AERCO BMS 168 User Manual

Boiler Management

System

Installation

Instructions

Boiler Management

System

Operation &

Troubleshooting

DISPLAY MODE

HDR

TEMP

AIR

TEMP

%

LOAD

FOR USE W/ INDOOR TEMP. SENS.

SET

POINT

OFF
SET

PROP
BAND

CONFG

SYS

Hold Key for

Display Header

Header Set

Temp., oF

Display Outside Air
Temp., oF

Display % Load &
No. of Units Operating

Display/Change Indoor
Sensor Reference Temp.,

Display/Change Setpoint
Temp when Activated

Display/Change
Hdr. Temp. / Indoor Ref. Temp.

System
Configuration

o

F

FIELD ADJUSTMENT MODE

FIELD

L.E.D. "On"
Enables Field Adjustment

ADJ

Select System Start Option

SYS

Display/Change Outside Air

START

Temp. for System Start

TEMP

Display/Change
Bldg Ref Temp — Indoor/Outdoor

REF

TEMP

Hdr Set Temp — Constant Set

HDR

Display/Change

TEMP

Minimum Or Maximum

LIMIT

Header Temp.
Display/Change

RESET

Header Temp. / Outside Air Temp.

RATIO

(Alarm Cancel) Reset Alarm Contact

%

Set Date

LOAD

And Time

Set Up

OFF

Set Back

SET

Clock
Select Fault

CONFG

Alarm Relay

SYS

Options

Enable BMS

ON

Disable BMS

OFF

Reset Mode
Point Mode

Raise/Lower

To Change

HEADER SET INDOOR AIR

DISPLAY

ADJ

HDR

TEMP

TEMP

SYS

REF

START

TEMP

LEVEL

PROP

SET

BAND

POINT

OFF
SET

ON OFF

CONFIG

AERCO INTERNATIONAL INC., NORTHVALE, N.J.

AIR

SYS

HDR
TEMP
LIMIT

RESET
RATIO

%

LOAD

FIELD

ADJ

Applicable to Serial Numbers 329985 and above
(EPROM Rev. K and above)

AERCO International, Inc.

AERCO International, Inc.

159 Paris Avenue

159 Paris Avenue
Northvale, NJ 07647-0128

Northvale, NJ 07647-0128

GF-108M

REVISED 3/13/08

Telephone Support

Direct to AERCO Technical Support
(8 to 5 pm EST, Monday through Friday):

1-800-526-0288

AERCO International, Inc.
159 Paris Avenue
Northvale, NJ 07647-0128

www.aerco,com

© AERCO International, Inc., 2008

The information contained in this
installation, operation and mainte­nance manual is subject to
change without notice from
AERCO International, Inc.

AERCO makes no warranty of any
kind with respect to this material,
including but not limited to implied
warranties of merchantability and
fitness for a particular application.
AERCO International is not liable
for errors appearing in this
manual. Nor for incidental or
consequential damages occurring
in connection with the furnishing,
performance, or use of this
material.

Table of Contents

Page

SECTION 1 ABOUT YOUR NEW BOILER MANAGEMENT
SYSTEM (BMS) 1-1

SECTION 2 FEATURES OF THE BMS 2-1

SECTION 3 INSTALLING THE BMS 3-1

3.1 MOUNTING THE BMS 3-1

3.2 GENERAL WIRING 3-1

3.3 PULSE WIDTH MODULATION WIRING 3=2

3.3.1 PWM Wiring at BMS 3-2

3.3.2 PWM Wiring at Boilers 3-2

3.4 RS485 (MODBUS) WIRING 3-2

3.4.1 RS485 Wiring at BMS 3-2

3.4.2 RS485 Wiring at Boilers 3-3

3.5 SENSOR INSTALLATION AND WIRING 3-3

3.5.1 Header Sensor 3-3

3.5.2 Outside Air Sensor 3-3

3.6 INTERLOCK WIRING 3-4

3.6.1 Interlock 1 Wiring 3-4

3.6.2 Interlock 2 Wiring 3-4

3.7 RELAY WIRING 3-4

3.7.1 System Start Relay 3-4

3.7.2 Fault Alarm Relay 3-4

3.7.3 Auxiliary Relay 3-4

3.8 SET BACK 3-4

SECTION 4 FAMILIARIZING YOURSELF WITH THE BMS 4-1

4.1 ABOUT BMS MODES 4-1

4.1.1 Selecting and Viewing Functions 4-1

4.1.2 Changing Function Settings 4-1

4.2 NORMAL MODE FUNCTIONS 4-4

4.2.1 HDR TEMP 4-4

4.2.2 AIR TEMP 4-4

4.2.3 % LOAD 4-4

4.2.4 SYS START TEMP 4-4

4.2.5 REF TEMP 4-4

4.2.6 HDR TEMP LIMIT 4-4

4.2.7 FIELD ADJ 4-4

4.2.8 SET POINT 4-4

4.2.9 PROP BAND 4-4

4.2.10 OFF SET 4-4

4.2.11 RESET RATIO 4-4

4.2.12 ▲ and ▼ Arrow Keys 4-5

i

Table of Contents

(Continued)

4.2.13 ON and OFF Keys 4-5

4.2.14 CONFIG SYS 4-5

4.3 FIELD ADJUST MODE FUNCTIONS 4-5

4.3.1 HDR TEMP 4-5

4.3.2 AIR TEMP 4-6

4.3.3 % LOAD 4-6

4.3.4 Setting the Internal Clock With the % LOAD Key 4-6

4.3.5 SYS START TEMP 4-7

4.3.6 REF TEMP 4-7

4.3.7 HDR TEMP LIMIT 4-7

4.3.8 FIELD ADJ 4-8

4.3.9 SET POINT 4-8

4.3.10 PROP BAND 4-8

4.3.11 OFFSET 4-8

4.3.12 Setting Up a Reset Schedule 4-8

4.3.13 Manual Set Back 4-9

4.3.14 RESET RATIO 4-9

4.3.15 ▲ and ▼ Arrow Keys 4-9

4.3.16 ON and OFF Keys 4-9

4.3.17 CONFIG SYS 4-9

4.4 SYSTEM CONFIGURATION MODE FUNCTIONS 4-10

4.4.1 TEMP FAIL MODE 4-10

4.4.2 SYS ENABLE 4-11

4.4.3 MAX PWR INPUT 4-11

4.4.4 START AND STOP LEVEL Keys 4-12

4.4.5 BLR OP MODE 4-12

4.4.5.1 Sequential Mode 4-12

4.4.5.2 Parallel Mode 4-13

4.4.5.3 Combination Mode 4-13

4.4.5.4 Designating the Number of Combination Boilers 4-13

4.4.6 HDR SET MODE 4-13

4.4.7 INTGL RATE GAIN and DERIV GAIN Keys 4-13

4.4.7.1 TEMP BANDWIDTH 4-14

4.4.7.2 INTGL RATE GAIN 4-14

4.4.7.3 DERIV GAIN 4-14

4.4.8 AUX RELAY 4-15

4.4.9 ▲ and ▼ Arrow Keys 4-15

4.4.10 ON and OFF Keys 4-15

4.4.11 CONFIG SYS 4-15

ii

Table of Contents

(Continued)

SECTION 5 PROGRAMMING THE BMS MODE OF OPERAT

5.1 INDOOR/OUTDOOR RESET MODE 5-1

5.1.1 Selecting Indoor/Outdoor Reset Mode 5-1

5.1.2 Entering System Start Temperature 5-1

5.1.3 Determining the Reset Schedule 5-1

5.1.4 Entering the Building Reference Temperature 5-2

5.1.5 Entering the Reset Ratio 5-2

5.2 SETUP FOR REMOTE SETPOINT MODE 5-2

5.2.1 Entering Header Set and Boiler Operating Modes 5-2

5.2.2 Entering Remote Signal Type and Header Temperature Limits 5-2

5.3 SETUP FOR CONSTANT SETPOINT MODE 5-3

5.3.1 Entering Header Set and Boiler Operating Mode 5-3

5.3.2 Entering Header Reference Temperature 5-3

5.4 CONFIGURING BOILERS FOR PULSE WIDTH MODULATION (PWM) 5-3

5.4.1 C-More Control System PWM Setup 5-4

5.4.2 Configuring the Temperature Controller 5-4

5.5 SYSTEM INITIALIZATION AND POLLING 5-4

5.6 TESTING THE SYSTEM 5-5

ION

APPENDICES

Appendix A Specifications A-1
Appendix B Methods for Determining Reset Schedule
and Indoor/Outdoor Reset Ratio Charts B-1
Appendix C Normal (Read-Only) Mode Display Messages
and Defaults C-1
Appendix D Field Adjust Mode Display Messages and Defaults D-1
Appendix E Config Sys Mode Display Messages and Defaults E-1
Appendix F Sensor Resistance Data Sheet F-1
Appendix G Parts List G-1
Appendix H Troubleshooting H-1
Appendix I General BMS Wiring I-1
Appendix J Programming the BMS Using RS-232 Communication J-1

iii

List of Figures

Figure 1 Typical BMS Installation 3-5
Figure 2 BMS Mounting 3-6
Figure 3 Wire Routing Locations at the BMS 3-7
Figure 4 PWM Communication Outputs at the BMS 3-8
Figure 5 Pulse Width Modulation Connections at KC Series Boiler
Boiler With Modular Control Box 3-9
Figure 6 PWM & RS485 Connections at KC Series Boiler
With C-More Control Box 3-10
Figure 7 Pulse Width Modulation Connections at the Benchmark
Boiler With Modular Control Box 3-11
Figure 8 PWM & RS485 Connections at the Benchmark
Boiler With C-More Control Box 3-12
Figure 9 BMS RS485 & RS232 Connector Locations 3-13
Figure 10 BMS RS485 & RS232 Connector Pin Assignments 3-14
Figure 11 Header Sensor Installation With Well 3-15
Figure 12 Outside Air Sensor Mounting and Connections 3-16
Figure 13 Normal and Field Adjust Mode Overlay 4-2
Figure 14 System Configuration Mode Overlay 4-3

iv

Section 1 ______________________________

SIMPLE INSTALLATION AND

About Your
New Boiler
Management
System (BMS)

AERCO’s Boiler Management System
(BMS), stages and modulates AERCO KC
Series and Benchmark Boilers, allowing
them to operate efficiently as a system. It
provides a broad array of operating modes,
so that the nuances of specific applications
can be easily accommodated. The BMS can
control up to 40 boilers; 8 via pulse width
modulation (PWM) and up to 32 via Modbus
(RS485) communication. For Modbus
control, the AERCO Boilers must be
equipped with C-More Control Systems.

PRECISE CONTROL

Utilizing PWM or Modbus control, the BMS
fully exploits the condensing and modulating
ability and efficiency of each boiler and
regulates the output of the boiler plant with
water supply temperature variation of no
more than ±2°F

Staging can be performed sequentially or in
parallel. The BMS can sample building
reference temperatures to modulate boiler
plant output, and will perform water supply
temperature night setback automatically
referenced to its internal clock.

OPERATION

Installation of the BMS is simple, and low­voltage wiring is employed between the
BMS panel and boiler modules. There are
no complex design steps to be performed,
since a keypad in conjunction with the LCD
allows the operator to acquire, change, and
program settings through easy-to-use
labeled buttons. Each BMS function
consists only of selecting the function and
toggling values, which generally requires no
more than pressing four keys.

The instant a parameter is programmed, it is
automatically entered into the BMS
memory, avoiding multiple programming
steps to store information. In the event of
power loss, most factory default settings
remain in nonvolatile memory for up to 10
years and need not be reprogrammed.
However, date and time remain in memory
for about 30 days.

BMS PROGRAMMING VIA
RS232 PORT

If desired, the BMS can be programmed by
connecting a Laptop Computer, or other
type of terminal emulation device, to the
RS232 connector on the left side of the
BMS. See Appendix J for programming
using RS232 communication.

1-1

Section 2 ______________________________

SEQUENTIAL OR PARALLEL

Features of

OPERATION

the BMS____

APPLICATION FLEXIBILITY

Three different system or control options
can be selected at setup to match the needs
of any closed-loop system - Indoor/Outdoor
Reset, 4-to-20 mA Remote Setpoint, and
Constant Setpoint.

CONTINUOUS
COMMUNICATIONS

The BMS continually sends information to
the boilers and receives information from
them, providing total control of boiler plant
dynamics.

EXCEPTIONAL ACCURACY

The BMS control system uses a PID
(Proportional Integral Derivative) control
algorithm to respond dynamically to system
changes. Water temperatures are precisely
controlled by modulating energy in put. A
supply water temperature of ±2°F is
assured.

BUILDING INDOOR AIR
TEMPERATURE INPUTS

The BMS accepts building indoor air
temperatures directly from a thermistor
sensor or from a 4-to-20 mA signal.
Adjustments can be made to the header
setpoint temperature to compensate for
varying building temperatures and
conditions.

Modules can be either sequenced on, or run
in parallel, by selection from the front panel.
In sequential mode, boilers are brought on
one at a time, so turn-down ratio is 14
multiplied by the number of KC Series
boilers, or 20 multiplied by the number of
Benchmark boilers. This provides higher
energy savings and seasonal efficiency. In
parallel mode, all of the boilers are
modulated together at the same firing rate.
The turn-down ratio of the system is fixed at
14:1 for the KC Series boilers and 20:1 for
the Benchmark boilers.

BUMPLESS TRANSFER

When in sequential mode, the BMS stages
boilers on and off, one at a time, at
selectable percentages of firing rate. The
result is a seamless transition and
undetectable room temperature changes.
Sequential mode has several other unique
features:

Run-Time Equalization: The BMS se-

quences boilers on a first on-first off basis,
which automatically equalizes the run time
of all boilers in the plant.

Automatic Load Distribution: The BMS

continuously monitors the number of
modules that are available for operation. In
the event of a boiler malfunction or when
service is performed, the BMS automatically
compensates for a lack of response from
any unit and brings on the next available
boiler to satisfy demand. This feature
operates in both parallel and sequential
modes.

2-1

Time Delay Between Boiler Starts:

A fixed, 30-second time delay between
boiler starts ensures smooth energy input
without spikes in electrical, gas, or venting
conditions.

AUTOMATIC SYSTEM START

Automatic system start contacts for
controlling auxiliary equipment such as
pumps and dampers can be selected to
close between 32°F and 100°F outside air
temperature, eliminating the need for the
plant operator to turn auxiliary equipment on
and off.

MINIMUM AND MAXIMUM
HEADER SET CLAMPING

The supply water temperature can be
clamped at a maximum high temperature or
minimum low temperature, to ensure that
the building temperature is optimal for the
greatest comfort.

Two Interlock Circuits
(Enable/Disable Contacts)

The BMS contains two normally-open
interlock circuits that require only a set of
dry contacts to enable or disable the boiler
plant. They can be used to monitor pumps,
combustion air dampers, or other equip­ment. Out-of-limit conditions trip the
interlocks, shutting down the boiler plant,
and providing a high level of protection.

ADJUSTABLE OFFSET

The Offset feature can allow the
temperature of the supply water to be offset
in 1° increments over a range of -50°F
below to +50°F above its current
temperature. This feature is employed for
night setback or morning warmup. The BMS
lets you select, over a 7-day period, the time
when the offset begins and ends.

CONTROL OF AUXILIARY
EQUIPMENT

The auxiliary relay uses a dry set of
contacts to operate auxiliary equipment. For
example, when the boiler plant is at 100%
load, these contacts close and can start an
auxiliary boiler, or notify an energy manage­ment system of a full-load condition.

FAULT ALARM SURVEILLANCE

The BMS continually monitors its sensors
for opens and shorts and the interlock
circuits for opens. However, the BMS fault
alarm relay does not close or indicate a fault
when a boiler has failed. The fault alarm
circuit consists of a dry set of 120 VAC
contacts rated at 5 A.

SIMPLE INSTALLATION

The BMS operates from 120 VAC, 50 to 60
Hz, and uses Belden 9841 or equivalent
wiring between modules for control and
monitoring. The lightweight panel can be
mounted up to 200 feet from the boilers
when using pulse width modulation
communication.

RUGGED AND RELIABLE

The BMS is housed in a NEMA 13-grade
enclosure and operates in ambient tempera­tures as high as 131°F (55°C).

POWER-OFF MEMORY

Most system configuration values are
retained in nonvolatile memory for up to 10
years. Date and time remain in memory for
approximately 30 days.

MODBUS COMMUNICATION

The BMS can monitor or control C-More
Boilers using Modbus communication via its
RS485 port. It can also be monitored or
controlled by a Building Automation System
(BAS) or a PC connected to its RS232 port.

2-2

Section 3 ______________________________

3.2 GENERAL WIRING

Installing the
BMS________

Please follow the installation procedure in
the order presented. Incorrect wiring may
damage the unit and void the AERCO
warranty Do not omit steps, and do not
substitute other types of wiring for those
specified. Figure 1 shows a typical BMS
installation.

3.1 MOUNTING THE BMS

Use the mounting plate (Figure 2) supplied
with the BMS to securely mount the unit
away from moisture, and at an appropriate
height for easy reading of the display. To
reduce the possibility of electrical noise
entering the system, mount the BMS at
least 6 feet away from electrical devices
such as power panels, high voltage
transformers and transmission lines,
motors, and fluorescent lights.

All wiring and fusing must be in compliance
with the National Electrical Code and with
local electrical codes. Control wiring for the
sensors and communications links must run
in separate conduit and not in the conduit
providing line voltage in order to ensure
immunity from electrical noise.

All wiring should be installed in conduit
leading up to the bottom of the BMS panel.
There are five knock-outs in the bottom of
the panel by which wiring must enter the
BMS.

Shielded, twisted-pair cable should be used
for sensor and communication wiring. This
wiring should be 18 to 24 AWG. Examples
of suitable sensor and communication wire
are: Belden 9841, 8761, 3105A or equiv­alent. AC power wiring should be 16 to 18
AWG. A BMS wiring diagram is included in
Appendix I. Once mounting is complete and
the BMS is secured in place, loosen the two
captive screws on the wiring cover plate
with a Phillips screwdriver. Feed all wiring
through the knock-outs provided on the
bottom of the panel. All pulse width
modulation (PWM) and RS485 control wires
should be fed through the two knock-outs
furthest to the left.

Shock Hazard!

Extreme caution must be exercised
when connecting power wiring to
the BMS. The external circuit
breaker supplying Line voltage to
the the BMS must be turned off to
avoid electrical shock

Power wiring should be fed through the
right-most knock-out in the bottom of the
panel (Figure 3). The remaining knockouts
are for control wiring located on the middle
terminal block. The terminal blocks can be
detached from the BMS headers to simplify
field wiring.

Once power wiring is completed, apply line
voltage to the BMS, and press the ON key
on the BMS keypad to verify proper
connection. The display should show
INITIALIZING EPROM REV. n where n is
the current EPROM version.

3-1

WARNING!

Turn off AC input power to the BMS
to avoid electrical shock.

3.3 PULSE WIDTH
MODULATION WIRING

Pulse width modulation (PWM) wiring
connections are made between the BMS
JP2 terminal block and the Relay or I/O Box
terminals at each AERCO Boiler. Shielded
twisted-pair wire is recommended.

3.3.1 PWM Wiring At BMS

To wire boilers for pulse width modulation
(PWM), connect the boiler control wires in
ascending order according to the numbers
on the BMS (Figure 4). For example, the
control wiring for boiler 1 at the BMS would
be connected as follows:

• Positive control wire connects to JP 2,
terminal 1 (+).

• Negative control wire connects to JP 2,
terminal 2 (-).

• Shield wiring connects to the negative (-)
control wire at Section BLR 1, terminal 2.
The shield is not terminated at the boiler.
All shields must be terminated on the
BMS end. The wiring terminals labeled
SHIELD at terminal block JP3 of the
BMS are not internally connected to
ground and are only used as a place to
terminate the sensor shields. The pulse
width modulation shield can be
connected to any minus (-) terminal of
the PWM terminal strip (JP2).

3.3.2 PWM Wiring At The Boilers

The pulse-width modulation (PWM) control
wiring from the BMS to each boiler is
connected at each boiler’s relay box or
input/output (I/O) box, depending on the
type of control system used. Modular control
systems utilize a relay box as shown in
Figure 5 (KC1000) and Figure 7
(Benchmark). The newer C-More control
system utilizes an I/O box as shown in
Figure 6 and Figure 8.

Regardless of the type of control system
used, the PWM wiring is connected to the
BMS + and – terminals as shown in the
respective illustrations. It is imperative that
positive (+) and negative (-) polarity be
observed when making these connections.
All boilers follow the same control wiring
scheme.

When using pulse width modulation, the
BMS may be mounted up to 200 feet from
the boilers.

3.4 RS485 (MODBUS) WIRING

All Modbus Networks are implemented
using a “Master - Slave” technique. The
BMS can function as either a “Master”
controlling C-More Slaves or a “Slave”
controlled by a “Master” Energy
Management System (EMS) or Building
Automation System (BAS). Therefore, the
following paragraphs provide only an over­view of the required wiring connections.
Detailed information and setup procedures
for RS485 Modbus networks are provided in
Modbus Communication Manual GF-114.
Refer to GF-114 prior to implementing any
RS485 networks using Modbus.

RS485 wiring connections are made using a
“Daisy-Chain” configuration. Shielded
twisted-pair wire from 18 to 24 AWG is
required for all RS485 wiring.

3.4.1 RS485 Wiring At BMS

RS485 wiring connections are made at the
BMS at connector JP11 which is labeled
RS485 TO BLRS. The location of this
RS485 connector is shown in Figure 9. In
addition, Figure 9 also shows the locations
of the external and internal RS232
connectors which are used to interface the
BMS to an EMS Master if required. The pin
assignments for the RS485 and RS232
connectors are shown in Figure 10.

3-2

Connect the RS485 wiring at the BMS as
follows:

• Connect the positive (+) lead to the +(B)
terminal of JP11.

• Connect the negative (-) lead to the -(A)
terminal of JP11.

• Connect the shield to the SHLD terminal
of JP11.

3.4.2 RS485 Wiring At Boilers

RS485 wiring connections are made at the
RS485 COMM terminals of each boiler’s I/O
Box as shown in Figures 6 (KC1000) and
Figure 8 (Benchmark). Connect the wiring
as follows:

• Connect the positive lead to the +
terminal

• Connect the negative lead to the ­terminal

• DO NOT terminate the shields to the
Ground (G) terminal at the Boiler end of
the RS485 loop. Connect the shields of
the incoming and outgoing leads
together. The RS485 loop should only be
terminated at the BMS.

RS485 loops should not exceed 4000 feet.

Detailed wiring diagrams for RS485 Modbus
communication networks are provided in the
Modbus Communication Manual GF-114.

3.5 SENSOR INSTALLATION

AND

There are two types of sensors that may be
installed -- header sensors and outside air
sensors. While an outside air sensor is
required for Indoor/Outdoor Reset mode, it
is not required for Constant Setpoint or 4-to­20-mA modes of operation. However, it is
recommended to take full advantage of all
BMS features. The header sensor is
required for all modes of operation.

Sensor wiring and power wiring should be
run separately to reduce the chance of
electrical noise entering the sensor wiring.

WIRING

3.5.1 Header Sensor

The header sensor to be used with the BMS
is a sensor that requires a well as shown in
Figure 11. When installing the sensor, use a
1/2 inch NPT tapped coupling or a 4 x 4 x
1/2 Tee fitting. Use heat-conductive grease
when installing to aid in its response. The
sensor probe must be inserted at least 2
inches into the flow of water for proper
response. The header sensor must be
installed between 2 and 10 feet downstream
of the LAST boiler in the plant’s supply
water header.

The header sensor is a thermistor type
sensor. The Resistance vs. Temperature
Chart for the sensor is provided in Appendix
F. See Figure 11 for installation details.

Shielded pair 18 AWG cable (Belden # 8760
or equiv.) is recommended for header
sensor wiring. There is no polarity to be
observed. Connect the wires from the
sensor to BMS terminals 4 and 5 on JP3.
The ground for the shield is at BMS end of
the link, not the header sensor. Connect the
ground to JP3, terminal 8 (SHIELD). The
header sensor can be installed up to 600
feet from the BMS.

3.5.2 Outside Air Sensor

The Outside Air Sensor, AERCO part no.
122662, must be mounted on the North side
of the building, shielded from direct sunlight,
and away from air intakes or outlets from
the building. See Figure 12 for a typical
installation. The sensor includes a plate for
wall mounting. Shielded pair 18 AWG cable
(Belden # 8760 or equiv.) is recommended
for sensor wiring. There is no polarity to be
observed. Connect the sensor wires to BMS
terminals 1 and 2 on JP3. Connect the
shield to JP3, terminal 3 (SHIELD) at the
BMS. The shield must not be grounded on
the sensor end. The sensor can be mounted
up to 600 feet from the BMS.

3-3

3.6 INTERLOCK WIRING

The BMS is equipped with two interlocks
designated Interlock 1 (INT 1) and Interlock
2 (INT 2). Since both interlocks must be
closed for the BMS to operate the boiler
plant, the associated wiring terminals are
jumpered, prior to shipment. If desired,
proving device switches can be connected
to either
used, interlock wiring connections are made
as described in the following paragraphs.

3.6.1 Interlock 1 Wiring

Interlock 1 is often used with auxiliary
equipment, such as air dampers or flow
switches. If used, connect the end proving
switch to INT 1 terminals 11 and 12 as
shown in the wiring diagram in Appendix I.

3.6.2 Interlock 2 Wiring

Interlock 2 is a general purpose interlock
which can be used with a variety of devices
or equipment or conditions that must be
proved prior to enabling the boiler plant. If
used, connect the end proving switch to INT
2 terminals 13 and 14 as shown in the
wiring diagram in Appendix I.

interlock in place of the jumper. If

NOTE

If necessary, Interlock 1 can be
programmed to operate the boilers
only when the outside air
temperature falls below the system
start temperature. See para. 4.4.2
for details. Interlock 2 cannot
programmed with this feature.

be

3.7 RELAY WIRING

The BMS contains a System Start Relay, a
Fault Alarm Relay and an Auxiliary Relay
which can be connected to external
monitoring or control devices. The contacts
for each of these relays are rated at 120
VAC, 5A and are fused internally at 5A with
replaceable fuses. The contact terminals
for these relays are shown in the wiring
diagram in Appendix I.

3.7 1 System Start Relay

The state of the System Start (SYS START)
relay contacts are controlled by the value
set for the SYS START TEMP function in
the Field Adjust Mode (para. 4.3.5). The
contacts are closed only when the outside
air temperature is less than the System
Start Temperature (SYS START TEMP)
which is set in the Field Adjust Mode. The
default for this temperature setting is 70°F.

3.7.2 Fault Alarm Relay

The state of the Fault Alarm (FLT ALARM)
relay contacts are controlled by the option
selected by pressing the CONFIG SYS key
when in the Field Adjust mode (para.

4.3.16). Contact closure can be set to ALL
FAULTS, INTERLOCK 1, INTERLOCK 2, or
NO INTERLOCK.

3.7.3 Auxiliary Relay

The state of the Auxiliary (AUX) relay
contacts are controlled by the AUX RELAY
CLOSE option selected when in the System
Configuration mode (para. 4.4.8). Contact
closure can be set to occur either when all
available boilers are at the maximum power
input or no boilers are available (all boilers
faulted or turned off).

NOTE

The SET BACK function is used only
if the header supply temperature will
be offset manually as described in
para. 4.3.13. Disregard para. 3.8 if
an automatic header temperature
reset schedule is used as described
in para. 4.3.12.

3.8 SET BACK

The SET BACK terminals shown in the
wiring diagram in Appendix I are used only
when implementing a manually-controlled
header temperature offset. If used, connect
a dry contact switch across SET BACK
terminals 15 and 16 on JP3.

3-4 3-5

Figure 2

BMS MOUNTING

3-6

Figure 3

RECOMMENDED WIRE ROUTING LOCATIONS AT THE BMS

3-7

Figure 4

PWM COMMUNICATION OUTPUTS AT THE BMS

3-8

Figure 5

PULSE WIDTH MODULATION CONNECTIONS AT

KC SERIES BOILER WITH MODULAR CONTROL BOX

3-9

Remove sheet
metal cover to
access I/O Box

OUTDOOR SENSOR IN

SENSOR COMMON

AUX SENSOR IN

NOT USED

ANALOG IN

B.M.S. (PWM) IN

SHIELD

mA OUT

RS-485
COMM.

NOT USED

REMOTE INTL'K IN

EXHAUST SWITCH IN

DELAYED INTL'K IN

NOT USED

NC

FAULT RELAY

COM

120 VAC, 5A, RES

+

­+

-

+

-

+

G

-

NO

NC

AUX RELAY

COM
NO

120 VAC, 5A, RES

NOT USED

PWM Connections

RS485 COMM Connections

Figure 6

PWM & RS485 CONNECTIONS AT

KC SERIES BOILER WITH C-MORE CONTROL BOX

3-10

Figure 7

PWM CONNECTIONS AT

BENCHMARK BOILER WITH MODULAR CONTROL BOX

3-11

Open Door To
Access I/O Box

OUTDOOR SENSOR IN

SENSOR COMMON

AUX SENSOR IN

NOT USED

ANALOG IN

B.M.S. (PWM) IN

SHIELD

mA OUT

RS-485
COMM.

NOT USED

REMOTE INTL'K IN

EXHAUST SWITCH IN

DELAYED INTL'K IN

NOT USED

NC

FAULT RELAY

COM

120 VAC, 5A, RES

+

­+

-

+

­+

G

-

NO

NC

AUX RELAY

COM
NO

120 VAC, 5A, RES

NOT USED

PWM Connections

RS485 COMM Connections

Figure 8

PWM & RS485 CONNECTIONS AT

BENCHMARK BOILER WITH C-MORE CONTROL BOX

3-12

Figure 9

BMS RS485 & RS232 CONNECTOR LOCATIONS

3-13

Figure 10

BMS RS485 & RS232 CONNECTOR PIN ASSIGNMENTS

3-14

1/2 “ NPT

Figure 11

HEADER SENSOR INSTALLATION WITH WELL

3-15

Figure 12

OUTSIDE AIR SENSOR MOUNTING AND CONNECTIONS

3-16