the 4-20ma input (OPTIONAL)

The 4-20ma input is designed to operate per the ISA-50.1
standard. It will support Type 2, Type 3, and Type 4
Transmitter/Receiver circuits.

The Type 2 and Type 3 circuit may use the supplied +24VDC
and 24VDC RET connections (J10B) to power a remote

transmitter. The –ma terminal will need to have a jumper

connected to the adjacent 24VDC RET terminal to reference
the signal ground.

With the type 4 configuration, multiple boilers (up to 5), may

be connected in series using the –ma +ma –ma +ma scheme

(no jumper to 24VDC RET). This allows one 4-20ma
transmitter to control multiple boilers. A free-floating 250

ohm resistor is viewed by the BMS (or external control’s) 4­20ma transmitter across the + and –4-20ma terminals with

this method.

Figure 23 4–20ma connections

24 VDC Return

(-)

4-20mA/0-10VDC

(+)

Channel 1:

Channel 2:

4-20mA/0-10VDC

(+)

(-)

24 VDC

Closing this contact enables

the 4-20mA/0-10VDC input

The 4-20 ma input uses a 250 ohm sense resistor to convert
the current to a voltage from 1 to 5 volts DC for the control to
use. For this reason, a 1-5 VDC control voltage may also be
used across the 4-20mA +/- input, but it still needs to supply
the necessary current, i.e. 20mA. This resistor is located on
the bottom side of the control board. When a 4.02 ma signal is
sensed, the boiler will initiate a start sequence and fire the
boiler at its minimum setting if the REMOTE ENABLE input
is closed. This is typically 25% of the boilers output (4:1
turndown).

If the dip switch S6 is set to the 0-10 position (UP) See:
Figure 31, the 4-20mA input will accept a 0-10 VDC signal.
The channel will also need to be setup in the menu:
ADVANCED SETUP:4-20ma INPUT:CHANNEL MODE. The
operating range will be from 2-10 VDC or twice what was

previously stated for the 1-5 VDC functionality. To convert a
0-10VDC signal to mA, divide by 2510 (ohms).

NOTE: Due to the inability of control voltage methods (1-5,
2-10 VDC) to reject noise and compensate for line loss, the
use of the 4-20mA control current is recommended. The
control voltage methods may be less expensive, but are the
least stable. If using a 0-10VDC control signal, a source
current of 5mA is required.

If using a remote panel with a relay and a 4-20 ma transmitter
for operation, connect the 4-20ma transmitter output from the
remote panel to the member boilers using the floating 250
ohm method (type 4). The relay contacts on the remote panel
will then be connected to the associated 4-20ma REMOTE
ENABLE inputs on the associated boiler(s).

Page 27

OPTIONAL FEATURES HeatNet Control V3 1.x

For non Ametek blowers, the minimum setting

of the boiler is calibrated so that the minimum
PWM signal to control the Blower motor is
20%. The VFD to blower motor operates with a
control signal from 20% - 80% Pulse Width
Modulation. This PWM signal to the VFD can

be measured using a multimeter. It is a 0–

10volt square wave signal at 110 Hertz. A 20%
modulation signal will read 2.0 VDC, and an
80% modulation signal will read 8.0 VDC on
an RMS multimeter. See Figure 37, page 47.

For Ametek Blowers, the minimum signal to

control the blower will be less than 20%, but
the display % will be equal to the turndown %
of the boiler. Also, the signal sent to the
Ametek blower is twice that of non Ametek
blowers, so the VDC reading will need to be
divided by (2) to get the modulation % sent to
the Blower. The Ametek blower also has a

menu located at: ADVANCED
SETUP:BLOWER SETTINGS. This menu

allows the Acceleration, Deceleration, and Soft
Start Values to be set for proper operation of
the Blower.

Setpoint Control functionality can be implemented remotely

using the 4-20mA input. This function translates a 4 to 20ma
control signal to a setpoint mapped from 50F to 220F. The

feature is enabled in the SETPOINTS menu as: SETUP:
SETPOINTS:SETPT SOURCE 4-20ma.

SETPOINT 220F for backwards compatibility with the older
version. NOTE: anytime a new firmware version is uploaded
to the control, these values return these defaults.

Anytime a new firmware version is uploaded to

the control, these values return to these
defaults.

If using the direct modulation mode by applying a 4-20ma
current, only the BOILER START x.xx setting applies.

The 4-20 mA input can be set to HIGH PRIORITY. This is

done in menu: ADVANCED SETUP:4-20mA
INPUT:CHANNEL MODE. This allows a member boiler to

be taken offline and directly modulated by an external control.
If the Master is using it for heating and the 4-20mA is set to
HIGH PRIORITY, an external control can now output a 4-

20mA signal which will take over the boiler’s fire rate. This is

typically used for DHW control.

ADVANCED SETUP:4-20ma INPUT:CHANNEL M O DE.

Also, when selecting; SETUP:SETPOINTS:SETPT SOURCE
and selecting 4-20ma, the 4-20ma INPUT menu will be
automatically entered.

You may now select the current at which the boiler will start.
It is adjustable from 3.7ma to 5ma. Hysteresis of .1ma is
always in effect. So, if the starting ma = 4.10ma the boiler
will start when the control current applied achieves this value
of 4.10ma. The boiler must drop .1ma below this to turn OFF,
in this example 4.00ma. This hysteresis value is not
adjustable.

When using the 4-20ma setpoint control, a band may now be
set at which the 4-20ma signal will operate over. The lower
setpoint is defined as 4ma SETPOINT and the upper setpoint
is defined as 20ma SETPOINT. The 4ma SETPOINT is
linked to the BOILER START x.xxma where this starting
current is the lower setpoint. So, if we set the 4ma
SETPOINT to 130F and the 20ma SETPOINT at 180F we
will have established the band. Once a starting control current
of BOILER START 4.1mA is applied, and the 4-20
REMOTE ENABLE INPUT is closed, the boiler will start and
the setpoint will be set to 130F. If a control current of 10ma is
applied the boiler will track on a linear slope towards the
20ma SETPOINT settling at a SETPOINT of ~149F. As the
current increases to 20ma, the SETPOINT will indicate 180F.
The Default setting is 4ma SETPOINT: 50F, and 20ma

Page 28

OPTIONAL FEATURES HeatNet Control V3 1.x

Figure 26 Local & DHW Pump connections

Circulator Pump Options

There are provisions for a system pump(s) and a local pump.
This is to allow for primary/secondary loop configurations.
The system circulator pump is implemented using the K4,
K13 RELAY and normally open contacts at J13 SYSTEM
PUMP 1 and SYSTEM PUMP 2.

The pumps require motor contactors to isolate

the on-board relay contacts. The on-board
relays should never be used to energize large

pumps directly. Figure 25 illustrates the

connections without contactors for illustrative
purpose.

Figure 25 System Pump connections

System Flow

Prove Switch

System

Pump 1

System

Pump 2

K4

K13

Local Pump/Valve
Normally Closed &

Normally Open Contacts

DHW

Normally Closed &

Normally Open Contacts

The system circulator pump is supported by (2) modes and

special features.

1. The first mode will allow the circulator pump to remain

on, unless the control’s outside high air temperature

setting has been met when using OUTDOOR AIR
RESET.

2. The second mode will allow the circulator pump to be

turned on whenever there is a call for heat (any control
input). This mode will stop the circulator pump when the
call for heat is lost and the pump post purge time has
been satisfied.

The summer pump jog is a special feature that can be selected
when the system is in summer shutdown (OUTDOOR
RESET). The jog allows the system circulator pump(s) and
the local pump to run for the system pump purge time once a
week. It can be set to any day of the week and will occur at
12:01 AM. If (2) system pumps are present, and after the first
pump finishes its post purge, the second one will start and the
first one will stop.

The system flow proving switch is implemented using
SPARE 3/System Water Flow on J11A. If a flow switch is
connected to the WTR FLW interlock, the HeatNet control
will wait up to 10 seconds to prove flow. If flow is interrupted
after it has been established, an error will be displayed and the
boiler will cycle OFF. As long as there is a call for heat,
every 10 minutes the circulator pump will try to re-establish
flow and start the boiler again.

When (2) system pumps are present and flow is not
established or is lost (2) things will occur to try and keep heat
in the system.

1. When first starting a system: If after a 10 second

wait to establish flow has failed, the first pump will
change to the second pump. The second pump will now
try to establish flow for 10 more seconds. If the second
pump fails to establish flow, the HeatNet control waits

10 minutes. After the 10 minutes has expired, the

control now starts with the second pump and attempts
to prove flow for 10 more seconds. If flow does not

Page 29

OPTIONAL FEATURES HeatNet Control V3 1.x

prove, the control changes to the first pump and
attempts to prove flow. This cycle will continue

indefinitely until flow is established. If flow is lost
while running: this process is also used in an attempt

to re-establish flow.

2. If PUMP ROTATION is set to PMP HRS the PUMP

ROTATION will be temporarily set to SYS HRS. This
is to prevent re-starting the failed pump due to its
runtime hours. Setting the PUMP ROTATION to SYS
HRS will allow a retry of the failed pump after the
rotation hours has expired. Power cycling of the boiler
or using the PUMP ROTATION menu will revert back
to PUMP ROTATION = PMP HRS if this was the
original setting.

For system pump modulation a 0-10Vdc control signal

output is provided at J4.3 (signal) and J4.7 (ground). This
signal is output by the Master boiler as a percent function of
the number of boilers running and can be used to set the speed
of a System Pump using a Variable Frequency Drive. Two
wires are required and need to be inserted into the J4.3 and
J4.7 positions to access this signal.

Note: This signal has a step response and is not linear to the
system or boiler’s input firing rate.

The output signal is proportionally mapped to % using the
equation:

If (2) pumps are available, pump rotation is available. The
rotation of the (2) pumps can be controlled using two
methods.

3. Pumps are switched based on the system run time

4. Pumps are switched by the difference between each

pump’s runtime. The HeatNet control keeps a
running record of each pump’s runtime in hours. If

a pump is taken offline or replaced. The runtimes
can then be adjusted until they become equal.

These features may be selected in the menu, SETUP:PUMP
OPTIONS:SYSTEM PUMP:PUMP ROTATION

The local circulator pump is supported by (3) modes and (2)

features.

1. The first mode allows the circulator pump to remain on,

unless the control’s outside high air temperature setting

has been met when using Warm Weather Shutdown.

2. The second mode will allow the circulator pump to be

turned on whenever there is a call for heat (any control
input). This mode will stop the circulator pump when the
call for heat is lost and the pump post purge time has
been satisfied.

%VFD = (boilers running/total boilers)

The %VFD represents the stepped percentage of boilers
running where:

0Vdc = 0% (to) 10Vdc = 100%

If there are (6) boilers in a system and (2) are running, the
control signal = 33% or 3.3Vdc. This signal could then be

applied to a system pump’s VFD to control the speed of the

pump relative to how many boilers are firing. The VFD would
need to be set appropriately to allow the correct flow through
each boiler.

In low volume systems sudden temperature changes may
occur when the flow is stepped up or down by a large
percentage. In these situations the ADAPTIVE MOD may
need to be disabled and the ORIGINAL KN method used.
Other adjustments may also be required.

Currently, no failsafe mode is available in the event the

Master boiler’s control fails. If this method is employed, a

failsafe boiler could be used to override the control signal and

enable the system pump’s VFD using some external wiring

and an external relay, or have the VFD default to a safe speed
on loss of the control signal.

3. The third mode works much the same as mode 2, but it

allows the inlet sensor (RETURN) to be used with the
outlet sensor (SUPPLY) to keep the pump on until a delta
(difference) temperature is met. A return temperature
sensor is required for this mode, because the delta

temperature (SUPPLY – RETURN) measured is across

the boiler. In this mode, the post purge time is also used.
After the delta temp has been met, the post purge time
needs to expire before the pump is turned off. This mode
works much the same as mode 2.

PUMP/VALVE OPTION: This is a special feature of the

local circulator pump to prevent deadheading water flow
when all boilers are off. When this feature is enabled, the
master boiler will enable its local circulator pump/valve when

NO boilers are running. If boilers are running in LOCAL

override and not controlled by H-NET, but are visible to H­NET, the pump(s) on these boilers are presumed ON. In this

situation, the master will not enable its circulator pump/valve

unless it is running.

Another feature of the PUMP/VALVE OPTION is to control
a local (primary) pump using a Variable Frequency Drive.
This feature may be required when a secondary system pump

is also variable speed. To enable this feature: SETUP:PUMP

OPTIONS:LOCAL PUMP PUMP/VALVE
OPTION:LOCAL PUMP VFD: ON. Setting this Option to

ON will map the control signal on J4 pins 1+ and 5- to the
modulation rate. (2) wires need to be run from J4.1+ and J4.5-

Page 30

OPTIONAL FEATURES HeatNet Control V3 1.x

to the VFD’s input connection. Ensure that the JS1 shunt

jumper on the control board is in position 0-10 or 4-20mA as
required.

Auxiliary Function Options

Relay K5 and the terminal J13 DAMPER is used to control a
combustion air damper. J12B.7 & .8 are used to detect the dry
contact proof switch from the damper. A proof time of up to 4
minutes can be set before the boiler can start or an alarm
condition will occur. The Combustion Damper can be setup in

the SETUP:AUX FUNCTIONS menu.

Using the LINKED/COMMON setting, the Master boiler
controls a system damper, so in the event this damper fails to

open, the system will not start. If the Master boiler’s system

damper fails, then no call for heat will be made to the member
boiler(s).

Using the INDEPENDENT setting, each member boiler can
control its own damper and is independent of the Master
boiler when a call for heat is made to the member. This allows
for separate dampers for each boiler. They can be wired to
J12B terminals 7 and 8.

If a common system damper is used (controlled by the Master
boiler), each individual boiler must prove that the combustion
air damper is open when it is placed in LOCAL. This may be
done using J12B terminal 7 on all boilers wired to the

damper’s prove switch. Terminal 7 is the sense input and

terminal 8 is 24 VAC. Connecting a wire to terminal 8 is not
recommended.

See Figure 38, Common system damper wiring, Page 48.

A separate/independent 24 VAC source is

recommended to be used for the damper prove
switch when a common system damper is used.
If you use terminal 8 to supply power from the
Master and the Master is powered OFF, no
boiler will be allowed to fire due to the loss of
power through the prove switch. A backup
boiler will also need to have the damper relay
contacts wired in parallel with the Master for
when the Master is powered OFF.

A second wire on the Master J12B terminal 7 is then
connected. The other end of this wire is then run to the first
Member boiler J12B terminal 7. If another member boiler is
present, a second wire can be connected to the first member
boiler J12B terminal 7 and the other end connected to the
other boiler J12 terminal 7. This method can be continued if
additional boilers are present. This input must be selected in

the SETUP:AUX FUNCTIONS:COMBUST AIR
DAMPER menu.

Page 31

OPTIONAL FEATURES HeatNet Control V3 1.x

WATER TEMP

LOW OA TEMP

180 °F

10 °F

Water temp @
outside air temp

WATER TEMP

HIGH OA TEMP

140 °F

70 °F

Water temp @
outside air temp

Outside air temperature
where Warm Weather
Shutdown occurs

WARM WEATHER SD=ON

If set to ON here

Water Temp

when a contact is closed across this input. This can be used as

Outdoor Reset

a Domestic Hot Water demand input.

The Outdoor reset feature allows the water setpoint
temperature to change dynamically with the outside air
temperature. It also provides an adjustable temperature that
shuts the boiler (or boiler system) down when the outside
temperature rises above it.

Figure 27 Outdoor reset curve, typical

WATER TEMPERATURE SETPOINT

190
180
170
160
150
140
130

10 70

Another function of the OUTDOOR RESET is the
Winter/Summer mode ( (W)arm (W)eather (S)hutdown).
With the WWS SETPOINT set to 72F and WARM
WEATHER SD set to ON, the boiler/system will enter
summer shutdown when the Outside Air temperature rises
above 72F. While in this state, the OR OVR input on J12A
can be used to bring the boiler/system on to maintain the
water setpoint at the LOCAL or SYSTEM SETPOINT value.

During WWS operation, the System pump will not be enabled
just the Local pump unless the SETUP:SYSTEM
PUMP:OVR ENAB IN WWS is set to ON. This is the System
Pump Priority mode. When SETUP:SYSTEM PUMP:OVR
ENAB IN WWS is set to OFF, the system pump will not
come on while in WWS with the OR OVR override input
closed.

Sensors

The H-Net control supports a standard 10K thermistor (Type
ACI/10K-CP). These sensors can be calibrated to the control
by entering the sensor menu and placing a precision 10k
resistor on an input.

Outside Temp

The above chart shows how the water temperature setpoint
changes with the Outside air temperature. The four values of
180, 10 and 140, 70 are the default values:

WWS Setpoint 72 °F

The chart depicts what the water temperature setpoint will
equal with a corresponding outside air temperature. At an
outside temperature of 10F and below, the water temperature
setpoint will be limited to 180F. With an outdoor temperature
of 70F and above, the water temperature will be limited to
140F. The water temperature setpoint will track along the
charts plotted line with corresponding outside temperatures.

The OR OVR (Outdoor Reset Override) input on J12A can be
used to override this Outside Air Setpoint and maintain the
water setpoint at the LOCAL or SYSTEM SETPOINT value

Immersion sensors must have wells.

Security

A password can be used to lock out control and setup features.
It can be enabled, but is shipped in the disabled state.

Diagnostics

The H-Net control can display and identify faults in a
meaningful way. If an interlock trips, it will be indicated in
the main screen display, along with an audible alarm
(mounted on control board) and a set of relay contacts will
close. A record of this, with a time stamp, will also be entered
into the log as an aide in the diagnosis of the event. The log
can be downloaded and a histogram used to display the data.
If using Modbus, BACnet, or LonWorks, there are software
flag bits in registers available.

Open and shorted sensors are checked continuously, so that in
the event of a sensor failure, the system shuts down and the
alarm relay is closed.

Page 32

OPTIONAL FEATURES HeatNet Control V3 1.x

If a pump fails (flow switch required), or the flow switch
fails, the boiler will cycle the start condition every 10 minutes
in an attempt get the boiler restarted.

If the damper fails to open and never closes its proof switch, a
retry algorithm will attempt a retry. Every 10 minutes the
damper relay will cycle and try to open the damper again.

If the H-Net control closes the last interlock string connected
to the ignition control and the ignition control never closes its
Blower Relay, the H-Net control will wait 2 minutes. The H­Net control will then retry for the duration of the local pump
post purge time and then retry the ignition sequence. During

this time “retry strt” will be displayed in the status screen.

After (5) attempts the H-Net control will lock out and display
call service.

Communications

The H-Net control has the ability to communicate using the
MODBUS protocol with a building management system.
Most registers and functions are available for MODBUS
access. Access is allowed using the RS485 MODBUS PORT
connecter on the communication board. Version 2.x Control
has these connections integrated on the main board.

An optional BACNet or LonWorks bridge module can be
used to connect the MODBUS network to a BACnet or

LonWorks network. See Method 5 control.

3. The Failsafe boiler must have the LOCAL SETPOINT

set to the same setpoint temperature as the Master

boiler’s SYSTEM SETPOINT.

Be aware that the boiler may start without a call-for-heat in
the FAILSAFE MODES. FAILSAFE MODES can be
accessed through the:

SETUP:AUX FUNCTIONS:FAILSAFE MODES.

The following are types of Failsafe conditions.

1. Building Management System Failure

If a BMS system is controlling the setpoint and enabling
the boiler system, a timer is provided to allow operation
of the system in the event that communications are lost
with the BMS system. The HeatNet boiler system will
run locally if communications is lost and this timer
expires due to the lack of being updated.

The system setpoint timer and system setpoint work in
tandem to externally control (i.e. a BMS - building
management system) the operating setpoint. The setpoint
(countdown) timer should be loaded with a timeout value
(in seconds) prior to writing the system setpoint. When
the timer reaches zero, the control assumes that the BMS
is no longer operating and the local setpoint (saved on the
control) is reloaded. If the setpoint timer is not written, a
default timeout value of 60 seconds is assumed. The
timer is automatically reloaded with the default value
when a setpoint is written.

Failsafe Modes

FAILSAFE MODES have been added to help protect systems
from loss of heat conditions. When using one of these modes

ensure that you connect any DAMPER control, or system
pump control to safely allow operation with the assumption

that the MASTER boiler or BMS system is DOWN.

FAILSAFE REQUIREMENTS:

1. Since the Member boiler that will be assigned the

Failsafe duty will always turn the system pump ON, this
boiler should not be used for DHW heating. If the Master
controls the system pump, then the Failsafe Member
boiler would need to control the system pump in parallel
with the Master boiler. Wire the System Pump contacts in
parallel with the Master.

2. If the combustion air damper is used as a common system

damper, the Failsafe boiler should be wired to control the
damper in parallel with the Master boiler.

The BMS mode is always on and no menu item

is available.

2. HeatNet Communications Lost

SETUP:AUX FUNCTIONS:FAILSAFE MODES:H-NET
COMM LOST:

This mode allows a member boiler to run in LOCAL if
the communications link via the H-NET cable is lost.
This includes the MASTER boiler losing its Control
board, Communications board, or the power on the
MASTER is switched OFF. When this MODE is set to

ON, and if the member boiler loses it’s link (heartbeat

packet over the H-NET cable) to the MASTER Boiler,
this MEMBER will fire to the LOCAL setpoint.

The heartbeat packet over the H-NET cable

needs to be lost for 10 minutes.

This MEMBER boiler will continue to run at the LOCAL
setpoint until H-NET communications from the
MASTER boiler is re-established.

Ensure that this Member boiler’s Damper and System

pump control are configured correctly with the

Page 33

OPTIONAL FEATURES HeatNet Control V3 1.x

assumption that the Master is not powered. Also ensure
that any other System settings related to outside air
temperature sensing and system interlocks are set to
provide safe operation.

3. Low Temperature Protection

LOW TEMP: OFF, SUPPLY, HEADER, DHW, or
RETURN

This mode may be used by the MASTER or MEMBER
boiler and can be used as a type of freeze protection. In
this mode you may select which Sensor you wish to
monitor, or you may opt to turn this mode OFF. If you
select a sensor, you may then associate it with a
temperature at which the boiler will turn ON. Once the
temperature at this sensor falls below the LOW TEMP
temperature the boiler will start and fire to its LOCAL

setpoint. Once the Boiler reaches it’s setpoint it will turn

OFF.

4. Using the Base Load Relay

If there are no boilers available to fire (offline or faulted)
and there are no boilers in local override, and there is a
call for heat, The J4 Base Load relay will close. If a
boiler becomes available and needs to fire, the Base Load
boiler will remain firing until the temperature exceeds the
band. This is provided to keep the system from entering a
no heat situation.

Page 34

OPTIONAL FEATURES HeatNet Control V3 1.x

Domestic Hot Water Methods

Domestic Hot Water control is supported using (4) methods.
When using the Domestic Hot Water methods, the wire
jumper, JPS1 on each control board providing Domestic Hot

Water, must be cut to limit the boiler’s maximum output

temperature of 200F. Refer to Figure 42 for control input and
output locations.

Figure 28 Jumper JPS1

The following Domestic Hot Water setup information will
include a walkthrough using the menus.

DHW METHOD 1: DHW Tank Sensor
Input

DHW METHOD 1a: DHW Heating ONLY using a
Single Boiler or a DHW MASTER and Member
boiler(s) employing H-Net

This method utilizes a 10k thermistor connected to the DHW
Sensor input of a DHW MASTER, or a stand-alone boiler,
and a DHW tank WITHOUT a HEADER sensor. It requires a
DHW setpoint and other parameters to be set. This method is
used when the water temperature in the tank needs to be no
greater than the setpoint, with little overshoot of temperature.
One of its limitations is that it may short cycle. It functions
much in the same way a tank thermostat works.

This method works with (2) settings. A target tank water
setpoint (DHW SETPOINT) and a start/add boiler
temperature setting (DHW DIFF). Boilers are started as long

as the tank’s water temperature is below the (DHW

SETPOINT – DHW DIFF). The first boiler is started

immediately. The next boiler(s) is started after the ADD
BOILER DELAY time expires. Boilers are not added when

the temperature is above the (DHW SETPOINT – DHW

DIFF) and below the DHW SETPOINT. Once the DHW
SETPOINT is reached all boilers shut off. This limits the tank
temperature to the setpoint + post purge time of the DHW
pump.

Setting up this method is done via the menus in:

SETUP:DOMESTIC HOT WATER.

1. Connect a 10k thermistor from the DHW tank’s

sensor well to J10B terminals 1 & 2 on the DHW
MASTER, or stand-alone boiler. Wire any pump
or valve from the DHW Pump relay (normally
open) contact to control flow of the heating water

into the tank’s coil.

2. Next, enter the DOMESTIC HOT WATER menu.

When prompted for DHW BOILER?, enter NO.
We will enter YES when we are finished entering

all parameters

3. Change the DHW SETPOINT to the desired target

temperature of the water in the tank. Once the
control determines there is a call for DHW, the
DHW SETPOINT is loaded and the Master boiler
will target this new setpoint.

4. Now, change the DHW DIFF to the desired

differential. This setting corresponds to the
minimum water temperature required in the tank.
DHW heating will be initiated when the DHW

tank’s water temperature is below the DHW
SETPOINT – DHW DIFF.

5. How long the temperature of the tank stays below

the (DHW SETPOINT – DHW DIFF) is used to

determine when boilers are started along with the
ADD BOILER DELAY.

6. Scroll down to USE SENSOR? Press the

SELECT key and select YES, then press the
SELECT key again

control the tank temperature using its sensor.

7. Press the DOWN arrow key again to position the

cursor beside the menu item DHW PRIORITY?.
Setting this value to YES will turn OFF the
system pump when the DHW mode is active.
Setting this value to NO leaves the system pump
on.

8. Press the DOWN arrow again and the menu item

POST PURGE should appear. This is the time that
the DHW pump relay remains energized after the
DHW SETPOINT has been satisfied. Once the
tank has reached setpoint all boilers will shut off.
Using the POST PURGE time to dump the

boiler’s heat into the tank may heat the tank

above the setpoint temperature. Care should be
taken here.

9. Press the DOWN arrow again and the menu item:

DHW MASTER?, will be displayed. If this item is

. This will allow the boiler to

Page 35

OPTIONAL FEATURES HeatNet Control V3 1.x

set to YES, once the DHW MASTER receives a

HEAT DEMAND signal, it will call other boilers

it has available using H-Net. Setting to NO,

requires no Heat Demand signal, and will only
enable the single boiler when the DHW Tank

Temperature drops below (DHW SETPOINT –

DHW DIFF).

NOTE: DHW MASTER? YES is to be only be

used WITHOUT a Header Sensor.

10. Finally, go to DHW BOILER?. Select YES. If

JPS1 has not been cut, a message will appear
instructing to do so. Once this is done, the stand
alone boiler will control the temperature in the
tank, or the DHW Master will control the
temperature in the tank using as many boilers as
it has available on H-Net.

NOTE: DHW BOILER? Does not need to be
set to YES on MEMBER boilers, only the DHW

MASTER or on a stand alone boiler providing
DHW.

NOTE: JPS1 MUST be cut on all boilers

providing DHW.

DHW SETPOINT is loaded and the Master boiler
will target this new setpoint.

4. Now, change the DHW DIFF to the desired

differential. This setting corresponds to the
minimum water temperature required in the tank.
DHW heating will be initiated when the DHW

tank’s water temperature is below the DHW
SETPOINT – DHW DIFF.

5. Since the same the ADD BOILER DELAY time is

used for space heating and DHW, how long the
temperature of the tank stays below the (DHW

SETPOINT – DHW DIFF) has to be considered
when setting the ADD BOILER DELAY.

6. Scroll down to USE SENSOR? Press the

SELECT key and select YES, then press the
SELECT key again. This will allow the boiler to

control the tank temperature using its sensor.

7. Press the DOWN arrow key again to position the

cursor beside the menu item DHW PRIORITY?.
Setting this value to YES will turn OFF the
system pump when the DHW mode is active.
Setting this value to NO leaves the system pump
on.

DHW METHOD 1b: Combo DHW and Space
Heating using a MASTER Boiler and Member
boiler(s) employing H-Net

This method utilizes a 10k thermistor connected to the DHW
Sensor input of a MASTER boiler, a DHW tank AND a
HEADER sensor. This Method works the same as DHW
METHOD 1a, but also has the ability to provide space
heating.

Setting up the DHW portion of this method is done via the

menus in: SETUP:DOMESTIC HOT WATER. For information

on setting up the space heating portion of the method Refer to

Heat Demand Control Method 1 located in the CONTROL

METHODS section on page 22.

1. Connect a 10k thermistor from the DHW tank’s

sensor well to J10B terminals 1 & 2 on the
MASTER, and connect a Header Sensor to the
SYSTEM HEADER input. Wire any pump or
valve from the DHW Pump relay (normally open)
contact to control flow of the heating water into

the tank’s coil.

2. Next, enter the DOMESTIC HOT WATER menu.
When prompted for DHW BOILER?, enter NO.
We will enter YES when we are finished entering

all parameters

3. Change the DHW SETPOINT to the desired target

temperature of the water in the tank. Once the
control determines there is a call for DHW, the

8. Press the DOWN arrow again and the menu item

POST PURGE should appear. This is the time that
the DHW pump relay remains energized after the
DHW SETPOINT has been satisfied. If there is
no HEAT DEMAND signal, once the tank has
reached setpoint all boilers will shut off, and the
post purge time will begin. If there is a HEAT
DEMAND Signal when the tank has reached
setpoint, the boilers will continue running to
provide space heating, and the DHW pump relay
will be de-energized immediately. Using the

POST PURGE time to dump the boiler’s heat into

the tank may heat the tank above the setpoint
temperature. Care should be taken here.

9. Press the DOWN arrow again and the menu item:

DHW MASTER?, will be displayed. Set it to NO for

this DHW Method.

NOTE: This DHW Method requires no Heat

Demand signal to control the temperature in the
tank. As soon as the DHW Tank Temperature

drops below (DHW SETPOINT – DHW DIFF) a

boiler will be enabled.

NOTE: DHW MASTER? YES is only to be

used WITHOUT a Header Sensor. When both a
Header Sensor and a DHW Tank Sensor are
installed, because it has a HEADER Sensor, the
Boiler will recognize itself as a MASTER.
When DHW BOILER? is also set to YES, the
MASTER will automatically call on other boilers
when the DHW Tank Temperature drops below

(DHW SETPOINT – DHW DIFF) even when no

Page 36

OPTIONAL FEATURES HeatNet Control V3 1.x

Heat Demand signal is present. However, the
MASTER will only enable boilers for space
heating in response to a Heat Demand signal.

10. Finally, go to DHW BOILER?. Select YES. If

JPS1 has not been cut, a message will appear
instructing to do so. Once this is done, the
MASTER boiler will control the temperature in
the tank using as many boilers as it has available
on H-Net.

NOTE: DHW BOILER? Does not need to be
set to YES on MEMBER boilers, only the

MASTER boiler.

NOTE: JPS1 MUST be cut on all boilers

providing DHW.

DHW METHOD 2: DHW Header
Sensor Input

1. This method will control a tank temperature when

the tank temperature setpoint needs to be
maintained for extended periods with minimal
cycling. Multiple boilers can be used via the H­Net, as this method employs the same PID
algorithm as for space heating. For this method, a
tank temperature band needs to be tolerated.
JPS1 MUST be cut on all boilers providing DHW
to ensure the maximum output temperature of all
boilers is limited for DHW operation.

Now, there is one more thing to consider, the

pump’s post purge time. Dumping the heat from

all boilers (that were running) using a pump post

purge cycle will have an effect on the tank’s

water temperature. Consider this when

establishing the local pump’s POST PURGE
TIME.

3. Connect the Local Pump relay contact on J13 to

enable the DHW pump. Set its post purge time to

dump the boiler’s heat into the tank when the
boiler shuts off. Be aware that this may heat the

tank above the setpoint’s upper heat band
temperature.

4. Enable the system by placing the

LOCAL/REMOTE switch on the Master to the
LOCAL position.

DHW METHOD 3: Space Heating
with DHW Override

This method is for controlling DHW utilizing a tank
thermostat connected to a Master or Member boiler.
This method can be used instead of the 10k thermistor
sensor. When the thermostat contact closes across the

input OA OVR (J12A .7 & .8), the control will sense

this closure and enter the DHW heating mode.

2. Use the Heat Demand Control Method 1

located in the CONTROL METHODS section on
page 22. Instead of placing the Header sensor in
the Header pipe, place it in a well in the tank.

The temperature at which boilers are staged ON,
and then OFF is controlled by the
SETUP:BOILERS:HEAT BAND differential.

This can be understood by referring to the
INTRODUCTION section on the MASTER in
the beginning of this manual.

This differential has the added effect of heating

the tank above the tank’s setpoint temperature. If

the tank setpoint is set to 140F and the heat band
is set to 10F, then the tank temperature will rise
to 145F before the first boiler turns off (setpoint
=140F +/-heat band/2). With (2) boilers running,

the SHED BOILER DELAY time could add to

the tank temperature. So, to ensure that all boilers
are shut off at the upper point of the heat band,

set the SHED BOILER DELAY time to 0. This

will effectively turn off all boilers at the upper
heat band point of: (example) 145F.

In this mode, the boiler will fire to 100% and be
regulated by the OPERATE LIM setting located in
SETUP:SETPOINTS. The OP LIM BAND can be

used to keep the boiler from short cycling too much
by limiting the firing rate as it approaches the

OPERATE LIM.

1. Wire the dry contact from the thermostat on the

tank to the input on J12A terminal 7 & 8. Also, at
this time wire any pump or valve from the DHW
Pump relay (normally open) contact (J13
terminals 9, 10) to control flow of the heating

water into the tank’s coil.

2. Enter the DOMESTIC HOT WATER MENU.

When prompted for DHW BOILER?, enter NO.
We will enter YES when we are finished entering

all parameters

Follow the same steps as used to program the 10k
thermistor sensor method, but when asked to

USE SENSOR?, select NO.

Page 37

OPTIONAL FEATURES HeatNet Control V3 1.x

Set the DHW MASTER to NO. A thermostat

can only control (1) boiler. H-Net is not available
with a thermostat on the tank.

Go to the DHW BOILER?, enter and select
YES. The Master or Member will now control

the temperature in the tank.

DHW METHOD 4: DHW using Direct
Control

If the control’s 4-20mA input is set to HIGH PRIORITY the

4-20mA signal, once brought above the 4-20mA starting
current can be used to override any other Heat Demand and
direct modulate the boiler.

This can be set in menu: ADVANCED SETUP:4-20mA
INPUT. It allows a member boiler to be taken offline and

directly modulated by an external control.

If the Master is using it for heating and the 4-20mA is
set to HIGH PRIORITY, an external control can now
output a 4-20mA signal which will take over the

boiler’s fire rate and override all other heating

demand inputs. This is typically used for DHW
control.

Page 38

WIRING CONNECTIONS HeatNet Control V3 1.x

Wiring Connections

Figure 29 Dip Switches and Wiring

Wire Strip Length.

If the terminal blocks are of the screwless type, the wire should be stripped to

10.67mm.

If the terminal blocks are of the screw type, the wire should be stripped

Typical Settings for KN30:

S5 SETTINGS

4-20mA 1

OFF 2 ENABLE

NONE 3

NONE 4
J4.3-J4.7, PWM 5
J4.1-J4.5, PWM 6

BLOWER PWM 7

135 OHM ENABLE

10K STACK
PLATINUM STACK
J4.3-J4.7, 0-10V
J4.1-J4.5, 0-10V
BLOWER 0-10/20V
PROG USB CHIPNORMAL USB 8

Factory:

JP2 = 2-3

to .25” or 6.34mm.

.42” or

JS1:

Shunt 1-2 = 0-10VDC

Shunt 2-3 = 4-20mA

J4.1 &.5

P3:

No Shunt

Boot Loc 0

4-20mA Input

select, See:

Figure 32

Modbus &

HeatNet

Termination.

See: Figures 33

& 30

S5 Dip switches 1,5,7,8 set the Outputs of the J4 Connector.

S5.1) Set to position 4-20mA for J4.1+ and J4.5- 4-20mA current mode (JS1 = 4-20mA).

Set to position 135 Ohm for J4.1(W), J4.7(B), and J4.5® 135 Ohm mode (JS1 = 4-20mA).

NOTE: S5.6 must be set to J4.1-J4.5, 0-10V for the above to work in 4-20mA mode

S5.2) NOT USED (Factory)
S5.3) Set to NONE if there is no Stack Sensor or if a 1k Platinum stack sensor is used.

S5.4) Set to NONE if there is no Stack Sensor or if a 10k Thermistor stack sensor is used.

If JS1 is set to 0-10VDC then this switch has no effect on J4.1 and J4.5.

Set to 10k STACK, if a 10k Thermistor stack sensor is connected to J10B.
Set to PLATINUM STACK, if a 1k Platinum stack sensor is connected to J10B.

S5.5) Set to J4.3-J4.7, PWM, Configures J4.3+ and J4.8- for PWM output

Set to J4.3-J4.7, 0-10V, Configures J4.3+ and J4.8- for 0-10 VDC output

S5.6) Set to J4.1-J4.5, PWM, Configures J4.1+ and J4.5- for PWM output (JS1 = 0-10VDC).

Set to J4.1-J4.5, 0-10V, Configures J4.1+ and J4.5- for 0-10 VDC or 4-20mA output
(JS1 = 4-20mA or 0-10VDC). This switch in conjuction with S5.1

S5.7) Set to BLOWER PWM for Ametek Blowers.

Set to BLOWER 0-10/20V for VFD controlled blowers.

S5.8) Set to NORMAL USB = Normal operation

Set to PROG USB CHIP (FACTORY ONLY)

Page 39

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 30 Heating Method 1 H-Net, Master/member

RJ45 HeatNet In and Out

The (2) LEDs on the RJ45 indicate:

GREEN: Transmit Data

YELLOW: Received Data

MODBUS

HeatNet

Boiler to Boiler

Communications

MEMBER: Close to run at Local setpoint.
MASTER: Close to control all boilers and run at System setpoint.

3 wire Shielded

HeatNet In and Out

HeatNet Termination.

Enable: Switches DOWN Position.
Disable: Switches UP position.

Switch shown disabled.

Close this contact to override the outdoor
reset slope and run boiler at the Local setpoint.

Page 40

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 31 Heating Methods 2 and 4: AA-High Fire and High/Low, master or member boiler

Heating Mode 4: High Fire

Close this contact to run boiler at Highfire.

T1 T2

Heating Mode 2: Stage Control Inputs.

T1 or T2 Closed: Lowfire
T1 & T2 closed: Highfire

Page 41

WIRING CONNECTIONS HeatNet Control V3 1.x

Thi

s

/

Figure 32 Heating Method 3 4–20 ma/ 0-10 VDC

24 VDC Return

Channel 1:

4-20mA/0-10VDC

(-)

(+)

(+)

Channel 2:

4-20mA/0-10VDC

(-)

24 VDC

S6 along with the
SETUP:ADVANCED:4-20mA INPUT

2

menu configures the channel for

1

operation.
S6 switch 1 DOWN: 4-20mA channel 1

S6 switch 1 UP: 0-10VDC channel 1
S6 switch 2 DOWN: 4-20mA channel 2

S6 switch 2 UP: 0-10VDC channel 2

Closing this contact enables the 4-20 mA/
0-10 VDC input on channel 1

This Method allows direct modulation of the boiler based on a 4-20 mA control signal. A control
capable of transmitting a 4-20mA/0-10 VDC control signal for the purpose of modulating a boiler
and to control a common system temperature must be used with this method.

NOTE: If using a 0-10 VDC signal multiply any references to current in the manual by .5. Example:
5ma * .5 = 2.5 VDC

f

C

t

t

t

t

Page 42

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 33 Heating Method 5: MODBUS (Optional BACnet or LonWorks bridge — Protocessor)

The pin headers are located on the control (‘U’ shaped) that the
Protocessor bridge module plugs in directly. Align the sockets on the
Protocessor with the pin headers on the control, then press into place.
Communication from the Protocessor bridge to the H-Net control is also
handled through the sockets.

Next, connect the BACnet or LonWorks network cable to the Protocessor
module or configure the bridge
use the DIP switch to enable termination.

using the software tools. Once connected

The (2) LEDs on the RJ45 indicate:

GREEN: Transmit Data

RJ45 Cat 5

YELLOW: Received Data

Modbus

3 wire Shielded

Modbus

Modbus Termination.

Enable: Switches DOWN Position.
Disabl e: Switches UP position.

Switch shown disabled.

DIP Switch shown:
NOT Terminated

RJ45 Configuration
and IP connection

NOTE: Do not plug the Protocessor
module in with power on or the
Protocessor module may be damaged.

Protocessor Bridge Module Plug-in.
LonWorks or BACnet bridge which
Can be used instead of the
MODBUS input.

ĚĚŝƟŽŶĂůƵůůĞƟŶƐĂŶĚ/ŶƐƚƌƵĐƟŽŶƐĨŽƌŽŶĮŐƵƌŝŶŐŶĞƚŽƌ>ŽŶtŽƌŬƐĂƌĞĂǀĂŝůĂďůĞŽŶƚŚĞǁĞďƐŝƚĞĂƚŚƩƉ

ǁǁǁŬŶƐĞƌŝĞƐĐŽŵ

Page 43

Shielded/Twisted Pair Connection
(MSTP/LonWorks)

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 34 Relays, Interlocks and Boiler Status

Low Voltage
Interlocks, 24VAC

Remote 120 VAC
Operator

JUMPER
WIRE if
not used

The Highest priority

SYSTEM FLOW PROVE ---------

Low Water Cutoff------------------­Variable Frequency Drive-------­Gas Pressure (High & Low) -----

Spare for user or Factory ------

Operator-----------------------------­Water Flow Switch-----------------

Factory ------------------------------

1
2
3
4
5
6
7
8

USB and Flashdrive Ports:

Used by HeatNet Pro and
updating firmware.

Low Fire Hold: Fires the boiler at
the minimum rate while in
Calibrate. This functions exactly
as the T1 input

Calibrate: Allows adjustment of
the Minimum Fire, Maximum
Fire, and Pilot Ignition settings.

Damper Control

Power Open/ Power Close Valve

Stage Control

Local Pump or

Combustion proving switch
from Combustion Air Damper.

DHW Pump or

Alarm

Power Open/ Power Close Valve

Page 44

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 35 Temperature sensors

(REQUIRED) Water Temperature

T

All Temperature Sensors are 10k Thermistors.

Immersion sensors require a well.

INLET (return) of Boiler

(OPTIONAL) Water Temperature

Common System Supply (Header)

T

IF CONNECTED, BOILER = MASTER

(REQUIRED) Water Temperature OUT (supply) of Boiler

(OPTIONAL) Outside Air Temperature Sensor

T

T

(OPTIONAL) DHW Temperature Domestic

T

Hot Water Temperature (TANK)

(OPTIONAL) Stack Temperature

T

(OPTIONAL)

T

System Return Temperature

Page 45

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 36 Typical Single Boiler System

HEADER SENSOR

(Determines Master Boiler) #4

OUTDOOR

SENSOR

North Away

From Exhaust

#1

LOCAL PUMP

ENABLE #8

FLOW PROVE

#10

RETURN

SENSOR

#3

COMBUSTION AIR

DAMPER

ENABLE #7

PROVE #11

#9

BOILER

#10

SYSTEM PUMP

ENABLE #14

FLOW PROVE #9

SUPPLY
SENSOR

DHW TANK

SENSOR #5*

DHW TANK

AQUASTAT #13

#2

DHW RETURN
DHW SUPPLY

DHW TANK

DHW PUMP
ENABLE #12

#2

#1

#3

#4

#5

#14

#7

Connections

IGN Control

High Limit

#8

#12

#13

#11

*Note: When using DHW

MASTER? YES, a Heat Demand

Heat Demand*

signal must be used to activate

the system.

Page 46

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 37 Using a 4–20ma signal for direct modulation

0ma

No Effect

Once boiler starts the
control signal must
drop below 4.01 mA
to stop Boiler

Boiler Off

0%

Boiler Off

4mA 20mA

A control signal greater
than 4.2mA (adjustable)
will start boiler.

Output Range From

Control

Control Signal

Display input % of control when running

0%

20%
25%

33%

Control Signal to MAX Output

20% for 5:1 boilers
25% for 4:1 boilers
33% for 3:1 boilers

100%

MAX

OUTPUT

100%

Percent of Boilers

INPUT

Percent of Boilers

OUTPUT

0%

0%

Blower Off

Boiler Off

20% = the
minimum speed
the VFD will run

20%

20%
25%

33%

Boiler Output

PWM Duty Cycle

Ignition

80% 100%

Blower Fully ON

100%

Percent of Boilers

Output

After Ignition
20% for 5:1 boilers
25% for 4:1 boilers
33% for 3:1 boilers

Ignition

Page 47

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 38 Common system damper wiring

MEMBER BOILER 2

Connection if Member

boiler is running as

Failsafe

DAMPER

Prove Switch

MEMBER BOILER 1

MASTER BOILER

NOTE:

Ensure that the Combustion Air
Damper is enabled on all Boilers for use.
SETUP MENU:AUX FUNCTIONS

24 VAC

DAMPER

DAMPER

Enable

Mains

24 VAC Ret

Connect to 24 VAC Return

on each Boiler

Page 48

DAMPER 24 VAC

Transformer

WIRING CONNECTIONS HeatNet Control V3 1.x

Figure 39 Failsafe common system pump wiring

120 VAC Return

DPST

Relay

Add additional relays/

contacts for more boilers

MEMBER BOILER 1

System Flow

Prove Switch

120VAC

System Pump

Voltage Return

System Pump

120 Return

System Pump

Contactor

120VAC

System Pump Voltage Feed

Ph2
Ph3

MASTER BOILER

Page 49

Calibration HeatNet Control V3 1.x

Calibration

The calibration of the KN-Series boiler

should only be performed by a
licensed technician.

To enter the calibration menus, place the S2 switch on the
main control board to the CAL position.

Be sure to set this switch back to NORM when the
calibration is complete, otherwise no external control inputs
will work (except T1-T2), the display will always indicate
CALIBRATE and some of the runtime temperatures will
not be displayed.

Press the arrow keys until MIN VFD is shown in the
display, along with the minimum percentage value at which
the boiler is to run at min fire. While in Standby (no call for
heat on inputs), the minimum percent may be preset. To set
the minimum rate while running, any (1), and only (1) of the
(T) inputs must be closed in order to set the boiler to
MINIMUM fire. Press the SELECT key for approximately
1 second. The Percentage value will start flashing,
indicating that it can be adjusted. Adjust the Minimum value
to the desired setting using the arrow keys. The Minimum
setting is clamped to its lowest rated setting and cannot be
adjusted below this. Once you are done with this setting,
press the SELECT key until the value stops flashing. The
new setting is now saved.

The MIN VFD setting, the MAX VFD setting, and the
Ignition setting can be adjusted in the calibration displays.

The values can be changed while running ONLY IN
MINIMUM FIRE (any, but only one of the T inputs closed).

Prior to ignition, the values may be changed, but the blower
will not operate.

The Low Fire Hold switch is located near the

Calibration switch.

Press the Arrow key to select the IGNITION percent. The
Blower speed will be set here to provide the rate for
ignition. While in Standby (no call for heat on inputs), the
Ignition percent may be preset, before firing the boiler. To
set the ignition rate while running, any (1), and only (1) of
the T inputs must be closed Pressing the SELECT key here
will cause the IGNITION setting to flash and the boiler will
ramp to the ignition setting. Adjust it using the arrow keys
and then press the SELECT key until the value stops
flashing. The new setting is now saved.

Page 50

LOG ENTRY HeatNet Control V3 1.x

SET

:05:42P

H2O 127° F

MO D%

1

3

10/14

13

OA

65°F

140°F

57

P

------

HHD

M

PB

Valve, Pilot Valve, Blower, and the Ignition alarm). The #

Log Entry

The KN-Series H-Net control contains a log that records the
major activity (events) in the operation of the boiler. This
activity includes interlock faults, boiler starting and
stopping events, power cycles, misc. faults, and types of
calls-for-heat (control inputs). Setting the time clock to an
accurate time and date is very useful when events are
recorded, since the control will time stamp each snapshot. If
the system is configured to run with HeatNet, then only the
Master boilers SYSTEM TIME needs to be entered. The
Master will then set the time on all Member boilers.

The log is primarily used as a troubleshooting and
diagnostic tool, but may be used as a performance tool to
view run time cycles.

of boilers that are displayed is limited to 7 if the boiler is the
MASTER. If boilers #8 and up need to be viewed, the

Boiler Control Pro software will need to be used. The Last

2 characters on the fourth line indicate the heating mode the
control is in. The modes are:

NC = No Call for Heat

HD = Heat Demand (MASTER and Local modulation

control using PID control, MASTER and
MEMBER)

RM = Remote Modulation from 4-20ma input

HF = High Fire from ALL T-inputs closed or the AA

input

1T = Low Fire from any 1 T-input closed (Low Fire or

High Fire)

An event in time of the boiler’s state is presented via

multiple screens. Each screen event can be stepped through
using the arrow keys.

The top line displays the time and date the event occurred.
In the top right corner, the event # is displayed so that easy
indexing can be done using the arrow keys. The second line

displays the Water temperature of the boiler’s output

(supply) and the Setpoint temperature. The third line

displays the Outside Air temperature, and the Modulation.

The bottom line is used to record the control state of the
boiler.

The control state is defined as the Boiler(s) that is running,
the Circulator Pump state, and the ignition condition (Main

Figure 40 Log entry display

Time

2T = Mid Fire from any 2 T-inputs closed (Low fire or

High Fire )

OP = Option input Active

HT = H-Net Control using the Heat-Link

communications cable

The bottom line is also used to indicate an interlock or limit
that has tripped. It may also indicate a sensor that has failed.
When this occurs, the normal bottom line in the display is
not visible, and the sensor fault is displayed.

For details on messages that appear on the fourth line: See

Appendix B.

Stamp

Event

number

Water Setpoint

Outside Air

Temperature

Boiler 1 On

Boiler 2 On

Boiler 3 On

P = Circulator Pump

S = System Pump

D = DHW Pump

Boiler 7

(Ver 2.x control)

M = Main Valve open

P = Pilot Valve open

Modulation PWM %

NC = No Call for Heat
HD = Heat Demand
RM = Remote Mod 4-20ma
HF,1T, 2T, 3T = T-inputs Fire Rates
HT = H-NET Control

H= Honeywell Alarm

B = Blower ON

Page 51

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

MENU

DEFAULT

VALUE

BOILERS

# OF BOILERS

1

(1-16)

If operating as a member.

LEAD BOILER #

0

(0-16)

# of first boiler to run, determines the fire order in rotation. A

LEAD BOILER #

# of first boiler to run, determines the fire order in rotation. A 0
disables the Lead Boiler function. Firing Mode determines lead.

HEAT BAND

30qF

(2 -50 qF)

Differential temp around setpoint used to stage boiler(s) OFF/ON

HNT

This line displays the boilers auto detected by H-Net. While M is the
Master boiler the numbers are the H-Net address of each boiler from
2–16.

SETPOINTS

LOCAL SETPT

160 qF

(40-220 °F)

Local setpoint used to maintain temperature of SETPT SOURCE

OPERATE LIMIT

When running as a member, boiler shuts off when supply
temperature
Boiler restarts at lower temp of OP LIM BAND or 10F whichever is
lower

LOCAL SETPT

160 qF

(40-220 qF)

Local setpoint used to maintain temperature of SETPT SOURCE

OP LIM BAND

20qF

(1-50 qF)

Limits external input % when in (OP LIM - OP LIM BAND)

SETPT SOURCE

AUTO

4-20mA

AUTO = Local/ System/ WWS Setpoint is used
4-20mA input is mapped to a setpoint.

OUTDOOR AIR RESET

OA RESET

OFF

Outdoor reset ratio (boiler water temp/outside air temp).

WARM WEATHER SD

If set to YES, the boiler /system shuts down when the temperature
exceeds the WWS SETPOINT.

WWS SETPOINT

Temperature at which boiler shuts down, operation is below this.
If boiler is running using either OA RESET or WWS and the OA
OVR input is closed the OA RESET slope is overridden and runs at
local setpoint until OA OVR input opens.

SET OA SETPOINTS

WATER TEMP
At
HIGH OA TEMP

Boiler water temp setpoint when OA temp is at HIGH OATEMP
These four setpoints determine the OA reset slope.

WATER TEMP
At
LOW OA TEMP

Header/Supply setpoint when OA Temp is at LOW OA TEMP

PUMP OPTIONS

SYSTEM PUMP

POST PRGE TIME

2 minutes

(2-60min)

Time in minutes to keep system circ. pump on after boiler stops

PUMP ROTATION

New menu screen

NONE

SYS HRS

PUMP HRS

SYSTEM PUMPS

1

1 or 2

The number of system pumps connected.

If ROTATION is set to SYS HRS, ROTATE TIME is used to switch
pumps when this time expires.
actual time the system pump is enabled.
purge time.

Default Settings & Menu Item Descriptions — SETUP

0 (0-16)

M (M-16)

AUTO

215 qF (45-230 °F)

RANGE DESCRIPTION

reached.

NO

ROTATION: NONE

ROTATE TIME 240 hrs 1-1000 hrs

68qF (40 – 100 qF)

140qF (60 – 190 qF)

10qF (-35 – 40 qF)

This time is measured against the

This would include a post

Page 52

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

If ROTATION is set to PUMP HRS, ROTATE TI
switch pumps when the pump
R

Whichever pump has the least time and is at least

below the other (pump’s time

enabled state.
pumps.

MORE MENUS

New menu screen follows.

This menu allows the clearing of a pump’s runtime counter.
Discretion is advised in clearing only one pump

’s hours after

replacement and the

n using ROTATION set to PUMP HRS. This

would cause the pump whose runtime was cleared to run until it’s

time exceeded the other older pump.

Indicates how many hours the HeatNet control has accumulated on
pump 1.

Indicates how many hours the HeatNet control has accumulated on
pump 2.

ALWAYS ENABLED

ON = Pump never shuts off. Used when there is only 1 system pump
in the system.

SUMMER PUMP JOG

Used with Outdoor Reset, Jogs the local and system pump(s) for
POST PRGE time when system is in summer shutdown. Jog once a
week @12:00

The menu item OVR ENAB IN WWS and ALWAYS ENABLED
must be set to OFF for the jog function to work,

OVR ENAB IN WWS

Priority mode for the system pump while in Warm Weather
s
the OR OVR override input is closed. When set to OFF, the system
pump will not come on while in WWS with the OR OVR override
input closed.
JOG.

LOCAL PUMP

DELTA TEMP ENAB

ON: Use Delta temperature to shut pump off when temperature
across boiler is less than DELTA TEMP setting.

DELTA TEMP

10 °F

(2 – 50 qF)

POST PRGE TIME

2 minutes

(1-60min)

Time in minutes to keep local circ. pump on after boiler stops

ALWAYS ENABLED

OFF

Pump never shuts off.

PUMP/VALVE OPTIONS

MASTER PUMP/VALVE

REMAINS ON:

ON: The master boiler will keep its pump/valve on when no boilers
are running. Prevents deadheading the system flow.

LOCAL PUMP VFD

ON: Outputs a 0-10VDC or 4-20mA signal from J4 pins 1 & 5 that is
proportional to the fire rate of the boiler. Connect to a VFD
controlling a Local pump.

FLOW PROVE

This is an adjustable flow proving time to allow slower valves to
open before proving flow.

NIGHT SETBACK

SETBACK ENTRY

1

(1 – 4)

Four setbacks to adjust setpoint during a time period

ENTRY IS

OFF

Enable or disable the use of this setback

SETBACK

20 qF

(0 – 50 qF)

Temporarily subtracts this temp from the setpoint

START DAY

MON

Day of the week to begin setback or a day range

TIME

12:00AM

Time to begin setback

END DAY

MON

Day of the week to end the setback or a day range

ME is used to

’s time difference is greater than

OTATE TIME.

- ROTATE TIME) will switch to the

This selection is used to equalize run time on the

ZERO RUNTIME PUMP1 PUMP1- PUMP2

PUMP1 TIME 0-999999 hrs

PUMP2 TIME 0-999999 hrs

OFF ON/OFF

OFF

OFF ON/OFF

OFF

OFF ON/OFF

OFF ON/OFF

ON/OFF

MON-SUN

AM.

hutdown. ON: The system pump is allowed to run in WWS when

Enabling this feature disables the SUMMER PUMP

10s 10-240 sec

Page 53

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

TIME

12:00AM

Time of the day to end the setback

OPTIONS

TEMP SCALE

qF

(F or C)

Fahrenheit scale is default

KEY CLICK

ON

Beeps when a key is pressed

SKIP PASSWORD

ON

Disables the Password

BRIGHTNESS

50%

(25, 50,75,100)

Four levels of display brightness, lower for longer life of the display

LOG/RUNTIME

RUN HOURS

Displays runtime hours. Total time the main valve has been open.

DATA LOG ENTRY

Displays the current entry in the data log

SIZE

Displays the current size of the log in entries

BOILER CYCLES

Displays completed boiler cycles. Incremented when the main valve
turns OFF after it has been ON. Does not include attempts to light.

AUX FUNCTIONS

COMBUST AIR

DAMPER

The LINKED/COMMON setting allows one common damper to be
used and controlled by the Master Boiler. All Member boilers must
have their damper prove inputs wired as per
system damper wiring

Features:

INDEPENDENT: Individual

dampers are in controlled by their respective boiler.

If set to YES, then OUTPUT RELAY K5 can be used to control a
combustion air damper. The Master can control a common system
damper or an individual damper. Members control their respective
damper independent of the Master. Relay K5 is used to enable the
com
wiring, page 48. Needs to Prove the damper is open.

The damper prove input is dedicated to connect at J12B terminals 7
and 8.
wiring diagram.

This is the proving time in minutes for the combustion air damper
prove switch. It is sensed at J12B Pin 7. If the damper faults, a retry
will occur every 10 minutes in attempt to open the da

mper.
When using J12B in a common damper configuration, wiring is done
beginning with the Master boiler. J12B Pins 7,8 are connected to the
prove switch of the combustion damper. Pin 8 is supplying 24 VAC
and pin 7 is the sense input. A second wire is connected to J12B pin
7 of the Master and the other end connected to the first member
boilers J12B pin 7. If another member boiler is present, connect
another wire to the J12B Pin 7 terminal of the first member and the
other end to the second member boiler

J12B pin 7. Continue this

method for each additional boiler.

ALARM SILENCE

ALARM SILENCE IN

This menu allows the configuration of the Alarm Silence switch. It
can be disabled so th

at the Alarm Silence switch cannot silence the

alarm until the

alarm is cleared; ALARM SILENCE = NO. The

default value is to enable the ALARM SILENCE switch.

Holding
down the BACK and SELECT keys at the same time may also be
used to silence the alarm.

If a stack sensor is used, holding down the BACK and SELECT keys
at the same time is the only way to silence the alarm.

FAILSAFE MODES

RUN IN LOCAL IF:

H-NET COMM LOST

If this entry is set to ON and the Member boiler does not see any
communications coming from the Master boiler, this boiler will run

TYPE

IN USE? YES

INPUT:

PROOF TIME 2:00 (0 – 4m in)

J12B.7

DAMPER

LINKED/COMMON

INDEPENDENT

Figure 38, Common

, page 48. Also see Section: Optional

Auxiliary Function Options

bustion air damper. See Figure 38, Common system damper

If using a common damper refer to the common damper

USE?

INPUT = J10B STACK

YES

OFF

Page 54

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

in LOCAL. The boiler will continue to run in LOCAL until
communications are re-established or this entry is set to OFF.

This entry may be set to one of the temperature sensors: SUPPLY,
HEADER, RETURN, or turned OFF (default). If this entry is set to a
sensor and the temperature falls below TEMP, the boiler will
automatically start and run the water temperature up to the LOCAL
Setpoint and then shut OFF.

This is the temperature that the selected sensor must fall below for
the boiler to start.

DEFAULT

VALUE

HEAT EXCHANGER

This is the maximum differential temperature the heat exchanger can
see before the LIMIT RATE feature is activated, and a log entry is
made.

Limit to Half Rate: When set to YES, and the maximum differential
temperature (delta T) has been exceeded, the fire rate called for is cut
in half. In other words: if we are calling for 80% modulation and
have exceeded the delta T, the boiler will only fire at 40%. The delta
T needs to drop 10F below the maximum delta T to reset this limit.
The message “ ½ INPUT” will be displayed on a member boiler and
a Master Boiler will display the Modulation % for the system even
though it is running at ½ of this rate. This method helps protect the

heat exchanger from damage due to excessive delta T’s. If this

Master boiler is running

This time may be used to remove condensation that is still present on
the heat exchanger after the boiler has finished running. The time
may be adjusted to 600 seconds
fixed
interrupted by a call for heat.

If the extended post purge is active, an ‘*’ will be displayed next to

“STANBY * ”. This indicates that the boiler is still ready to run, but

is completing an extended post purge. As always, the STATUS
screen will display the meaning of the ‘*’. In this case: EXTEND PP.

DOMESTIC HOT WATER (Version 2.x control)

Setting this value to YES enables the Boiler/System for DHW
operation. DHW settings are only looked at if set to YES.

DHW SETPOINT

160 qF

40 – 200 qF

Setpoint that the boiler/system will target when a call for DHW.

DHW SETPOINT – DHW DIFF : if DHW water temperature is less
than this

temperature, the Boiler/System will enter DHW Heating

mode. Once the DHW SETPOINT is reached, DHW mode is exited.

If this entry is set to YES, the DHW 10k Sensor is looked to for
controlling DHW water temperature. If set to NO, A thermostat is
used.

If the DHW PRIORITY is set to YES, then when there is a call for
DHW, the system pump shuts off. If NO, the system pump stays on.

This is the time that the DHW relay remains on after the DHW call
ends.

This parameter can only be used if USE SENSOR? is set to YES,
and there is NO Header sensor
If set to YES, this boiler becomes the DHW Master Boiler and will
use HeatNet to control member boilers based on the DHW Sensor,
DHW SETPOINT, and DHW DIFF. If set to NO, only this boiler
will run in DHW mode.

SYSTEM CLOCK

LOW TEMP OFF

TEMP < 40F

MENU

EXCHR DELTA T

LIM-> HALF RATE YES

EXTEND PP TIME: 0s 0-600s

40 qF 35-200 qF

RANGE DESCRIPTION

60 qF 1 to 120 qF

(10 minutes). Unlike the 10 second

post purge time the extended post purge time may be

DHW BOILER? NO

DHW DIFF

USE SENSOR? NO

DHW PRIORITY NO

POST PURGE 120s 0-600 secs

DHW MASTER? NO

5 qF 1 – 30 qF

Present..

Page 55

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

TIME

This time nee
power has been lost for more than 3 days. The time is only required
for an accurate log entry time

DAY OF WEEK

MONTH

DAY

YEAR

The SEL key must be pressed after all time values have been entered
to save all time values at once.

DISTRIBUTED CTRL

CONTROL

H-Net

Displays method of operation: HeatNet (H-Net)

Auto detected, based on the HEADER sensor.
If the
Series control is run as a H
If the HEADER sensor is not TYPEZ, H-Net MASTER = NO.

The local address is the address of a member device. This is
normally in the range of 2 through 16. But if the

Series control is
a MASTER, then the default address is 255. The H-NET ADDRESS
# is synonymous with boiler #.

The MODBUS address is for communicating with Laptop, PC, or
other MODBUS capable device. It is the 2nd communication port
reserved for host control.

MODULAR BOILER SET

This is the delay time in 30sec intervals, before starting a new boiler.
Boiler #1 is started immediately after a call for heat. If a second
boiler needs to start, the ADD BOILER DELAY will need to expire
before starting.

This is the delay time in 30 second intervals, before stopping a
boiler. A boiler is stopped immediately when the top of the heat band
is exceeded. If a second boiler needs to stop, the SHEDBOILER
DELAY will need to expire before stopping.

MODULATE DELAY

TIME

This is the time the boiler remains in min-fire before it relinquishes
control to the modulation % signal.

MOD MAX – LAST FIRE

This value represents the maximum % of input on the boilers if all
the available boile
clamp is removed and all boilers are allowed to modulate up to

100%. When this value is limiting the input an ‘*’ is displayed and
the “INPUT CLAMP” message is displayed in the STATUS screen.

This value is derived by: multiplying twice the minimum fire rate of
the boiler with the least turndown (2* turndown(20% 5:1, 25% 4:1,
33% 3:1)).

system, or when “bumps” in the temperature occur as b

added and subtracted, this value may need adjustment. The
adjustments will help produce smooth temperature control when each
boiler is started and stopped. This method ensures that, once a new
boiler starts to fire, and holds its fire rate at the minimum setting, it
does not add its BTU output to a boiler already firing at 100%. The
boilers can not be fired starting @ 0%, but start at a minimum
(example: 20%) and introduce a minimum amount of BTUs into the
system. Section: SETUP & OPERATION

ds to be entered at first turn-on and in the event that

-stamp and fault time stamp.

PRESS SEL TO SAVE

Default Settings & Menu Item Descriptions — ADVANCE D SE T U P

H-Net MASTER YES

H-NET ADDRESS 255 (2 –16)

MODBUS ADDRESS

ADD BOILER DELAY

1 (1 – 247)

10mins (0 – 15min)

HEADER sensor is present and is set to TYPEZ, the KN-

-Net MASTER (YES).

KN-

SHED BOILER DELAY

2mins (0-15min)

10 secs (0 – 60min)

70% (25 – 100%)

rs are not firing. Once all boilers are firing, this

In mixed boiler size configurations, more than (2) boilers in a

oilers are

Page 56

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

The MOD MAX value is also applied when using the AA terminal
for High Fire and when using the 4
modulation. When these demands for heat are used, the maximum
modulation the boiler can obtain when first starting is equal to the;
ADVAN
LAST FIRE:. The timer value ADVANCED SETUP: MODULAR
BOILER SET:ADD BOILER DELAY is used in conjunction to limit
the modulation for this amount of time. Once the boiler has fired and
the ADD BOILER DELAY time expires
available. This change is a protective means for extending the life of
the heat exchanger which may consistently be exposed to thermal

stress.

ADAPTIVE MOD

If MODULATION MODE is set to ADAPTIVE on the Master
boiler, the Master lowers the system modulation rate of all currently
running boilers before a newly started boiler enters the Main Valve
state. Upon entering the Main Valve state of a newly fired boiler, the
Master waits the DELAY RELEASE time before allowing the PID to
resume modulation control. With MOD MODE set to ORIG KN,
The Master boiler keeps firing at the current modulation rate when a
new boiler is added and lets the PID adjust modulation rate
accordingly.

If drop down is set to ON PILOT and MOD MODE = ADAPTIVE,
and when a newly added boiler starts, the system waits until it enters
its PILOT state before bring the system modulation down. This
allows for the system to prepare for the new energy that is to be
introduced. If DROP DO
modulation is lowered as soon as the newly added boiler is called.

Once the Main Valve opens on the newly added boiler and the MOD
MODE = ADAPTIVE the Master waits this amount of time before
releasing
added boiler to accumulate some soak time.

FIRING MODE

LOFO: Boilers are fired Last On, First Off starting with Lead Boiler
FOFO: Boilers are fired First On, First Off
TRUE: Boilers are fired based on the runtime they report back to the
Master boiler. Boilers with the least runtime are fired first and boilers
with the most runtime are stopped first.
MIXED: Different types of boilers can be mixed in a system and
fired based on (2) Priority sets. Boilers are started and stopped with
in the Priority sets based on their runtime hours.

When the firing rotation is based on runtime, this value represents
the interval in hours of runtime before rotation occurs. Boiler

to

Boiler.

This is the time in minutes that the boiler must remain OFF before it
can be fired again.

There are (2) Priority settings used by the MIXED boiler rotation
algorithm. Priority 2 is the defaul

t and lowest priority. Priority 1
Is the highest priority. A Priority may be assigned to a set of boilers
which fires and rotates based on time and is independent of the other
Priority set.

YES: Predicts the boiler restart point in the heating band while the
temperature of the boiler is drifting down through the band. The
purpose of this is to ensure the temperature remains in the

the boiler is stopped and started at low inputs.

-20 mA input for direct

CED SETUP: MODULAR BOILER SET: MOD MAX –

, the full modulation is

MOD MODE ADAPTIVE

DROP DOWN ON CALL

DELAY RELEASE 0s

MODE TRUE

MIN RUNTIME 10 (1-750)

MIN OF F TIME 0 (0-10m)

FIRING PRIORITY: 2 1 or 2

WN is set to immediately, the system

the PID to control modulation. This allows for the newly

PREDICT START: YES YES/NO

temperature band. It also minimizes temperature swings when

Page 57

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

BASE LOAD BOILER

BASE LOAD BOILERS:

This setting works in conjunction with the ADVANCED SETUP:
SYSTEM:OPTION setting BASE LOAD. Currently only (1) base
load boiler is supported using relay K8

(START>MOD,

START<OA T,

START>RET)

Used in Conjunction with DELAY TIME.

START>MOD

100%

(20–100)

The base load relay K8 will close when the Modulation is >%.

START<OA T

(40–140)

The base load relay K8 will close when the OA temp is > T

START>RET

(60–150F)

The base load relay K8 will close when the Return temp is > T.

(FIRST,

START>RET)

STOP<MOD

20% (20–100)

20% (20–100)

The base load relay K8 will open when the Modulation is <%.

STOP>OA T

(40–100 qF)

The base load relay K8 will open when the OA temp is > T.

STOP<RET

(60–150 qF)

The base load relay K8 will open when the Return temp is < T.

This setting allows a wait time before firing the base load boiler
once the start condition is met.

SENSORS

Sensors can only be changed when there is no call for heat. The boiler must be in STANDBY.

The first (4) sensor #’s are reserved as: OUTSIDE AIR, water

SUPPLY outlet, water RETURN inlet, and system HEADER
temperature. If the HEADER sensor is
performs the tasks of the MASTER boiler. If the HEADER sensor is
set to NONE, its function is the MEMBER. The remaining (2)
sensors perform as user selections and provide functions such as:
Combustion Air Proving.

There are (4) sensor types:
NONE = do not use this sensor
TYPEZ = 10k thermistor
ON/OFF = 5 volts supplied out to detect a contact/switch closure.

Placing a precision 10k (TYPEZ) precision resistor across the sensor
input selected allows calibration of the sensor input.

4–20mA INPUT

ANALOG IN CHANNEL:

There are (2) channels that may be configured for 4-20mA inputs or
0
These inputs are used to direct fire a boiler or to remotely control the
setpoint of the boiler.
used for direct modulation and remote setpoint control.

10VDC

Type of input to use for the ANALOG IN CHANNEL selected
above. The dip switch S6 also needs to be set correctly in
conjunction with this setting.

When using 4-20mA setpoint control in SETPOINTS:SETPOINT
SOURCE. This is the temperature when a 4ma signal is applied and
is tied to the BOILER START mA. The Setpoint will then be
mapped from 4mA –20mA and example default of: 50-220F

20mA SETPOINT

220 qF

50-220 qF

This is the setpoint temperature when a 20mA signal is applied.

This is the current value which will start the boiler. There is a .1mA
hysteresis value. So if the Boiler starts at 4.11mA it shuts off a

4.01mA.

If the Priority is set to NORMAL, the boiler responds to its HEAT
DEMAND inputs in the Priority that is outlined in the Control

0 0-1

START >MOD

STOP FIRST

DELAY TIME 0 (0–60 minute s)

SENSOR #

STOP<MOD,

START>OA T,

used (TYPEZ), that boiler

TYPE

CALIBRATE

1 1 -2

CHANNEL MODE: 4-20mA 4-20mA or 0-

4mA SETPOINT

BOILER START 4.11mA 3.71-5.0mA

PRIORITY NORMAL

50 qF 50-220 qF

-10VDC inputs. They are labeled 4-20mA (1) and 4-20mA (2).

Analog channel (1) is the primary channel

Page 58

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS Heat Net Control V3 1.x

Methods section. If the PRIORITY is set to HIGHEST, The 4-20ma
input responds at the highest Priority level (same as the AA input).
This method may be used by an external control to override the
HeatNet control and fire the boiler using this external control
(external control override). This allows for complex DHW control
systems.

PASSWORD

AAAAAA

COMMUNICATIONS

1200, 2400,

BAUD 19200

DATA FORMAT 8E1

SETPOINT TIMER YES

FACTORY CAL?

FACTORY RESET? NO

ACCELERATE 3.0%/s .1 – 10.0 %/s

DECELERATE 3.0%/s .1 – 8.0 %/s

SOFT START SECS: 2 2 – 4 seconds

BOILER TYPE

CONFIGURE INTERLKS

LOAD FIRMWARE NO

SOURCE USB DRIVE

The 24 VAC interlocks can be enabled or disabled for reporting.

4800, 9600,

19200, 38400

8E1, 8N1,
8N2, 8O1

BLOWER SETTINGS (Ametek Blower)

USB DRIVE,

USB CABLE,

SAVE FILE

LOAD DEFAULTS

Provides a limited access for security, though restoring system
defaults will reset the password to the value “AAAAAA”

This is the Baud rate for serial communication from the MODBUS
port. Selectable from 1200, 2400, 4800, 9600, 19200, 38400.

8 bits -Even Parity -1 stop bit, valid settings: 8E1, 8N1, 8N2, 8O1

If set to ‘YES”, the setpoint timer is enabled and requires a periodic

update of its value to keep from timing out and retuning control to
H-Net control. If set to “NO”, MODBUS always has control and on
a loss of MODBUS communications, H-Net does not assume
control.

Selecting YES will load just the factory calibration values: MIN
VFD, MAX VFD and IGN VFD.

Selecting YES will load all factory defaults except the Calibration
values, HeatNet, and Modbus addresses.

If a signal is sent to increase the blower rpm, the blower’ s
acceleration speed will change at this rate until it’s rpm is equal to
the signal sent. % per second. Setting th is value too high may cause
overshooting of the blower rpm and temporarily over firing of the
boiler. Setting this too low will slow down the response of the boiler
to get to setpoint.

If a signal is sent to decrease the blower rpm, the blower’ s
deceleration speed will change at this rate until it’s rpm is equal to
the signal sent. % per second. Setting this value too low will slow
down the response of the boiler to get to setpoint. Setting this value
too high may cause undershooting of the blower rpm and
temporarily dropping below low fire of the boiler (Due to this
condition, the deceleration rate is automatically decreased as the
rpm approaches low fire).

In order to start the Ametek blower, the control signal must be
applied to start the blower at a low rpm. If the low speed start time
is too low the Ametek blower may not start and lock out. If the time
is too high, pre-purge time of the blower is lost.

SYSTEM

Enters the Load Firmware menu. Loading new firmware allows for
upgrades and bug fixes to the HeatNet con t rol. Check the

www.kneries.com website periodically for updates.

Selecting will read the FIRMWARE directory on a
flash drive and display any .hex files located there. Follow the on
screen prompts and then select a file using the arrow keys. Once a
file has been selected, a STORAGE LOCATION needs to be
selected. There are (2) storage locations for the new file. Location 1
is used for normal updates and Location 0 is for the factory stored

USB DR

IVE

Page 59

DEFAULT SETTINGS & MENU ITEM DESCRIPTIONS HeatNet Control V3 1.x

backup file. When the Storage location (default is Location 1) is
selected the file will be loaded into a permanent storage memory
location. Next, the control will reboot and copy this new program
into running memory, reboot, load factory defaults, and then reboot
again.

Selecting
running the Firmware Update program from a PC
takes longer and requires a Personal Computer (laptop) to be taken
to the boiler site. Again, follow the on screen prompts to down load
the program into a storage location as done when using the above
USB DRIVE loading menu.

Selecting

will display the currently stored files in the
storage memory locations. Use the arrow keys to select a stored file
for copying to running memory. When

is pressed the file
will be marked so it will be loaded on the next power cycle. Power
cycle the boiler to begin copying the file from stored memory to
running memory.

NOTE:

shunt on the control needs to be connected and the CAL/NORMAL
switch placed in the CAL position. If the control is power cycled in
this condition
running program. If in the LOAD FIRMWARE menus, STORAGE
LOCATION 0 will be an allowed storage location.

When set to DUAL FUEL, input T3/ RESERVED, OPTION input
is used to control the DUAL FUEL OPTION relay via K8 contacts
on J4.2 &.6. When set to NO OPTION the input T3/RESERVED,
OPTION relay K8 on J4.2 &.6 is inactive.
When set to BASE LOAD, the Option Relay K8 on J4.2 &.6 is used
as an enable contact for a

­20mA output is used to modulate the base load relay if it is of the
modulating type.

BOILER TYPE

The product type allows configuration of the control. The following
fields will be adjusted to the default for the product.

This defines a boiler as condensing or non-condensing. This value is
not used with this version and is displayed only for reference and
future applications.

This is the BTU input rating of the boiler. This value is not used
with this version and is displayed only for reference.

VFD, AMETEK, EBM

This is the blower type associated with the product. This should not
be changed manually.

LOW,MEDIUM,

HIGH

This defines the mass of the boiler. This value is not used with this
version and is displayed only for reference and future applications.

This is the turndown of the boiler. For the KN-series the default is
5:1 and determines the minimum firing percentage. 5:1 = Min 20%,
4:1 = Min 25%, 3:1 = Min 33%
NOTE: The boiler must be set up for operation at this Turndown
rate using the Calibrate settings. This TURNDOWN setting only
controls the displayed percentage.

< 2000 FT,
> 2000 FT,

> 4000 FT

This is the Altitude in feet of where the boiler is installed. On
Ametek Blowers it limits the blower output for low altitudes and
allows a higher output at higher altitudes.

USB CABLE requires connecting a USB cable and

. This process

SAVE FILE

SELECT

to access the factory backup program, the P3 BOOT

, the factory program will overwrite the existing

NO OPTION

OPTION: NO OPTION

PRODUCT: KN6 KN6-KN30

CONDENSING YES

BTU IN 200,000

BLOWER VFD

MASS MEDIUM

TURNDOWN 5:1 3:1, 4:1, 5:1

ALTITUDE < 2000FT

DUAL FUEL

BASE LOAD

base load boiler. The J4.1 &.5 0-10vdc/4

.

Page 60

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

MODBUS Communications

The KN-Series control can be controlled using Modbus commands to Enable/Disable the boiler/system. A connection to the
Console Modbus Port on the Communications board is required. The Master Boiler assumes the role of MEMBER, RTU, 192Kb,
8 bits, Even Parity, 1 stop bit, when connected to a BMS (Building Management System).

The Member Boilers should not be connected to a BMS system other than to view Read Only addresses. Refer to

or gre

http://www.knseries.com/ website f

Address Name Raw Data Type Scale Description Valid Values/Range

40001 HeatDemand 1 bit unsigned ---

40002 SetpointTimer 16 bit unsigned ---

40003 Setpoint 8 bit unsigned 1.0
40004 OAResetEnable 1 bit unsigned ---

40005 OARSetpoint 8 bit unsigned 1.0

40006 OARHighWaterTemp 8 bit unsigned 1.0

40007 OARHighAirTemp 8 bit unsigned 1.0

40008 OARLowWaterTemp 8 bit unsigned 1.0

40009 OARLowAirTemp 8 bit signed 1.0
40010 SetMonth 8 bit unsigned --­40011 SetDay 8 bit unsigned ---

40012 SetYear 8 bit unsigned --­40013 SetHour 8 bit unsigned --­40014 SetMinute 8 bit unsigned ---

ater detail on communicating with Modbus, BACnet, or LonWorks protocols.

Figure 41 MODBUS Input/Output Variables (Read/Write)

Heat Demand/Request. Setting the state
member of this variable will put the boiler
in heating mode.

System Setpoint Timer

The system setpoint timer and system
setpoint work in tandem to externally
control (i.e. a BMS - building management
system) the operating setpoint. The
setpoint (countdown) timer should be
loaded with a timeout value (in seconds)
prior to writing the system setpoint. When
the timer reaches zero, the control assumes
that the BMS is no longer operating and the
local setpoint (saved on the control) is
reloaded. This is a failsafe feature used to
help safeguard the system in case of BMS
failure. If the setpoint timer is not written,
a default timeout value of 60 seconds is
assumed.

System Setpoint (see

Enables/Disables outdoor air reset mode.

Outdoor air reset setpoint. Temperature at
which boiler shuts down.

Boiler water temperature setpoint when
outdoor air temperature is at the high
outdoor air temperature setpoint
(OARHiAirTemp).

High outdoor air temperature setpoint.
Header/Supply temperature setpoint when

outdoor air temperature is at the low
outdoor air temperature setpoint
(OARLoAirTemp).

Low outdoor air temperature setpoint.
Set real time clock – month (
Set real time clock – day (

Set real time clock – year (
Set real time clock – hour (
Set real time clock – minute (

S

etpo intTimer

see SetClock

see SetClock

see SetClock

see SetClock

see SetClock

)

)

)

0 = no heat demand

1 = heat demand

0 – 65535 seconds

)

0 (January) - 11

)

)

40 - 220 °F

0 = disabled

1 = enabled
40 – 100 °F

60 – 19 0 °F

50 – 90 °F

70 – 220 °F

-35 – 40 °F

(December)

1 – 31
0 – 99
0 – 23
0 – 59

Page 61

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 41 MODBUS Input/Output Variables (Read/Write)

Address

Name

Raw Data Type

Scale

Description

Valid Values/Range

40015

SetSecond

8 bit unsigned

---

Set real time clock – second (see SetClock)

0 – 59

Set real time clock – weekday (

see

SetClock)

1 (Monday) - 7

(Sunday)

Set (write) the real time clock.
Do Not Write more than once per minute
To write the real

time clock, the system
variables (SetMonth, SetMonth, SetDay,
SetYear, SetHour, SetMinute, SetSecond,
SetWeekday) must first be loaded with the
correct date and time. Then, a 1 must be
written to the state portion of this system
variable to write the new

date and time to

the system clock.

40018

DHWSetpoint

16 bit signed

1.0

DHW Setpoint

40 - 200 °F

Figure 42 MODBUS Input Variables (Read Only)

Address

Raw Data

Type

Scale

bit unsigned

The number of boilers currently

running.

30002

Modulation

8 bit unsigned

0.01

Current system modulation level.

0 – 100 %

30003

HeaderTemp

16 bit signed

0.01

Header / System temperature.

32 – 250 °F

30004

SupplyTemp

16 bit signed

0.01

Supply temperature.

32 – 250 °F

30005

ReturnTemp

16 bit signed

0.01

Return temperature.

32 – 250 °F

30006

OutsideTemp

16 bit signed

0.01

Outside air temperature.

-40 – 250 °F

30007

Spare1

16 bit signed

---

Raw A/D value from spare 1 input.

-32768 to 32767

30008

Spare2

16 bit signed

---

Raw A/D value from spare 2 input.

-32768 to 32767

8 bit unsigned

0 (January) - 11

(December)

30010

Day

8 bit unsigned

---

Real time clock day.

1 – 31

30011

Year

8 bit unsigned

---

Real time clock year.

0 – 99

30012

Hour

8 bit unsigned

---

Real time clock hour.

0 – 23

30013

Minute

8 bit unsigned

---

Real time clock minute.

0 – 59

30014

Second

8 bit unsigned

---

Real time clock second.

0 – 59

30015

Weekday

8 bit unsigned

---

Real time clock weekday.

1 (Monday) – 7 (Sunday)

30016

Boiler01Status1

16 bit unsigned

Boiler (1 – 16) status flags. These bits

interlocks, ignition circuit, and various

See the “BoilerStatus1” and

“BoilerStatus2” Tables

30017

Boiler01Status2

30018

Boiler02Status1

30019

Boiler02Status2

30020

Boiler03Status1

30021

Boiler03Status2

30022

Boiler04Status1

30023

Boiler04Status2

40016 SetWeekday 8 bit unsigned ---

40017 SetClock 1 bit unsigned ---

Name

30001

BoilersOn 8

---

0 = no action

1 = set/write the clock

Description Valid Values/Range

0 – 16

30009

Month

--- Real time clock month.

indicate the state of the 24VAC

other conditions. See the values

---

column for a list of conditions.

Boiler01 = Master

Boiler02 = Member01
Boiler16 = Member15

Page 62

…

below.

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 42 MODBUS Input Variables (Read Only)

Address

Raw Data

Type

Scale

30024

Boiler05Status1

30025

Boiler05Status2

30026

Boiler06Status1

30027

Boiler06Status2

30028

Boiler07Status1

30029

Boiler07Status2

30030

Boiler08Status1

30031

Boiler08Status2

30032

Boiler09Status1

30033

Boiler09Status2

30034

Boiler10Status1

30035

Boiler10Status2

30036

Boiler11Status1

30037

Boiler11Status2

30038

Boiler12Status1

30039

Boiler12Status2

30040

Boiler13Status1

30041

Boiler13Status2

30042

Boiler14Status1

30043

Boiler14Status2

30044

Boiler15Status1

30045

Boiler15Status2

30046

Boiler16Status1

30047

Boiler16Status2

30048

Boiler01RuntimeHigh16

16 bit unsigned

16) Runtime seconds High

counters. To get the actual runtime for

any given boiler (##), the high and low

Boiler##RuntimeHigh16:Boiler##Runti

30049

Boiler01RuntimeLow16

30050

Boiler02RuntimeHigh16

30051

Boiler02RuntimeLow16

30052

Boiler03RuntimeHigh16

30053

Boiler03RuntimeLow16

30054

Boiler04RuntimeHigh16

30055

Boiler04RuntimeLow16

30056

Boiler05RuntimeHigh16

30057

Boiler05RuntimeLow16

30058

Boiler06RuntimeHigh16

30059

Boiler06RuntimeLow16

30060

Boiler07RuntimeHigh16

30061

Boiler07RuntimeLow16

30062

Boiler08RuntimeHigh16

30063

Boiler08RuntimeLow16

Name

Description Valid Values/Range

Boiler (1 –

(Upper) and Low (Lower) 16 bit

16 bit counters must be combined
(concatenated) into a single 32 bit

--­Boiler01Runtime =

(Boiler01RuntimeHigh16 * 65536) +

Boiler01RuntimeLow16

Boiler01 = Master

Boiler02 = Member01
Boiler16 = Member15

Page 63

counter as:

meLow16

Example

…

0 – 4294967295 seconds

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 42 MODBUS Input Variables (Read Only)

Address

Raw Data

Type

Scale

30064

Boiler09RuntimeHigh16

30065

Boiler09RuntimeLow16

30066

Boiler10RuntimeHigh16

30067

Boiler10RuntimeLow16

30068

Boiler11RuntimeHigh16

30069

Boiler11RuntimeLow16

30070

Boiler12RuntimeHigh16

30071

Boiler12RuntimeLow16

30072

Boiler13RuntimeHigh16

30073

Boiler13RuntimeLow16

30074

Boiler14RuntimeHigh16

30075

Boiler14RuntimeLow16

30076

Boiler15RuntimeHigh16

30077

Boiler15RuntimeLow16

30078

Boiler16RuntimeHigh16

30079

Boiler16RuntimeLow16

30080

Boiler01Status3

16 bit unsigned

flags. These bits indicate the state of

values column for a list of conditions.

See the “BoilerStatus3”

30081

Boiler02Status3

30082

Boiler03Status3

30083

Boiler04Status3

30084

Boiler05Status3

30085

Boiler06Status3

30086

Boiler07Status3

30087

Boiler08Status3

30088

Boiler09Status3

30089

Boiler10Status3

30090

Boiler11Status3

30091

Boiler12Status3

30092

Boiler13Status3

30093

Boiler14Status3

30094

Boiler15Status3

30095

Boiler16Status3

----- The following registers are available starting in firmware version 2.0 -----

30096

Boiler01SupplyTemp

0.01

temperature (if

30097

Boiler02SupplyTemp

30098

Boiler03SupplyTemp

30099

Boiler04SupplyTemp

30100

Boiler05SupplyTemp

30101

Boiler06SupplyTemp

30102

Boiler07SupplyTemp

Name

Description Valid Values/Range

16 bit signed

Boiler (1 – 16) stage control input

---

the stage control inputs. See the

Boiler (1 – 16) supply

available). See BoilerStatus2 to

determine if the sensor is present.

Boiler01 = Master

Boiler02 = Member01

…

Boiler16 = Member15

Table below.

32 – 250 °F

Page 64

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 42 MODBUS Input Variables (Read Only)

Address

Raw Data

Type

Scale

30103

Boiler08SupplyTemp

30104

Boiler09SupplyTemp

30105

Boiler10SupplyTemp

30106

Boiler11SupplyTemp

30107

Boiler12SupplyTemp

30108

Boiler13SupplyTemp

30109

Boiler14SupplyTemp

30110

Boiler15SupplyTemp

30111

Boiler16SupplyTemp

30112

Boiler01ReturnTemp

0.01

16) return temperature (if

30113

Boiler02ReturnTemp

30114

Boiler03ReturnTemp

30115

Boiler04ReturnTemp

30116

Boiler05ReturnTemp

30117

Boiler06ReturnTemp

30118

Boiler07ReturnTemp

30119

Boiler08ReturnTemp

30120

Boiler09ReturnTemp

30121

Boiler10ReturnTemp

30122

Boiler11ReturnTemp

30123

Boiler12ReturnTemp

30124

Boiler13ReturnTemp

30125

Boiler14ReturnTemp

30126

Boiler15ReturnTemp

30127

Boiler16ReturnTemp

30128

Boiler01CyclesHigh16

16 bit unsigned

Boiler (1 – 16) Cycles High (Upper) and

Low (Lower) 16 bit counters. To get the

actual cycle count for any given boiler

counters

must be combined (concatenated) into

Boiler##CyclesHigh16:Boiler##CyclesL

30129

Boiler01CyclesLow16

30130

Boiler02CyclesHigh16

30131

Boiler02CyclesLow16

30132

Boiler03CyclesHigh16

30133

Boiler03CyclesLow16

30134

Boiler04CyclesHigh16

30135

Boiler04CyclesLow16

30136

Boiler05CyclesHigh16

30137

Boiler05CyclesLow16

30138

Boiler06CyclesHigh16

30139

Boiler06CyclesLow16

30140

Boiler07CyclesHigh16

30141

Boiler07CyclesLow16

30142

Boiler08CyclesHigh16

Name

16 bit signed

Description Valid Values/Range

Boiler (1 –

available). See BoilerStatus2 to

determine if the sensor is present.

Boiler01 = Master

Boiler02 = Member01

…

Boiler16 = Member15

32 – 250 °F

(##), the high and low 16 bit

a single 32 bit counter as:

--­Boiler01Cycles =

(Boiler01CyclesHigh16 * 65536) +

Boiler01CyclesLow16

Boiler01 = Master

Boiler02 = Member01
Boiler16 = Member15

Page 65

ow16

Example

…

0 – 4294967295

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 42 MODBUS Input Variables (Read Only)

Address

Raw Data

Type

Scale

30143

Boiler08CyclesLow16

30144

Boiler09CyclesHigh16

30145

Boiler09CyclesLow16

30146

Boiler10CyclesHigh16

30147

Boiler10CyclesLow16

30148

Boiler11CyclesHigh16

30149

Boiler11CyclesLow16

30150

Boiler12CyclesHigh16

30151

Boiler12CyclesLow16

30152

Boiler13CyclesHigh16

30153

Boiler13CyclesLow16

30154

Boiler14CyclesHigh16

30155

Boiler14CyclesLow16

30156

Boiler15CyclesHigh16

30157

Boiler15CyclesLow16

30158

Boiler16CyclesHigh16

30159

Boiler16CyclesLow16

Figure 43 MODBUS — BoilerStatus Flags

Bit

Description

Valid Values/Range

0

Pilot Valve

0 = closed, 1 = open

1

Blower Running

0 = off, 1 = running

2

Ignition Alarm

0 = ok, 1 = alarm

3

Valve Alarm

0 = ok, 1 = alarm

4

High Limit

0 = ok, 1 = tripped

5

Air Prove Switch

0 = open, 1 = closed

6

RESERVED (FACTORY)

7

Software Operator

0 = off, 1 = on

8

Header Sensor not Detected

0 = detected, 1 = not detected

9

Supply Sensor not Detected

0 = detected, 1 = not detected

10

Return Sensor not Detected

0 = detected, 1 = not detected

11

Outside Sensor not Detected

0 = detected, 1 = not detected

12

System Pump

0 = off, 1 = on

13

Combustion Air Damper

0 = off, 1 = on

14

Master Boiler

0 = member, 1 = master

15

Boiler Detected (at this address)

0 = not detected, 1 = detected

Name

Description Valid Values/Range

Page 66

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 44 MODBUS — BoilerStatus2 Flags

Bit

Description

Valid Values/Range

0

Disabled

0 = enabled, 1 = disabled

1

Heat Demand

0 = no demand, 1 = demand (1)

2

Alarm

0 = ok, 1 = alarm

3

Failed

0 = ok, 1 = failed

4

Member Error

0 = ok, 1 = error

5

Boiler Running

0 = off, 1 = running

6

Pump Running

0 = off, 1 = running

7

Spare 3 Interlock

0 = open, 1 = closed

8

LWCO Interlock

0 = open, 1 = closed

9

VFD Interlock

0 = open, 1 = closed

10

Gas Prove Interlock

0 = open, 1 = closed

11

Spare 4 Interlock

0 = open, 1 = closed

12

Operator Interlock

0 = open, 1 = closed

13

Water Prove (Flow) Interlock

0 = open, 1 = closed

14

UV Sensor Air Prove Interlock

0 = open, 1 = closed

15

Main Valve

0 = closed, 1 = open

Figure 45 MODBUS — BoilerStatus3 Flags

Bit

Bit

Bit

0

AA High Fire

0 = off, 1 = on

2

4-20ma Remote Enable

0 = off, 1 = on

3

Outdoor Air Reset Override

0 = off, 1 = on

4

T1

0 = off, 1 = on

5

T2

0 = off, 1 = on

6

T3

0 = off, 1 = on

7

T4

0 = off, 1 = on

8

reserved for future use

---

9

reserved for future use

---

10

reserved for future use

---

11

reserved for future use

---

This BoilerStatus2 Heat Demand Flag is a combination of the Heat Demand input and the Modbus Heat Demand (40001).

1 Heat Demand (Local Override) 0 = off, 1 = on (1)

Page 67

MODBUS COMMUNICATIONS HeatNet Control V3 1.x

Figure 45 MODBUS — BoilerStatus3 Flags

Bit

Bit

Bit

12

reserved for future use

---

13

reserved for future use

---

14

reserved for future use

---

15

reserved for future use

---

This BoilerStatus3 Heat Demand Flag is Heat Demand input. On member boilers, this indicates a “Local Override”.

Page 68

TROUBLESHOOTING HeatNet Control V3 1.x

Troubleshooting

This section is included as an aide to help troubleshoot
problems with the setup and operation of the boiler. See

Appendix A for additional fault messages.

Situation:
Nothing happens when the power switch is turned
on.

1. If the Ignition Control is active, but the front panel

display is inactive check:

a. Cable and cable polarity from the control board to

the display.

b. J14 on control board. The transformer supplies

24vac to power the control.

c. Check for 120vac on the primary of the

transformer and 24vac on the secondary. If one of
the 24vac interlocks has been shorted to ground or
the 24vac output is low, the transformer may be
damaged or a 24vac circuit may be miss-wired.

The H-Net control is equipped with resettable

fuses on the power input circuit. Wiring
power incorrectly to the unit will cause these
fuses to open. Once the incorrect wiring is
corrected, the fuses should reset themselves in
less than 5 minutes.

Situation:
You get the error message for the Combustion Air
Damper.

1. The prove switch for the combustion air damper is not

closing. Check to make sure the dampers are being
controlled by the output relay. Also check to make sure
the prove switch is wired and working properly.

2. If (1.) has been done and you are using SPARE 1 and

you continue to get the error message, check the sensor
TYPE specified for sensor #5 in the sensors menu. If it
is set to NONE the controller will not recognize the
closed circuit. Set the Sensor #5 to ON/OFF.

Situation:
The display is displaying random characters or the
control keeps resetting.

There may exist a grounding problem with the controller or
one of the boilers, pumps, contactors or other devices
connected to it. If all grounding is correct, there may be an
issue with radiated or induced electrical noise (interference).
This may be caused by, arcing across a contactor's contacts
when starting a pump motor, or a large electrical load. It
may also be caused by, the ignition transformer being
improperly grounded, or the spark gap set incorrectly.

1. Attempt to identify the noise source:

2. What is the boiler/controller trying to do at the time of

the failure?

3. Is the boiler on the same circuit as the noise source?

(the boiler should have isolated power.)

4. Are shielded sensor wires used? (Ensure the shields are

grounded only at the boiler control end.)

5. Are any sensors or sensor wires located near a

transmitting antenna? (Move sensor)

Situation:
There are no heating boilers on.

1. Check the settings for WWS SETPOINT, WARM

WEATHER SHUTDOWN; if the outdoor air
temperature is above the WWS SETPOINT and
WARM WEATHER SHUTDOWN is set to YES, the
circulator pump relay will be locked out and the heating
boilers will not fire.

2. If the water temperature is within the heating band

around the setpoint, boilers will not come on. The water
temperature must fall below the lower band limit to
begin firing boilers.

Situation:
Unable to change the # of Boilers in the BOILERS
menu.

1.

In H-Net method, the KN-Series control auto-detects
the boilers in the system and adjusts the # of boilers
accordingly.

3. If you are not using the combustion air damper then it

needs to be disabled in the AUX FUNCTIONS menu.

2. Using H-NET, if the # of Boilers is not being adjusted

properly to the actual amount of boilers in the system,
check each boiler. There can only be (1) master boiler,
but there can be up to 15 member boilers. Currently, a
total of 16 boilers in a system.

Page 69

TROUBLESHOOTING HeatNet Control V3 1.x

Situation:
The boilers menu only indicates 1 boiler, but there
are member boilers connected and the amber light
blinks on all of the boilers communication’s jacks.

1. Ensure that the latest version of firmware is installed on

all boilers. All boilers in a system must have the same
firmware revision.

2. Ensure the proper termination is set on the Master and

the last Member boiler.

Situation:
You get the error message – WATER FLOW
SWITCH or WAITING FOR FLOW.

1. If the control does not sense a closed circuit at input

connection, WTR FLW. Check to make sure the circuit
for the circulator pump is correct, that the pump is
being energized, and that the flow prove switch is
working properly.

2. If there is no flow prove switch, check to make sure that

a jumper wire has been hooked up to J11B, WTR FLW
interlock.

d. Minimize the electrical interference by routing the

communications cable away from electrical noise
sources, such as: Motors, ignition controls,

contactors etc…

Situation:
Only the MASTER boiler Fires, but the system has
many boilers and is using H-Net.

1. In order for the MASTER boiler to act as a MASTER,

the header sensor must be set to TYPEZ, and there must
be a header sensor present. At power-up, the header
sensor is auto detected. If the temperature of the header

sensor at power-up is greater than –25 F and less than

240 F it is considered a valid sensor. The boiler will
default to the MEMBER mode if the temperature is not
in this range and can only be run locally or by external
inputs.

a. If the LOAD FACTORY DEFAULTS has been

used to restore all the default settings, the header
sensor has been set to NONE. This needs to be set
as stated in 1, and the header sensor will need to be
replaced or the temperature brought into a valid
range. A power cycle of the boiler will detect the
sensor if it is in the range as stated in 1.).

Situation:
H-Net boilers are detected but then lost and then
detected again etc...

1. The H-Net communications cable may be receiving

interference from the blower, ignition, or other form of
radiated electrical noise. Termination of the jumpers
may not be correct or there is more than one master.

a. Ensure that the termination jumpers are set on the

MASTER boiler and only the LAST MEMBER
boiler. All of the other member boilers should have
their termination jumpers in the non-terminated
position.

b. There may be (2) or more MASTER boilers.

Ensure that only one header sensor is present and
connected to the SYS/DHW input. There should be
no wires or sensors connected to the SYS/DHW
input if the boiler is operating as a member. This
input is auto detected and defines the boiler as a
MASTER.

c. Ensure the cable to connect the H-Net is of a

shielded or twisted pair type. Shielding of the cable
is required.

b. The H-Net needs a communications cable daisy-

chained between boilers. Ensure that a good
connection is made on the communications board
and that the lights on the dual RJ45 jack flash
(roughly twice a second). The MASTER is the only
one that should flash with no communications

cables plugged in.

Situation:
I am in CALIBRATE and I cannot fire the boiler to
adjust it.

1. Only one, but any one of the T1-T2 inputs can be used

to start the boiler. All other inputs are disabled. This
method prevents an external control or Building
Management System from trying to control the boiler
while it is offline and being calibrated. If the boiler is
being used as a staged boiler controlled by an external
control, the staged inputs need to be disconnected
before CALIBRATION, since more than one of the T
inputs may be closed by the external control.

Page 70

TROUBLESHOOTING HeatNet Control V3 1.x

Situation:
You have forgotten the password.

2. As a last resort, you can turn the controller off, then

depress and hold the ESC key while turning it back on.

This will load the default password “AAAAAA”.

Situation:
Firmware update program starts to load, but then
stops, or does not load at all.

1. Check that the termination shunts J3 and J6 are not in

the termination setting. If they are, remove them
temporarily while updating. Restore them for proper
communication with a building management system.

2. Ensure that the USB driver for your PC/Laptop

computer is properly installed.

3. Disconnect BMS or Protocessor Module if connected.

Situation:
All HeatNet Boilers fire at the same time.

1. This is usually caused by the HeatNet addresses on the

Member boilers not being set. If the address on each
boiler is not set, then all boilers will have address = 2
by default. When the Master boiler calls to fire boiler
#2, all boilers with address #2 will fire. Set each
Member boiler to a unique address from 2-16.

2. Check the ADD Boiler delay time to ensure it is at a

reasonable value. A setting of 0 will start all the boilers
at the same time.

the firing rate is changing, but the display
indicates it is running at the same modulation rate.

1. The Boiler always shows it’s called for firing

modulation %. This is not an indication of what the
boiler is actually firing at. In this case, the boiler is
trying to meet the called for modulation % which is
displayed, but is unable to do so. The boiler protects

itself by looking at it’s supply water temperature and

the temperature is probably in the Operating Limit
Band. While in the operating limit band, the HeatNet
control limits the input of the boiler. The boiler tries to
deliver the most input it can in an attempt to meet the
called for modulation % without tripping the operating
limit.

2. If the boiler is constantly varying in blower speed and

in the operating limit band there may be not enough
flow through the boiler or the Operating
Limit/Operating Limit Band may be improperly set.
The Operating Limit/Operating Limit Band should not
overlap the heating band. This may occur when a
building management system is controlling the setpoint
and is setting the setpoint in the operating limit band.

3. Example: Setpoint set to 180F (by Building

Management) and the Operating Limit is set to 200F
with a 20F Operating Limit Band. When the boiler is

trying to deliver 180F to the load it’s supply

temperature would be a minimum of 180F. The
beginning of the Operating Limit Band (looks at supply
temp) would be 200F-20F = 180F. Now, when the
Master is trying to maintain setpoint at 180F, the boiler
is trying to reduce input beginning at 180F at its supply
sensor and as a result, fighting the setpoint. The
Operating Limit band needs to be reduced in this case,
while taking into account the Heat Band differential.

Situation:
The boiler is showing that it is running at 45% and
there is no fire in the sight glass.

1. The Boiler always shows it’s called for firing

modulation %. This is not an indication of what the
boiler is actually firing at. If the ignition control fails to
receive a call to fire (last interlock closed on terminal 6
of the ignition control) the display will indicate the
called for %. Check if the ignition control is in standby,
if so then the HeatNet control has closed the Start
contact on J5.10 (Limits) and is waiting for the Blower
relay to close on the ignition control which is monitored
on J5.3 of the HeatNet control.

Situation:
I can hear the blower ramping up and down and

Situation:
The Master boiler sees all of the Member boilers in
the system, but does not fire any of the Members.

1. If the Master modulates to 100% without firing a

Member boiler and the Member boilers are seen by the
Master (in menu SETUP:BOILERS), then the Member
boilers are sending back offline status to the Master.

a. The Member boilers may have an alarm or error

condition which would be indicated by a blinking
boiler # in the Boilers Firing screen.

b. Ensure the HeatNet is set up properly: Amber

lights blink on HeatNet Jacks. Only one Master
boiler.

Page 71

TROUBLESHOOTING HeatNet Control V3 1.x

c. If the Member boiler is in Local Mode then it also

would not be called and report unavailable to the
Master.

d. If the Local flow switch for the Local pump is

wired to the System flow switch input this would
also create an offline condition. The Member needs
to detect system flow or have a jumper across that
sensor input in order for the Member boiler to
report available status. The Local flow prove
switch must be wired to the Water Flow interlock
sensor input.

Situation:
We are using a BACnet or LonWorks bridge. We
can talk to the bridge, but all of the data is zero (0)
or invalid.

This condition usually indicates that the bridge is not
communicating with the HeatNet control. When operating
properly, the bridge continuously reads data from the boiler
on the Modbus port into an internal buffer. When a BACnet
or LonWorks read request is received, the buffered values
are placed in a BACnet or LonWorks packet and sent. If the
bridge has never been able to successfully read data from
the control, all data points will have their default value
which is typically zero. In this situation, the control will also
not respond to write commands; for instance changing the
setpoint.

1. The control’s MODBUS ADDRESS must be set to one

(1). This is set in the ADVANCED SETUP-
>DISTRIBUTED CONTROL menu. On older

(legacy) firmware this setting was also called the

CONSOLE ADDRESS.

2. The control’ BAUD (rate) must be set to 19200 and the

DATA FORMAT must be set to 8E1 (8 data bits, even

parity, 1 stop bit). On older (legacy) versions of

firmware, the DATA FORMAT was called PARITY
which must be set to EVEN. These settings are set in
the ADVANCED SETUP->COMMUNICATIONS

menu.

3. Check the termination on the BMS/Modbus port. If the

control is the first or last device on the Modbus RTU
network, it should be terminated. For the short cable
runs (for instance when using a BACnet or LonWorks
bridge on a Revision 1.x board), the termination should

be in, but usually doesn’t matter.

4. Check the wiring. The Modbus RTU (RS485)

connections on the HeatNet control are A(+), B(-), and
G (ground). Some systems use opposite polarity; A(-),
B(+). Always use the polarity to determine the proper

connections. A ground wire must always be used

and a shielded twisted wire is STRONGLY
suggested.

5. The HeatNet LonWorks and BACnet bridges plug

directly into Revision 2.x+ boards. Legacy boards
(Revision 1.x) required a ProtoCarrier to provide power
and the RS485 signal conversion to the bridge. The
RS845 signal conversion chips are easily damaged by
electrical noise, ground loops, and large differences in
ground potential between devices on the network. This
is a common problem faced by all RS485 devices, not
just the HeatNet control. To help eliminate grounding
problems, nylon standoffs are required to isolate the
bridge from the boiler chassis. The ProtoCarrier should
also be powered from the 24VDC output on the
HeatNet control to help eliminate electrical noise (VFD
and spark pickup, power spikes, etc.) on the power
supply lines. Please download complete HeatNet
bridge installation instructions from the product web
site.

a.

When the ProtoCarrier is functional, the small

green surface mount TX and RX LEDs near the 6­pin connector (power and communications) should
be flashing regularly.

b. If the TX LED flashes very briefly about once per

minute, the ProtoCarrier has most likely been
damaged, please contact Tech Services.

c. If either LED is always on, the ProtoCarrier has

most likely been damaged, please contact Tech
Services.

Situation:
We are using a Building Management System
(BMS) to control the boilers. We can write the
setpoints, but they keep changing back to their
“default” values after approximately 60 seconds.

1. When using a BMS, the setpoint values work in

conjunction with the SETPOINT TIMER. The
SETPOINT TIMER is a failsafe feature used to help

detect that a BMS is no longer working or
communicating with the control. The time must be
regularly loaded with a predetermined number of

seconds (1 – 65535). Every second this value will

decremented. If it reaches zero, the local (permanently
saved) values for the setpoints will be loaded. The
concept is that periodically (or every time a setpoint is
written), the BMS must write this value. If the value
reaches zero (0), the HeatNet control assumes that the

BMS in no longer functional and “safe” operational

values for the setpoints will be restored. As an
example, if it is decided that the BMS will write the
control every 5 minutes, you may decide to write 600

Page 72

TROUBLESHOOTING HeatNet Control V3 1.x

seconds (10 minutes) to the setpoint timer. If after 10
minutes (5 minutes longer than the normal write
interval) the BMS has not written the timer, the saved
setpoint values will be restored.

2. As a convenience, the SETPOINT TIMER is

automatically loaded with 60 seconds (if it has fallen
below 60) each time the setpoint is written. If you
decide to take advantage of this convenience, you
would need to write the setpoint periodically at less
than 1 minute intervals.

3. Newer firmware versions allow the SETPOINT

TIMER failsafe feature to be disabled by writing a zero

(0) to the timer. The feature will automatically revert
back to the enabled state whenever the control is reset

or power cycled. The SETPOINT TIMER failsafe

feature can permanently disabled (or enabled) in

firmware versions 3.35 or greater. This setting can be
changed in the ADVANCED SETUP-
>COMMUNICATIONS menu.

Page 73

OPERATION HeatNet Control V3 1.x

KN HeatNet Control Run Screen

Hold theBACK

button down
for 5 seconds

to enter the

SETUP menus

MASTER:SYSTEM SET
MEMBER: LOCAL SET
SYSTEM SET

RUN %100

RUN %100

RUN %100

RUN %100

RUN %100

SYSTEM SET

158°F

HEADER

142°F

SUPPLY

162°F

OUTSIDE

50°F

RETURN

90°F

Press the UP or DOWN Arrow Keys
to navigate the display screen.

RUN %100

LOCAL SET

158°F

The SETPOINT can be adjusted by
pressing and holding the SELECT
button until the SETPOINT flashes.
Then use the UP and DOWN buttons
to change the value. Pressing the
SELECT button saves the value.

CALIBRATE

RUN %100

MIN VFD

CALIBRATE

25%

RUN %100

IGN VFD

CALIBRATE

30%

If the Header Sensor is present the
menu will display SYSTEM SET,
otherwise it will display LOCAL SET.

The BLRS FIRING screen is used by the Master
boiler to indicate which boilers are firing. If the
boiler # is blinking a problem exists on that boiler.
To the far right the current active system pump is
displayed vertically as P1 or P2 (Pump 1 or Pump 2)

RUN %100 *STATUS

START 0
STOP 0

RUN %100

RUN %100

BLRS FIRING

1_2______P
_________2

DELTA TEMP

25°F 25°F

RUN %100

DHW TEMP

157°F

RUN %100

DHW SETPT

160°F

RUN %100

RUN %100

SYS RETRN

NA

RUN %100

RUN %100

RUN %100

RUN %100

RUN %100

RUN %100

RUN %100

MAX VFD

CALIBRATE

90%

CALIBRATE

DELTA TEMP

CALIBRATE

DHW TEMP

CALIBRATE

157°F

DHW SETPT

CALIBRATE

160°F

CALIBRATE

SYS RETRN

CALIBRATE

NA

RUN %100

TACH

5853

RUN %100

TACH

CALIBRATE

5853

Page 74

OPERATION HeatNet Control V3 1.x

KN HeatNet V3 Control Menu Tree — Advanced Thermal Hydronics

HOME SCREEN

RUN %100

KN30 V1 .07

BO

ILE

SE

TPO

OU

TDO

RS

INT

OR

SYSTEM SET

140°F

S
AIR

RE

SET

Press and HOLD BACK

button down for 5

seconds to enter the

menu screen

#

LEAD BOI L ER #

HEAT

HNT

OF

ILERS

BO 1

BAND

12

40 °F

0

MAIN MENU SCREEN

SE
AD
VI

TUP

VAN
E

SE

CED

W

LOG

TUP

ADVANCED MENUS

1
H
O

2:4
2O
A

M

6:0

7
NA

---

02/

7

3P

F

°

---

SE

M

PS

O

20

T

%

D

M

PB

PUMP
NIGHT
OPT I O

LOG / RUN T I ME

LOG/RUNTIME
AUX
DOMESTIC HOT WATER
SYSTEM

T I ME

DAY

M

ON

DAY
YEA

1

160

4

- R

OPT

SE TB ACK

NS

FUNCT

OF

T

H

R

3

°

F
0

M

I

ONS

CLOCK

W

E

IONS

EK

:92

5A

TUE

E

S

2
1

20

LOCAL
OPERATE
OPL
S ETPT SOURCE

L

SYSTEM PUMP
LOCAL PUMP

PUMP/VALVE OPTION

FLOW PROVE:

SETBACK

IGHT

N

SCALE

TEMP

KEY

I

CL

CK

PASSWORD

SKIP

RI

B

GHTNESS

RUN HOURS

DATA LOG ENTRY
BOILER CYCLES

COMBUST AIR

ARM SILE

AL

M

P
7

2

FAILSAFE MODES

HEAT EXCHANGER

DHW BOILER?

DHW SETPOINT

DHW DIFF

USE SENSOR?
DHW PRIORITY?

POST PURGE
DHW MASTER? NO

SIZE

DAMPER

NCE

10s

ON

ON

50%

160°F

5°F

120S

F

NO

NO
NO

SET

L IM

IM BAND

OA

RESET

WARM WEATHER SD:
WWS SETPOINT

SET OA

W

ATE

R T
AT

H

IGH

OA

N

EXT

W

ATE

R T
AT

W

O

OA

B

AC K

POST PRGE TIME 5m
PUMP ROTATION

SUMMER PUMP JOG:OFF

OVR ENAB IN WWS: OFF

DELTA

DELTA

POST

ALWAYS

N

MASTER PUMP/VALVE

REMAINS ON: OFF

LOCAL PUMP VFD: OFF

TYPE : L INKED COMMON

IN USE?
INPUT: J12B PIN 7

PROOF T IME

160

2

AUTO

SET POINTS

EMP

140

70

M

TE

P

EMP

180

M

10

T

E

P

TEMP

ENAB

TEMP

PRGE

TIM

ENABLED

F

°

0

0

F

°

0

°

2

F

OFF
OFF

68°F

F

°
°

F
F

°

F

°

ROTAT ION: NONE
SYS TEM PUMPS:
ROTATE T IME

MORE MENUS

OFF

10

5m

E

OFF

YES

2:00

ZERO RUNT IME

°

PUMP1 TIME
PUMP2 TIME

ALWAYS ENABLED OFF

:

96HR

PUMP 1

112HR
250HR

2

Page 75

OPERATION HeatNet Control V3 1.x

_____

_

_

_

_

_

_

_

_

_

_

/

/

///

KN HeatNet V3 Control Advanced Menu Tree — Advanced Thermal Hydronics

H-

TER

DELAY

DELAY

LAST

OUTS IDE

OAD

SSW

-

-

-

TIONS

L?

SET?

NET

YES

255

TIME
FIRE

TRUE

10 HRs

0m

YES

95

10mins

NONE

0- 10V

NO

R

NO

NO

0s

1

ADD DELAY TIME

4 MINUTES

0 SECONDS

SHED DELAY TIME

2 MINUTES

0 SECONDS

MODULATE DELAY TIME

0 MINUTES

10 SECONDS

STOP MOD MAX

% 70

START PRIORITY 1
SET: FIRST
STOP PRIORITY 1
SET: LAST

PLACE
1K

OR
CHANNEL

ON

TRIM

OHMS

TRIM

4mA SETPOINT
20mA SETPOINT
BOILER START

PRIORITY

INTRLK ASSIGNMENTS

SYSTEM FLOW: ON

LOAD F IRMWARE
SOURCE

A

PREC

1OK

VALUE

I

SI

I

RES

I

STOR

#

_

_

_

=

SET!

NORMAL

USB DRIVE

ON

__

68°F

200°F

4.11mA

ACCELERATE

DECELERATE
SOFT START SECS :

3.0%/S

2.0%/S

DI STRI BUTED

MODULAR BO ILER SET

ADAPTIVE MOD

MODE

MODE

DEFAULTS

DEFAULTS

2

F IR ING

FIRING

BASE LOADING

SENSORS
4-20mA INPUT

PASSWORD

COMMUNICATIONS
LOAD

BLOWER SETT I NGS

COMMUNICATIONS

LOAD

BLOWER SETT I NGS

SYSTEM

CTRL

C

ONTROL

H-

NET

MAS

H-NET ADDRESS

MODBUS ADDRESS

ADD BOILER

SHED BOILER
MODULATE
MOD

MOD MODE: ADAPTIVE

DROP DOWN: ON PILOT

DELAY RELEASE :

MODE
MIN RUNTIME:
MIN OFFTIME

MORE MENUS

FIRING PRIORITY : 2

PREDICT START:

BASE LOAD BOILERS: 0
START > MOD
STOP FIRST
DELAY TIME

SENSOR

SENSOR #

TYPE

CAL I

ANALOG IN CHANNEL :1

CHANNEL MODE:

CLG

A

H

O

D

N

E

W

C

OMMUNICA
BAUD 19200
DATA FORMAT 8E1

SETPOINT TIMER ON

FACT

FACT

DELAY

-

MAX

ASS IGNMENTS

E

BRA

TE?

E

N

P

:

---

-

-

:

-

---

CA

ORY
ORY

RE

CONFIGURE I NTERLKS

LOAD F I RMWARE
OPTION: NO OPTION

BOI LER TYPE

PRODUCT:

CONDENSING YES

BTU IN 2000,000

MORE MENUS

BLOWER:

MASS MEDIUM

TURNDOWN

ALTITUDE:

KN30

AMETEK

5 :1

< 2000FT

Page 76

WORKSHEET HeatNet Control V3 REV 1.x

SETUP MENU

BOILERS

# of BOILERS

LEAD STAGE

HEAT BAND °

SETPOINTS

LOCAL SETPOINT

°

OPERATE LIMIT °

OP LIM BAND

°

SETPOINT SOURCE

OUTDOOR AIR RESET

°

OA RESET

WARM WEATHER SD

WWS SETPOINT °

SET OA SETPOINTS

WATER TEMP

°

@

HIGH OA TEMP

°

WATER TEMP

°

@

LOW OA TEMP

°

PUMP OPTIONS

SYSTEM PUMP

POST PURGE TIME

PUMP ROTATION

ROTATION:

SYSTEM PUMPS:

ROTATE TIME:

MORE MENUS

ZERO RUNTIME PUMP

PUMP1 TIME

PUMP2 TIME

ALWAYS ENABLED

SUMMER PUMP JOG

OVR ENAB IN WWS

LOCAL PUMP

DELTA TEMP ENAB

DELTA TEMP °

POST PRGE TIME

s

ALWAYS ENABLED

PUMP/VALVE OPTION

Worksheet

Page 77

WORKSHEET HeatNet Control V3 REV 1.x

REMAINS ON:

LOCAL PUMP VFD

FLOW PROVE

NIGHT SETBACK

SETBACK ENTRY

1 2 3

4

ENTRY IS

SETBACK ° ° ° °

SETBACK TIME

START DAY

TIME

END DAY

TIME

OPTIONS

TEMP SCALE °

KEY CLICK

SKIP PASSWORD

BRIGHTNESS %

LOG/ RUNTIME

RUN HOURS

DATA LOG ENTRY

SIZE

BOILER CYCLES

AUX FUNCTIONS

COMBUST AIR DAMPER

TYPE:

IN USE?

INPUT:

PROOF TIME

ALARM SILENCE SWITCH

IN USE

INPUT:

FAILSAFE MODES

H-NET COMM LOST

LOW TEMP:

TEMP <

HEAT EXCHANGER

EXCHGR DELTA T

LIMIT-> HALF RATE

DOMESTIC HOT WATER

DHW BOILER?

DHW SETPOINT

DHW DIFF

USE SENSOR?

Page 78

WORKSHEET HeatNet Control V3 REV 1.x

DHW PRIORITY?

POST PURGE

DHW MASTER?

SYSTEM CLOCK

ADVANCED SETUP

DISTRIBUTED CTRL

CONTROL

H-Net MASTER

H-NET ADDRESS

MODBUS ADDRESS

MODULAR BOILER SET

ADD BOILER DELAY

SHED BOILER DELAY

MODULATE DELAY TIME

MOD MAX – LAST FIRE

%

ADAPTIVE MOD

MOD MODE:

DROP DOWN

DELAY RELEASE

FIRING MODE

MODE

MIXED
START PRIORITY 1

SET:

STOP PRIORITY 1

SET:

MIN RUNTIME

MIN OFF TIME

PREDICT START

BASE LOADING

BASE LOAD BOILERS:

START > MOD

STOP

DELAY TIME

SENSORS

SENSOR #

OUTDSIDE

SUPPLY

RETURN

HEADER

DHW

6 7 8

TYPE

4-20mA INPUT

ANALOG IN CHANNEL:

CHANNEL MODE:

4mA SETPOINT

20mA SETPOINT

BOILER START

Page 79

WORKSHEET HeatNet Control V3 REV 1.x

PRIORITY

PASSWORD

COMMUNICATIONS

BAUD

DATA FORMAT

SETPOINT TIMER

BLOWER SETTINGS (AMETEK BLOWER)

ACCELERATE

DECELERATE

SOFT START SECS:

SYSTEM

CONFIGURE INTERLKS

INTRLK ASSIGNMENTS

SYSTEM FLOW… ON

LOAD FIRMWARE

Version:

OPTION:

BOILER TYPE

FIRING PRIORITY

BTU IN

CONDENSING

MASS

MIN VFD

IGN VFD

MAX VFD

CALIBRATION SETTINGS

Page 80

HeatNet Control REV 3.47-1

Thermistor Resistance/Temperature Table

Temp qC Temp qF

-40 -40 336,450 60 140 2,488

-35 -31 242,660 65 149 2,083

-30 -22 176,960 70 158 1,752

-25 -13 130,410 75 167 1,479

-20 -4 97,072 80 176 1,255

-15 5 72,951 85 185 1,070

-10 14 55,326 90 194 915.4

-5 23 43,326 95 203 786.6

0 32 32,650 100 212 678.6

5 41 25,391 105 221 587.6

10 50 19,899 110 230 510.6

Resistance

Temp qC Temp qF

Resistance

15 59 15,711 115 239 445.2

20 68 12,492 120 248 389.6

25 77 10,000 125 257 341.9

30 86 8,057 130 266 301.0

35 95 6,531 135 275 265.8

40 104 5,326 140 284 235.4

45 113 4,368 145 293 209.0

50 122 3,602 150 302 186.1

55 131 2,986

Page 81

HeatNet Control REV 3.47-1

This screen indicates that the boiler’s SUPPLY

Temperature has gone above the OPERATOR
LIMIT. This will mainly be seen on member
boilers to show why they are not available to fire.

This screen indicates that the boiler’s SUPPLY

temperature has risen inside the OPERATOR LIMIT
BAND.

This screen indicates the boiler’s input is being

limited by the MOD-MAX value to optimize system
efficiency. This will only be seen on a

MASTER

boiler.

* Status Information

Whenever an * is displayed on the RUN screen it indicates that there is more information available about the current running
conditions. This information can be viewed by going to the *STATUS screen as shown on the previous page. For more

information on the parameters discussed here please see the Default Settings & Menu Item Descriptions — SETUP, starting on

page 52.

Status information screens

Page 82

HeatNet Control REV 3.47-1

This screen indicates the control is attempting to re

­initiate the ignition control because the ignition
control did not begin PRE

-PURGE. For more

information see CALL SERVICE LOG entry.

This screen indicates that the boiler’s has rec

eived a

heat demand, but it’s MINIMUM OFF time has not

expired.

This Screen indicates that the boiler’s input is
temporarily being limited to optimize the boiler’s

efficiency.

This screen indicates that the boiler is running in
LOCAL MODE because it

has lost H-NET
communications with the MASTER, and the failsafe
mode has been activated.

Status information screens

Page 83

HeatNet Control REV 3.47-1

Status Screen Fault Display

There are numerous interlock switches and software
limits that are detected. Each of these, when tripped will
produce a display message, an audible beeping, and an
alarm relay closure. The fault is displayed first, then after
a second, the time the fault occurred is displayed. This
cycle will keep occurring until the fault is cleared.

These faults and interlocks are:

HIGH LIMIT:

When the high limit aquastat trips the following message
is displayed:

LOW WATER CUTOFF:

If there is a low water condition reported by the low water
cutoff switch this fault is displayed. Check that there is water
flow and water in the boiler. There is a reset switch located on
the LWCO box. The interlock connection is located on J5B,
LWCO.

VAR FREQ DRIVE:

The variable frequency drive, which controls a non Ametek
blower, if supported, reports this fault. It may be caused in the
event of over current or an internal VFD fault that would
cause it to shut down. If this is the case, check the fault
indicators on the VFD. The interlock is located on J5B, VFD.

The high limit interlock breaks power to the ignition
control (shutting it off) and effectively removes any
chance of the gas valve receiving power. The HeatNet
series control will remain powered to display the fault,
latch the alarm relay/audible beeper, and to access the log.
The interlock is located on J5, HIGH LIMIT. Ensure
power is present on the input to the High Limit Control.

SPARE 4:

This is a reserved interlock input that is user defined. The
interlock is located on J5B, SPARE 4.

DELTA TEMPERATURE WARNING:

If the temperature difference across the boiler measured
from RETURN water to SUPPLY water exceeds the
EXCHR DELTA T RANGE, setting this message will be
displayed.

GAS PRESSURE:

The gas pressure switches (high pressure and low pressure) are
connected in series, so if either trip, a fault will be reported
here. A reset switch is located on the gas pressure switches.
The interlock is located on J15B, GAS PR.

SYSTEM WATER FLOW:

Once the HeatNet series boiler receives a call for heat, it
closes the system circulator pump relay. It then waits 10
seconds or more (adjustable) to prove flow. If there is no flow,
the flow switch alarm will be set. Every 10 seconds the
circulator pump relay will cycle ON for 10 seconds and then
OFF for 10 seconds to try and establish flow. The interlock
connection is located on J5B, SYSTEM WTR FLOW.

Page 84

APPENDIX A HeatNet Control REV 3.47-1

OPEN ******* SENSOR :

If the open sensor fault is displayed, the sensor in the position
reported was originally detected, but has since opened. The
boiler will shut down on any OPEN sensor except the
OUSTSIDE AIR sensor.

WTR FLW LOCAL:

Once the HeatNet series boiler receives a call for heat, it
closes the LOCAL PUMP/VALVE relay. It then waits 10
seconds or more (adjustable) to prove flow. If there is no
flow, the flow switch alarm will be set. Every 10 seconds
the circulator pump relay will cycle ON for 10 seconds
and then OFF for 10 seconds to try and establish flow.
The interlock connection is located on J5B, WTR FLW.

SHORTED ******* SENSOR:

If the shorted sensor fault is displayed, the sensor in the
position reported was originally detected, but has since
shorted. The boiler will shut down on any SHORTED sensor
except the OUSTSIDE AIR sensor.

IGNITION CTRL ALARM:

The ignition control alarm is displayed if the ignition
control detects a fault. This could be a flame failure, air
proving switch, or other fault associated with the ignition
control. When this fault occurs, you will need to refer to
the ignition control for the reason.

COMBUST AIR DAMPER:

If the combustion air damper has been selected for use
(AUX FUNCTIONS), and the proof switch does not
make, this fault will be displayed.

When the master boiler receives a call for heat and needs
to start a boiler, the DAMPER relay closes on J13. If the
combustion air damper does not prove within the proof
time specified in the combustion air damper menu, the
boiler will not start and then display the fault. A
combustion damper fault on a boiler can only be cleared
by power cycling.

AIR SWITCH:

If the IGNITION control closes its blower relay, the control
does not see the PILOT relay close within (2) minutes, and the
AIR PRESSURE switch is made, this message will be
displayed. This alarm protects the boiler from freeze ups being
caused by a blower bringing in cold outside air with no fire.

CALL SERVICE:

If the H-Net control closes the last interlock string entering the
ignition control and the ignition control never closes its
Blower Relay, the H-Net control will wait 2 minutes. The H­Net control will then retry for the duration of the local pump
post purge time and then retry the ignition sequence. During

this time “retry strt” will be displayed in the status screen.

After (5) attempts the H-Net control will lock out and display
call service.

Page 85

APPENDIX A HeatNet Control REV 3.47-1

DELTA TEMPERATURE WARNING:

If the temperature difference across the boiler and
measured from RETURN water to SUPPLY water

exceeds “EXCHGR DELTA” this message will be

displayed. This can be set to an alarm condition in the
AUX FUNCTIONS menu. High delta temperatures can
result in damage to the boiler.

BLOWER, RPM HIGH: (Ametek Blower)

If the signal from the HeatNet control board to the
Ametek blower goes above the factory limits or the

blower “runs away” (excessive speed), this message will

be displayed. With this event, the HeatNet control will
lockout the boiler and the boiler will require a manual

reset to restart. Operation of the blower above the boiler’s

maximum blower rpm setting could over fire the boiler.

FAULT

TACH

BLOWER, RPM HIGH
HIGH FIRE

0

Page 86

APPENDIX B HeatNet Control REV 1.x

Line # 4 Message

Description

SETBACK IS ACTIVE

If any of the (4) temperature setbacks are active these log entries will be
displayed in the log.

NO LOCAL FLOW
NO SYSTEM FLOW

If the test for flow fails these log entries will be displayed. The flow proving
switches are wired to J11A

and J11B.

COMBUSTION AIR FAIL

If the combustion air damper is used and does not prove across J10B
DAMPER or J12B DAMPER, this message is displayed.

SYSTEM RESET

O: stack overflow,
U: Stack Underflow ( both are software faults)

R: Reset Instruction ( Firmware or Default load),

W: Watchdog ( Firmware code ran erroneous code and
rebooted),
P: Power

B: Brown
VDC)

When the control is reset, this log entry captures the reason the reset occurred.

OUTDOOR RESET

This log entry indicates that Warm Weather Shutdown is in effect.

Line 4 Log Entries:

The following table lists the messages on line # 4 of the log’s display.

SETBACK EXPIRED

-- ----

-ON (Power switch toggled),

-out ( Microcontroller saw a voltage less than 4.5

Page 87

APPENDIX B HeatNet Control REV 1.x

Line # 4 Message

Description

HIGH DELTA TEMP

This log entry occurs when the temperature across the heat exchanger has
been greater

SHUTDOWN UV TEST

After 24 hours of continuous runtime the ignition control module needs to

check it’s UV detection circuit. An orderly shutdown and then a restart will

occur. This log entry indicates that this

has taken place. This is not a fault.

HIGH LIMIT EXCEEDED

If the mechanical aguastat trips due to it’s high temperature setting having

been exceeded, this log entry will occur.

IGNITION CTRL ALARM

The ignition control module has faulted while performing an ignition
sequence, or while monitoring flame during normal operation.

IRI Alarm

If the gas valve proving circuit ( if equipped) detects a gas pressure problem.

DOMESTIC HOT WATER

Indicates a call for DHW heating by either the DHW se
thermostat.

LOW WATER CUTOFF
VAR FREQ DRIVE
GAS PRESSURE
SPARE 4
OP LIMIT MECH

These log entry faults are result of the interlocks connected to the 24VAC
interlock inputs: J11A and J11B.
Low Water Cutoff = Low water condition in
Var Freq Drive = The blowers Variable Frequency Drive has a problem
Spare 4 = User installed interlock,
Op Lim Mech = An external operator (aquastat).

START FAILED, RETRY

If the H

-Net control closes the last interlock string entering the ignition

control and the ignition control never closes its Blower Relay, the H

-Net
control will wait 2 minutes. The H-Net control will then retry for the duration
of the local pump post purge time and then retry the ignition sequence. During

this time “retry strt” will be displayed in the status screen. After (5) attempts

the H

-Net control will lock out and display call service. The Log will report

the retries.

OP LIMIT REMOTE

The is the firmware Operating Limit as defined in
SETUP:SETPOINTS:OPERATE LIM. When the Supply temperature exceeds
this value, this event is logged.

OPEN OUTSIDE SENSOR,
SUPPLY SENSOR,
RETURN SENSOR,
HEADER SENSOR,
DHW SENSOR

If one of the 10k thermistor sensors was detected to be open or not connected,
this fault will be

SHORTED OUTSIDE SENSOR,
SUPPLY SENSOR,
RETURN SENSOR,

If one of the 10k thermistor sensors was detected to be shorted this fault will
be logged.

than the EXCHR DELTA T RANGE degrees F.

nsor or an external

logged.

boiler

Page 88

APPENDIX B HeatNet Control REV 1.x

Line # 4 Message

Description

HEADER SENSOR,
DHW SENSOR

AIR SWITCH(BLOWER)

If a call is made to the ignition control to start and the HeatNet control detects
a blower start, but no Pilot within two minutes, the boiler locks out. This log
entry indicates that the blower was ON with no flame in the boiler. Freeze up
protection.

LOST BOILER #
FOUND BOILER #

These log entries indicate that HeatNet has either discovered a boiler or lost a

boiler using it’s au to detection algorithm.

FAIL SAFE H
FAIL SAFE LOW TEMP

If the Fail Safe modes are active, these log entries indicate that they became
active for some reason and the boiler had entered Fail Safe mode.

BASE LOAD BOILER

The Base load Boiler Relay K8 is Active if ON
Inactive if OFF

CALL SERVICE

If the H
control and the ignition control never closes its Blower Relay, the H
control will wait 2 minutes. The H-Net control will then retry for the duration
of the local pump post purge time and then retry the ignition sequence. During

this time “retry strt” will be displayed in the status screen. After (5) attempts

the H
BLOWER, RPM HIGH

The tachometer feedback from the blower indicated that it was above the
maximum speed allowed for the boiler. Only used with Ametek blowers.

-NET LOST

-Net control closes the last interlock string connected to the ignition

-Net control will lock out and display call service.

-Net

Page 89

IN UNITED STATES: 260 NORTH ELM ST.s WESTFIELD-!ssF!8

IN CANADA: 7555 42!.-%2%$2)6%s-)33)33AUGA, ONT.,3,ssF!8

www.knseries.com