AERCO BMS II BOILER User Manual
GF-124
Instruction
No
AERCO INTERNATIONAL, Inc., Northvale, New Jersey, 07647 USA
.
Installation, Operation
& Maintenance Instructions
BMS II BOILER
MANAGEMENT
SYSTEM
JANUARY 19, 2011
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., 2011
The information contained in this installation,
operation and mainte nance manual is s ubject to
change without notice from AERCO
International, Inc.
AERCO makes no warranty of any kind with
respect to this material, inc luding but not limited
to implied warranties of merchantability and
fitness for a particular application. AERCO
International is not liable for er rors appearing in
this manual. Nor for incide ntal or consequential
damages occurring in connection with the
furnishing, perform ance, or use of this material.
FOREWORD
Phrase, Abbreviation or
A (Amp)
Ampere
ADDR
Address
ALRM
Alarm
AUX
Auxiliary
below)
Baud Rate
Symbol rate, or simply the number of distinct symbol changes (signaling
each symbol is 1 bit long.
BCM
Boiler Control Module used with AERCO Modulex Series Boilers
BLR
Boiler
BMS II
AERCO Boiler Management System, Second Generation
BND
Band
Bias Resistors
A pair of resistors used to force the communication line to a definite logic
state so that noise is not picked up as invalid data during communication.
BLDG (Bldg)
Building
C-More Controller
(or Control Box)
A control system developed by AERCO and currently used in all Benchmark
and KC1000 Series product lines.
CNTL
Control
DIP
Dual In-Line Package
DYN
Dynamic
EMS
Energy Management System; often used interchangeabl y with BAS
Ethernet
A computer networking technology for Local Area Networks (LANs)
FDX
Full-Duplex
FLT
Fault
GND
Ground
HDR
Header
HDX
Half-Duplex
Foreword
The Model 5R5-384 B oiler Management S ystem II (BMS II) is the l atest model of AERCO’s BMS lin e of
flexible boiler plant contr ollers.. The system can control a boil er plant comprised of AERCO Benc hmark
Series, Modulex Series or KC10 00 Boilers. The BMS II can stage an d coordinate the operation of up to
32 AERCO Boilers with maximized efficiency. With individual boilers with turn-down ratios as high as
20:1, a 5-boiler plant can deli ver a system turn-down ratio of 100: 1 when the bo il e r s ar e s taged to opera te
sequentially.
The BMS II is fully compatible with a wide array of Building Automation Systems (BAS) or Energy
Management System s (EMS) utilizing M odbus Pr otocol. T he BAS or EMS com municates with the BMS II
utilizing a RS232 i nterfac e. If the BAS or EMS does not c ontain a RS23 2 port , the BMS II can be order ed
with a RS485-to-RS232 Converter which can be easily installed within the BMS II’ wiring compartment.
PHRASES, ABBREVIATIONS & ACRONYMS
The phrases, abbreviations and acronyms used in this document are listed in the following table
Phrases, Abbreviations and Acronyms
Acronym
BAS Building Automation System, often used interchangeably with EMS (see
events) transmitted per second. It is not equal to bits per second, unless
Meaning
i
FOREWORD
Hex
Hexadecimal Number (0 - 9, A - F)
Hz
Hertz (Cycles Per Second)
INTLK
Interlock
I/O
Input/Output
I/O Box
Input/Output (I/O) Box currently used on all Benchmark and KC Series
products
IP
Internet Protocol
ISO
Isolated
LSB
Least Significant Byte
LSD
Least Significant Digit
MA (mA)
Milliampere
MAX (Max)
Maximum
MIN (Min)
Minimum
Modbus®
A serial, half-duplex data transmission protocol developed by AEG Modicon
MSB
Most Significant Byte
MSD
Most Significan t Digit
MS/TP
Master-Slave/Token-Passing (usually over RS485 networks)
OFFS
Offset
OUTD
Outdoor
PTP
Point-to-Point (usually over RS232 networks)
REF (Ref)
Reference
Response Time
The maximum amount of time allowed to receive a response to a request
(or EIA-232)
RS232 Standard
RS422
(or EIA-422)
A standard for serial, full-duplex (FDX) transmission of data based on the
RS422 Standard
(or EIA-485)
RS485 Standard
RTN
Return
RTU
Remote Terminal Unit
SEN
Sensor
SETPT (Setpt)
Setpoint Temperature
SHLD (Shld)
Shield
SLTA
Serial LonTalk Adapter
SYS
System
TEMP (Temp)
Temperature
Terminating Resistor
A resistor placed at each end of a daisy-chain or multi-drop network in order
to prevent reflections that may cause invalid data in the communication
VAC
Volts, Alternating Current
VDC
Volts, Direct Current
VFD
Vacuum Fluorescent Display
Phrases, Abbreviations and Acronyms - Continued
Phrase, Abbreviation or
Acronym
Meaning
RS232
RS485
A standard for serial, full-duplex (FDX) transmission of data based on the
A standard for serial, half-duplex (HDX) transmission of data based on the
ii
CONTENTS
GF-124 – BMS II BOILER MANAGEMENT SYSTE M
Operating & Maintenance Instructions
TABLE OF CONTENTS
CHAPTER 1 - GENERAL INFORMATION .................................................................................................... 1-1
1.1 SAFETY PRECAUTIONS & WARNINGS ................................................................................................... 1-1
1.2 INTRODUCTION ........................................................................................................................................... 1-1
1.3 BMS II GENERAL description ....................................................................................................................... 1-1
1.4 BMS II FEATURES ........................................................................................................................................ 1-2
Simplified Installation and Set-Up .................................................................................................................... 1-2
User-Friendly Control System Interface ............................................................................................................ 1-2
Retention of Menu Option Settings ................................................................................................................... 1-3
Application Flexibility ....................................................................................................................................... 1-3
Sequential or Parallel Operation ........................................................................................................................ 1-3
Accuracy ............................................................................................................................................................ 1-3
Bumpless Transfer ............................................................................................................................................. 1-3
Fault Alarm Surveillance ................................................................................................................................... 1-3
BMS II Programming Via RS232 Port. ............................................................................................................. 1-3
CHAPTER 2 - INSTALLATION ...................................................................................................................... 2-1
2.1 INTRODUCTION ........................................................................................................................................... 2-1
2.2 SITE SELECTION AND MOUNTING .......................................................................................................... 2-1
Mounting the BMS ............................................................................................................................................ 2-1
2.3 GENERAL WIRING REQUIREMENTS ....................................................................................................... 2-2
2.4 POWER WIRING ........................................................................................................................................... 2-3
2.5 SENSOR INSTALLATION AND WIRING ................................................................................................... 2-5
Header Sensor .................................................................................................................................................... 2-5
Return Sensor .................................................................................................................................................... 2-5
Outdoor Air Sensor ............................................................................................................................................ 2-6
2.6 RS485 (MODBUS) WIRING AT THE BMS II .............................................................................................. 2-8
BMS II Bias Switches & Loop Te rmination Resistors ...................................................................................... 2-8
2.7 RS485 (MODBUS) WIRING, BIAS & TERMINATION AT AERCO BOILERS ........................................ 2-9
RS485 Wiring, Termination& Bias for Benchmark Series and KC1000 Boilers .............................................. 2-9
RS485 Wiring for Modulex Series Boilers ...................................................................................................... 2-15
2.8 SAMPLE RS485 (MODBUS) NETWORK DIAGRAMS ............................................................................ 2-15
2.9 RS232 WIRING AT THE BMS II ................................................................................................................ 2-17
2.10 INTERLOCK WIRING ............................................................................................................................... 2-18
Interlock 1 (INT 1) Wiring .............................................................................................................................. 2-18
Interlock 2 (INT 2) Wiring .............................................................................................................................. 2-18
2.11 SET BACK WIRING .................................................................................................................................. 2-18
2.12 RELAY WIRING ........................................................................................................................................ 2-18
System Start Relay ........................................................................................................................................... 2-19
Fault Alarm Relay ........................................................................................................................................... 2-19
Auxiliary Relay................................................................................................................................................ 2-19
2.13 4 – 20 mA WIRING .................................................................................................................................... 2-19
CHAPTER 3 - OPERATION ............................................................................................................................. 3-1
3.1 INTRODUCTION ........................................................................................................................................... 3-1
3.2 FRONT PANEL OPERATING CONTROLS AND DISPLAYS ................................................................... 3-1
3.3 BMS II MENU STRUCTURE ........................................................................................................................ 3-3
Menu Processing Procedure .............................................................................................................................. 3-3
3.4 OPERATING MENU ...................................................................................................................................... 3-5
HEADER TEMP and PERCENT OF LOAD .................................................................................................... 3-5
HEADER SETPOINT ....................................................................................................................................... 3-5
OUTSIDE AIR TEMP ....................................................................................................................................... 3-5
I/O STATUS ...................................................................................................................................................... 3-6
RETURN TEMP ................................................................................................................................................ 3-6
iii
CONTENTS
TABLE OF CONTENTS (cont.)
3.5 SETUP MENU ................................................................................................................................................ 3-6
ENTER PASSWORD ........................................................................................................................................ 3-6
Date and Time Menu Options ............................................................................................................................ 3-6
3.6 RS232 MENU .................................................................................................................................................. 3-7
RS232 MODE.................................................................................................................................................... 3-7
RS232 BAUD RATE ......................................................................................................................................... 3-7
MODBUS ADDRESS ....................................................................................................................................... 3-7
NETWORK TIMEOUT .................................................................................................................................... 3-7
MODBUS PASS THRU .................................................................................................................................... 3-7
3.7 RS485 MENU .................................................................................................................................................. 3-7
RS485 BAUD RATE ......................................................................................................................................... 3-8
MIN SLAVE ADDR ......................................................................................................................................... 3-8
MAX SLAV E AD D R ........................................................................................................................................ 3-8
NUMBER NETWK BLRS ................................................................................................................................ 3-8
MODBUS CNTL TYPE .................................................................................................................................... 3-8
NETW BOILER Xx ADDRE S S = Yyy (Where Xx = 01 – 32; Yyy = 001 – 127) ............................................ 3-8
3.8 FIELD ADJUST MENU. ................................................................................................................................ 3-8
HEADER SET MODE ...................................................................................................................................... 3-8
HDR HIGH LIMIT ............................................................................................................................................ 3-8
HDR LOW LIMIT ............................................................................................................................................. 3-9
INTERNAL SETPT .......................................................................................................................................... 3-9
RESET RATIO .................................................................................................................................................. 3-9
BLDG REF TEMP ............................................................................................................................................ 3-9
REMOTE SIGNAL ........................................................................................................................................... 3-9
OFFSET ENABLE ............................................................................................................................................ 3-9
Offset Menu Options ......................................................................................................................................... 3-9
Setting Up An Offset Schedule ........................................................................................................................ 3-10
Manual Offset .................................................................................................................................................. 3-10
3.9 CONFIGURATION MENU .......................................................................................................................... 3-10
BOILER OP MODE ........................................................................................................................................ 3-10
SYS INTLK CONFIG ..................................................................................................................................... 3-11
BLR START LEVEL ...................................................................................................................................... 3-11
BLR STOP LEVEL ......................................................................................................................................... 3-11
MAX POWER INPUT .................................................................................................................................... 3-11
FAIL SAFE MODE ......................................................................................................................................... 3-11
3.10 TUNING MENU ......................................................................................................................................... 3-12
PROPORTIONAL BND ................................................................................................................................. 3-12
INTEGRAL GAIN .......................................................................................................................................... 3-12
DERIVATIVE GAIN ...................................................................................................................................... 3-13
HDR TEMP DEADBND ................................................................................................................................. 3-13
3.11 RELAY MENU ........................................................................................................................................... 3-13
SYS START TEMP ......................................................................................................................................... 3-13
SYS START OPTIO N ..................................................................................................................................... 3-13
SYS START INTLK ....................................................................................................................................... 3-13
AUX RELAY OPEN ....................................................................................................................................... 3-13
AUX RE LAY CLOSE ..................................................................................................................................... 3-13
FAULT ALRM RELAY.................................................................................................................................. 3-14
FAULT ALARM BLRS .................................................................................................................................. 3-14
FAULT ALRM CLEAR .................................................................................................................................. 3-14
3.12 CALIBRATION MENU ............................................................................................................................. 3-14
HDR SENS OFFSET ....................................................................................................................................... 3-14
OUTD SENS OFFSET .................................................................................................................................... 3-14
4 - 20 MA OFFSET ......................................................................................................................................... 3-14
RETN SENS OFFSET ..................................................................................................................................... 3-14
RAMP UP %/MIN ........................................................................................................................................... 3-15
iv
CONTENTS
TABLE OF CONTENTS (cont.)
RAMP DOWN %/MIN ................................................................................................................................... 3-15
LOAD START PCT ........................................................................................................................................ 3-15
LOAD STOP PCT ........................................................................................................................................... 3-15
RESET DEFAULTS ........................................................................................................................................ 3-15
3.13 BMS II QUICK-START GUIDE ................................................................................................................ 3-16
CONSTANT SETPT MODE (Default) ........................................................................................................... 3-16
REMOTE SETPT MODE ............................................................................................................................... 3-17
OUTDOOR RESET MODE ............................................................................................................................ 3-18
CHAPTER 4 - PROGRAMMING BMS II OPERATING MODEs .................................................................. 4-1
4.1 INTRODUCTION ........................................................................................................................................... 4-1
4.2 OUTDOOR RESET MODE ............................................................................................................................ 4-1
Selecting Outdoor Reset Mode .......................................................................................................................... 4-2
Determining Reset Schedule .............................................................................................................................. 4-2
Entering Reset Ratio and Building Reference Temperature .............................................................................. 4-2
Selecting Boiler Operating Mo de ...................................................................................................................... 4-3
Entering Boiler Start and Boiler Stop Levels .................................................................................................... 4-3
Entering Sys t em Start Temperature ................................................................................................................... 4-3
Entering Load Start Percent (Req uire d Only for Modulex Installations) .......................................................... 4-4
4.3 REMOTE SETPOINT MODE ........................................................................................................................ 4-4
Selecting Remote Setpoint Mode ...................................................................................................................... 4-5
Entering Header High Limit and Low Limit Temperatures............................................................................... 4-5
Selecting Remote Signal Type ........................................................................................................................... 4-5
Selecting Boiler Operating Mo de ...................................................................................................................... 4-6
Entering Boiler Start and Boile r Stop Levels .................................................................................................... 4-6
Entering Load Start Percent (Req uire d Only for Modulex Installations) .......................................................... 4-7
4.4 CONSTANT SETPOINT MODE ................................................................................................................... 4-7
Selecting Constant Setpoint Mode ..................................................................................................................... 4-7
Selecting Internal Setpoint Temperature ........................................................................................................... 4-8
Selecting Boiler Operating Mo de ...................................................................................................................... 4-8
Entering Boiler Start and Boiler Stop Levels .................................................................................................... 4-8
Entering Load Start Percent (Req uire d Only for Modulex Installations) .......................................................... 4-9
4.5 “TEMP AND LOAD” OPTION ...................................................................................................................... 4-9
4.6 “START ENABLED” OPTION ...................................................................................................................... 4-9
4.7 SYSTEM INITIALIZATION AND POLLING ............................................................................................ 4-10
4.8 TESTING THE SYSTEM ............................................................................................................................. 4-10
CHAPTER 5 - TROUBLESHOOTING ............................................................................................................. 5-1
5.1 FAULT MESSAGES & COMMON PROBLEMS ......................................................................................... 5-1
APPENDIX A - BMS MENUS A-1
APPENDIX B - STATUS AND FAU LT MESSAGES B-1
APPENDIX C - METHODS FOR DETERMINING RESET SCHEDULE C-1
APPENDIX D - NTC TEMPERATURE RESISTANCE CHART D-1
APPENDIX E - BMS II WIRING DIAGRAM E-1
APPENDIX F - BMS II PARTS AND ACCESSORIES F-1
APPENDIX G - PROGRAMMING THE BMS II USING RS232 COMMUNIC ATI ON G-1
APPENDIX H - BMS II MODBUS ADDRESS ASSIGNMENTS H-1
APPENDIX I - BOILER START AND BOILER STOP LEVELS I-1
v
GENERAL INFORMATION
CHAPTER 1 - GENERAL INFORMATION
1.1 SAFETY PRECAUTIONS & WARNINGS
The Warnings and Cautions appearing throughout this manual should be reviewed and thoroughly
understood prior to attempting to install, operate, troubleshoot or repair the BMS II.
1.2 INTRODUCTION
This manual provides installation, operation and troubleshooting instructions for the AERCO Boiler
Management System, Model 5R5-384. Since this Model is the second generation of AERCO’s Boiler
Management System (BMS) line, this Model is referred to as the BMS II throughout this document.
1.3 BMS II GENERAL DESCRIPTION
The BMS II (Figure 1-1) is a rugged , flexible contro ller designed to stag e and coordinate the o peration of
up to 32 AERCO Benchmark Series, Modulex Series or KC1000 Boilers while maximizing operational
efficiency. Under norm al lo ad condit ions, t he BM S II can pr ecise ly regu late the header tem perat ure of the
boiler plant within ±2°F.
Boiler plant control is accomplished via a RS485 network utili zing Mo dbus pr otoc ol. For facilities that have
taken a building-wide appr oach to energy eff iciency, the BMS II can be easi ly integrated with an Ener gy
Management System (EMS) or Building Automation System (BAS) utilizing Modbus protocol. Physical
connection to the rem ote EMS or BAS is accom plished vi a an RS232 interface. EMS/BA S integratio n will
also permit utilizat ion of the pass-thru function incorporated in the B MS II. The pa ss-thru f unction permits
the remote system to monitor up to 35 operating parameters from each boiler in the plant.
The BMS II is housed in a NEMA 13 e nclosur e. A hin ged cle ar-plas tic c over ove r the unit ’s panel cont rols
protects against inci den tal cont act of control settings a nd pro vi des a degree of protection a ga ins t a irbor n e
debris and the spraying or splashing of water. The physical dimensions, weight and electrical power
requirements for the BMS II are as follows:
Dimensions 9.50” W x 7.25” H x 4.00” D
Weight 3 lbs.
Power Requirements 85-to-265 VAC, Single-Phase, 50-60 Hz @ 1A
Each BMS II shipment includes a Header Sensor Kit, Part No. GM-122790 which is required for all modes
of operation. Other available options which can be ordered with your shipment include:
Outdoor Air Sensor Kit,
Part No. GM-122781
Required for Outdoor Reset Mode Operation
Return Sensor Kit,
Part No. 122790
(Same as Header Sensor Kit)
RS485-to-RS232 Converter, Part
No 124943
Used for external monitoring of boiler water return
temperature
For use with EMS or BAS equipment that do not include
a RS232 Port
1-1
GENERAL INFORMATION
WIRING
COMPARTMENT
COVER
CONTROL
PANEL
CLEAR
PLASTIC
COVER
1.4 BMS II FEATURES
The following paragraphs briefly describe some of the unique features incorporated in the BMS II.
Simplified Installation and Set-Up
The BMS II system operates on single-phase input power ranging from 85 to 265 VAC, 50-60 Hz.
Connections to the boi ler plant are accom plished utilizing a 2-wire RS485 networ k connected in a d aisychain configuration. W hen an EMS or BAS is used with the B MS II, connec tions ar e made via the RS2 32
port terminals. In the event that the EMS or BAS is not equipped with a RS232 port, the BMS II can be
ordered with a RS485 to RS23 2 Converter which can be easily insta lled withi n the wiring c ompartm ent of
the BMS II. With the exception of AC power, interlock and setback inputs and relay outputs, BMS II
connections are accomplished using twisted-shielded pair cable.
User-Friendly Control System Interface
The unit incorporates a menu-driven architecture which is comprised of 9 primary menus. The user
interface to these m enus is ac c om plished v ia t he BM S I I contr ol pa nel and a V acuum Fluorescent Displ a y
(VFD). The displa y is c a pa ble of dis p laying two lines w ith 16 char ac ters per line. V ir tua ll y al l of t he c o ntrol
panel keys are identical to the C-More Contr ol System c urrently used on A ERCO Benchm ark Series and
KC1000 Boilers. This commonality will help simplify the time required for system setup of the BMS II.
Figure 1-1. Boiler Management System II (BMS)
1-2
GENERAL INFORMATION
Retention of Menu Option Settings
By using non-volatile memory, the BMS II retains program and menu settings during shut-down or when
input AC power is interrupted. Settings can be retained for more than 2 years.
Application Flexibility
Four different configuration options can be selected to match the needs of any closed-loop system. These
configurations are: Outdoor Reset, Constant Setpoint, Remote Setpoint via a 4-20 Ma input and Remote
Setpoint via Modbus.
Sequential or Parallel Operation
Boilers can be programmed for either sequential or parallel operation using the BMS II keypad controls. When set
for sequential operation, the boilers are brought on-line one at a time as needed. When set for parallel operation, the
boilers are all brought on-line together at the same firing rate.
Accuracy
Using PID (Proportional Integral Derivative) and Ramp-Up/Ramp-Down Modulation Control Algorithms,
the BMS II provides dynamic responses to all changes in boiler plant operation. Header temperatures, as
well as percentages of boiler input are precisely controlled with virtually no over-shoot or short-c ycling of
boiler units. A header temperature accuracy of ±2°F is virtually assured during continuous plant operation.
Bumpless Transfer
When operated sequentially, The BMS II stages boilers on and off at selectable firing rate percentages.
The result is a seamless transition with undetectable room temperature changes. In addition, when in
sequential mode, the BMS II sequences boilers using a first-on, first-off basis, thereby equalizing the
accumulated run time of all boilers in the plant.
The BMS II also continuously monitors the number of Boilers that are available for operation. In the event
of a boiler malfunction, or required servicing, the BMS II automatically compensates for a lack of
response from any unit and brings on the next available boiler to satisfy the demand. This feature
operates in both sequential and parallel modes.
Fault Alarm Surveillance
If an EMS or BAS is not used with the BMS II to monitor faults, a Fault Alarm Relay can be activated
thereby notifying facility managers of faults associated with the BMS II.
BMS II Programming Via RS232 Port.
If desired, the BMS II can be programmed by connecting a Laptop Computer or other terminal emulation
device to the RS232 Port terminals on the BMS II. Detailed set-up instructions and available command
listings are provided in Ap p end ix G. Most settings are also programmable using Modbus.
1-3
INSTALLATION
CHAPTER 2 - INSTALLATION
2.1 INTRODUCTION
This Chapter provides the descriptions and procedures neces sary to mount the BMS II and connect all
boiler plant units and applic able sensors. Guideli nes are also provided for connec tion of an EMS or BAS
being used with the s ystem. Ref er to the wiring diagram provided in Appen dix E when mak ing all wiring
connections to the BMS II.
2.2 SITE SELECTION AND MOUNTING
Ensure that the site selected for installation of the BMS II provides the following:
• Access to single-phase AC power from 110 to 240 VAC, 60 Hz nominal
• Sufficient clearances to permit maintenance and setup/operational tasks on the BMS II.
Mounting the BMS
AERCO recommends that the BMS II be wall-mounted using a sheet of plywood or other suitable
material. For easy viewing, the BMS II controls and display should be at eye level. Mounting is
accomplished using three screws (not provided). The s pacing for the three screws are indicate d on the
rear of the BMS II in millim eters. Figure 2-1 shows th e rear of the panel enc losure and also in dicates the
required spacing for the three mounting scr ews in inch es . Proceed as follows to mount the unit:
1. First install a screw o n the mounting sur face at the to p center locatio n shown in Figure 2-1. Lea ve a
space of approximately 1/8 inch between the mounting surface and the head of the screw.
2. Remove the wiring compartment cover f rom the front of the BMS II (see Figure 1-1) to provid e acc es s
to the slots for the two lower mounting screw locations.
3. Hang the BMS II on the installed top screw. Position the unit so it is level.
4. Mark the locations for the two lower screws.
5. Remove the BMS II and drill two pilot holes for the lower screws.
6. Replace the BMS II on the installed top-center screw.
7. Secure the BMS II to the wall by installing the two lower screws. DO NOT over-tighten the screws.
2-1
INSTALLATION
198 mm (7.8")
145 mm (5.7")
15 mm
(0.6")
REAR VIEW
Figure 2-1. BMS II Mounting Provisions
2.3 GENERAL WIRING REQUIREMENTS
All wiring connections to t he BMS II are made at th e terminals located behind the wiring compartment
cover as shown in Fi gure 2-2. Run all wiring t hrough the knock-outs provided on the bottom sur face of
the unit. Shielded, twisted-pair cable should be used for sensor and communication wiring. This wiring
should be 18 to 24 AWG. Examples of s uitable sensor and comm unication wire are: Belden 9841, 87 61,
3105A or equivalent. AC power wiring should be 1 4 to 18 AWG. The BMS II wiring diagram is provided in
Appendix E. Once mount ing is com plete and the BMS is secured in p lace, loose n the two ca ptive scr ews
on the wiring compartment cover using a Phillips screwdriver. Feed all wiring through the knock-outs
provided on the bottom of the panel.
NOTE
Refer to the wiring diagram provided in Appendix E when making all
wiring connections to the BMS II.
2-2
INSTALLATION
WARNING
THE BMS II CAN BE POWERED BY SINGLE-PHASE AC
VOLTAGES RANGING FROM 85 TO 265 VAC. THEREFORE,
EXERCISE EXTREME CARE WHEN CONNECTING POWER
WIRING TO THE UNIT. ENSURE THAT THE EXTERNAL
CIRCUIT BREAKER SUPPLYING LINE VOLTAGE TO THE BMS
II IS TURNED OFF TO AVOID SEVERE ELECTRICAL SHOCK.
2.4 POWER WIRING
Use 14 to 18 AWG wire for AC power connections and proceed as follows:
1. Feed the power wiring thr ough the right-m ost knock -out in the bottom of the panel enclosure (Figure
2-2).
2. Connect the Line (black ), Neutral (white) and Groun d (green) wire leads to the L, N an d
terminals. The term inal blocks can be detac hed fr om the BMS II headers if necess ary to sim plify field
wiring connections.
3. Following completion of power wiring, turn on the exter nal circuit breaker or switch and apply power
to the unit. The BMS II display will momentarily show:
AERCO BMSII
REV X.XX
(Where: X.XX represents the revision level of the installed BMS II software)
4. Next, since the Header Sensor is not yet installed, the display will then show:
HEADER TEMP
SENSOR ERROR
The red FAULT LED indicator will also light and a fault message will alternately be displayed as
follows:
HEADER SENSOR
ERROR
5. Press the ON-OFF k ey on the keypad. The green ON LED indicator w ill light and the BMS II d isplay
will continue to show the above message.
6. After verifying proper power connections, press the ON-OFF key. The ON LED will turn off.
(GND)
7. Turn off the external power switch and/or circuit breaker. The BMS II display will go blank.
8. DO NOT apply power to the BMS II until all of the required external connections described in
paragraphs 2.5 through 2.11 have been completed.
2-3
INSTALLATION
SENSORS
& 4-20 mA
INTERLOCKS
& SETBACK
RS485
& RS232
AC POWER
RELAYS
2-4
Figure 2-2. BMS II With Wiring Compartment Cover Removed
INSTALLATION
2.5 SENSOR INSTALLATION AND WIRING
There are two types of sensors that can be installed : a Header Sensor and an Outside Air Sensor. If
desired, an optional Return Sensor can also be installed. The Return Sensor is the same type and part
number as the Header S ensor, however it is only used for `external m onitoring purposes. The Header
Sensor is required for all
Outdoor Reset Mode.
All Sensor wiring should be run separately from power wiring to avoid inducing electrical noise on the
sensor wiring.
Header Sensor
A Header Sensor Kit, (part no. 12279 0) is provided with the BMS II. This Kit cont ains the Header Sensor
(64038), a Thermowell (122758) and some heat conductive grease which MUST be use d with the Sens or.
When installing the Sensor , use a 1/ 2 inch NPT tapped coupling or a 4 x 4 x 1/2 in ch T ee fitting. Shielded
pair, 18 AWG c able (Belden # 8760 or equiv.) is recommended for Header S ensor wiring. The Header
Sensor must be installed between 2 and 10 feet downstream of the LAST boiler in the boiler plant’s
supply water header. Install the Header Sensor as follows:
The Header Sensor is a thermistor type sensor. The Resistance vs.
Temperature Chart for this sensor is provided in Appendix D. The length
of the Header Sensor wire leads should not exceed 600 feet.
modes of operation. The Outdoor Air Sensor is required for operation in the
NOTE
1. Refer to Figure 2-3 f or the Header ‘Sens or ins ta llat ion details.
2. Install the Header Sensor and Thermowell i nto the 1/2 inch NPT tapped c oupling or a 4 x 4 x 1/2 inch
Tee fitting using heat-conductive grease provided. This will aid in its response.
3. For proper response , e ns ur e th at t he Hea der Sensor probe is inser ted at le ast 2 inc hes i nto the wat er
flow.
4. Using shielded pair c able (Belden #8760 or equiv.) connect t he Header Sensor leads to HDR SE N
terminals 4 and 5 on the BMS II. There is no polarity to observe when making these connections.
5. Terminate the cable shield at SHLD terminal 3 of the BMS II. DO NOT terminate the shield at the
Sensor end of the cable.
Return Sensor
As mentioned in paragraph 2.5, the Return Sensor is identical to the Header Sensor. Therefore, if a
Return Sensor is being ins talled, another Header Sensor K it (part no. 122790) is required. The Ret urn
Sensor should be i nstal led in the boiler water r eturn lin e within 3 feet of the first boil er in t he bo iler p lant ’s
return water line . The installation details sho wn in Figure 2-3 for the Header S ensor also apply to the
Return Sensor. If used, install the Return Sensor as follows:
1. Refer to Figure 2-3 an d ins tall the Ret ur n S ens or a nd Thermowell into the 1/2 inc h t ap ped c oupling or
or Tee fitting using heat conductive grease.
2. Using shielded pair ca ble (Belden #8760 or equiv.) connect the Retur n Sensor leads to term inals 6
and 5 on the BMS II. There is no polarity to observe when making these connections.
3. Terminate the cable shield at SHLD terminal 3 of the BMS II. DO NOT terminate the shield at the
Sensor end of the cable.
2-5
INSTALLATION
PROBE DEPTH MUST
EXTEND AT LEAST 2"
INTO PIPE
WELDED 1/2"
COUPLING OR
4"x4*x1/2"
T - FITTING
HEADER SENSOR
WITH THERMOWELL
INSTALLED
Figure 2-3. Header Sensor Installation Details
Outdoor Air Sensor
The Outdoor Air T emperature Sensor (part n o. GP-122662) is r equired when operating in the BMS II in
the Outdoor Reset Mode (paragraph 4.2). An Outdoor Air Sensor Kit (part no. GM-122781) is also
available. This kit contains the Sensor (GP-122662) and a Mounting Bracket for wall mounting. The
Outdoor Air Sensor should be mounted on the North side of the building, shielded from direct sunlight,
and awa y from air intakes or outlets f rom the building. Shielded pair 18 AWG cable (Belden # 8760 or
equiv.) is recomm ended for sensor wiring. The Outdoor Air Sensor can be m ounted up to 600 feet from
the BMS II.
1. Refer to Figure 2-4 for a typical Outdoor Air Sensor installation.
2. Attach the sensor to the mounting br acket and secure the bracket in a suitable loc ation on the North
side of the building.
3. Using shielded pair cable ( Belden #8760 or equiv.), connect t he two Sensor lea ds to terminals 1 and
2 on the BMS II. There is no polarity to observe when connecting the sensor.
NOTE
The Outdoor Air Sensor is a thermistor type sens or. The Resistance vs.
Temperature Chart for this t ype of s ensor is provi ded i n Appendix E. T he
length of the Header Sensor wire leads should not exceed 600 feet.
2-6
INSTALLATION
INSTALL SENSOR ON NORTH
FACING WALL OUT OF DIRECT
SUNLIGHT AND AWAY FROM
ALL AIR INLETS/OUTLETS
4. Terminate the cable shield at SHLD terminal 3 of the BMS II. DO NOT terminate the shie ld at the
Sensor end of the cable.
Figure 2-4. Outdoor Air Sensor Installation
2-7
INSTALLATION
MASTER
SLAVE
#1
SLAVE
#2
SLAVE
#3
SLAVE
#4
SLAVE
#5
2.6 RS485 (MODBUS) WIRING AT THE BMS II
The BMS II comm unicates with the AERCO Boilers over a RS485 network using Modbus pr otocol. All
Modbus networks are im plemented utilizing a Master/Slave scenario where onl y one device, the Master,
can initiate a communication sequence. AERCO Boilers equipped with C-More or E8/BCM (Modulex)
control systems can only function as Slaves on a Modbus network. However, the BMS II can function as a
Master controlling C-M ore or E8/BCM Boiler Slaves, or as a Slave contro lled by an Energ y Managem ent
System (EMS) developed by other manufacturers. Additional information on implementing Modbus
networks is provided in AERCO Modbus Communication Manual GF-114.
RS485 (Modbus) networks are wired in a “daisy chain” configuration similar to the example shown in
Figure 2-5. Shielded twisted-pair, 18 – 24 AWG cable (Belden #9841, #3105A, #8760 or equiv.) is
recommended for RS485 wiring connections.
Figure 2-5. Typical Daisy-Chain Modbus/RS485 Network
At the BMS II, RS485 (M odbus) wiri ng connections a re made at the wiring terminals labe led 485 B+ and
485 A-. The cable shield is terminated at the SHLD terminal (3) of the BMS II.
BMS II Bias Switches & Loop Termination Resistors
Each BMS II conta ins a built-in 120 ohm loop term ination resistor and two bias DIP switches which are
mounted on the lower portion of the motherboard (Figure 2-6). The 120 ohm termination resistor is always
active and is designed to matc h the electr ical im pedanc e at the B MS II end of the RS485 loop. T herefore,
only one additional termination resistor will be required at the boi ler end of the RS485 loop. The two bias
switches are used to activa te or deactiva te bias voltage on the RS485 networ k and should be positioned
as follows, depending on the type of AERCO boilers being used:
NOTE
Refer to paragraph 2.7 for detailed instructions and illustrations
describing how to implem ent loop termination, bias and wiring connections on the RS485 loop.
1. When wiring to Boiler C ontrol Modules (BCMs) controlling Mo dulex Boi lers, the BMS II bi as switches
must be activated b y placing them in the on (down) position. Loop term ination is accomplished by
activating the termination resistor in the last BCM on the RS485 loop.
2. When wiring to C-More co ntrol systems (Benchmark & KC1000 Boilers), the positions of the BMS II
bias switches will de pend on which one of the two available methods is used. Loop termination wil l
also depend on the method employed. See par agr aph 2.7 for details.
2-8
INSTALLATION
BIAS DIP
SWITCHES
NOTE:
THE BIAS DIP SWITCHES CAN BE ACCESSED
FROM THE WIRING COMPARTMENT WITHOUT
REMOVING THE FRONT PANEL FROM THE UNIT.
WIRING COMPARTMENT
Figure 2-6. Location of BMS II DIP Switches
2.7 RS485 (MODBUS) WIRING, BIAS & TERMINATION AT AERCO
BOILERS
The RS485 wiring connections at the AERCO Boilers will depend on the type of AERCO Boilers and
Control Systems bei ng used on the Mo dbus Network. Benchmark Series and KC1000 Boilers cur rently
utilize C-More Control S ystems. Modulex Series Boilers utilize Boiler Control Modu les (BCMs) with E8
Controllers.
RS485 Wiring, Termination& Bias for Benchmark Series and KC1000 Boilers
RS485 wiring connec tions are m ade at the RS 485 CO MM term inals of each boiler’s I/O Box (Figures 2-7
or 2-8). However, activating bias and loop termination can be performed using one of two available
methods as described be lo w:
2-9
INSTALLATION
Method 1
For Method 1, the bias switches in the BMS II are left in the deactivated (up) position. ). Bias and
termination are contr olled at the b oiler end of the RS485 loop by activatin g the bias and ter mination DIP
switches on the PMC board of the last
2-7 (Benchmark), or Figure 2-8 (KC1000) and proceed as follows:
1. Using a daisy-chain wiring configuration, connect the RS485 pos itive lead to the RS485 COMM +
terminal in the I/O Box for each boiler.
2. Connect the RS485 negative lead to the RS485 COMM - terminal in the I/O Box for each boiler.
3. DO NOT terminate the shields to the Ground (G) terminal at the boiler end of the RS485 loop.
Connect the s hields of the incom ing and outgoing lea ds togeth er. The RS485 loop shield should onl y
be terminated at terminal 3 of the BMS II.
4. At the last boiler in the daisy-chain, activate the BIAS1, BIAS2 and TERM switches on the PMC board
in the C-More Control Box. Refer to G F-114, paragraph 4.3.2 for detailed instru ctions on accessing
the PMC board.
5. DO NOT activate the bias switches on the B MS II. These switches m ust be in the up position when
using Method 1.
The advantage of us ing Method 2 is that the bias and termination of the
RS485 loop do not require any changes t o be made t o the DIP s witches
on the PMC board in the last C-More Control Box.
C-More Control Box on the daisy-chain. Refer to sheet 1 of Figure
NOTE
Method 2
For Method 2, bias is controll ed at the BMS II by setting the two bias switches (Figure 2-6) to the active
(down) position. Term ination at the boi ler end of RS48 5 loop is accomplished b y installin g a 120 ohm , 1/2
Watt termination resis t or in the I/O Box of the last
(Benchmark), or Figure 2-8 (KC1000) and proceed as follows:
1. Using a daisy-chain wiring configuration, connect the RS485 pos itive lead to the RS485 COMM +
terminal in the I/O Box for each boiler.
2. Connect the RS485 negative lead to the RS485 COMM - terminal in the I/O Box for each boiler.
3. DO NOT terminate the shields to the Ground (G) terminal at the boiler end of the RS485 loop.
Connect the shields of the incom ing and outgoing lea ds togeth er. The RS485 loop shield s hould onl y
be terminated at terminal 3 of the BMS II.
4. At the last boi ler in th e daisy-chain, install a 1 20 ohm , 1/2 W att term ination res isto r ac ross the RS485
COMM + and - terminals in the boiler’s I/O Box.
5. When using Method 2, activate the two bias switches in the BMS II (Figure 2-6) by placing them in the
down position.
boiler on the daisy-chain. Refer to s he et 2 of Figure 2-7
2-10
INSTALLATION
METHOD 1 – BIAS & TERMINATION ACTIVATED AT C-MORE PMC BOARD
Figure 2-7. RS485 (Modbus) Wiring For Benchmark Series Boilers (Sheet 1 of 2)
2-11
INSTALLATION
METHOD 2 – TERMINATION ACTIVAT E D AT I/O BOX
Figure 2-7. RS485 (Modbus) Wiring For Benchmark Series Boilers (Sheet 2 of 2)
2-12
mA OUT
RS-485
COMM.
+
-
+
-
ANALOG IN
SENSOR COMMON
OUTDOOR SENSOR IN
REMOTE INTL'K IN
B.M.S. (PWM) IN
SHIELD
+
-
+
-
AUX SENSOR IN
NOT USED
EXHAUST SWITCH IN
DELAYED INTL'K IN
FAULT RELAY
120 VAC, 5A, RES
AUX RELAY
120 VAC, 5A, RES
G
NOT USED
NOT USED
NC
COM
NO
NC
COM
NO
NOT USED
NOTE
DO NOT TERMINATE THE SHIELDS OF THE
RS485 COMM LEADS TO THE GROUND (G) TERMINAL.
THE SHIELDS MUST BE TERMINATED AT THE
SOURCE ENDS ONLY. CONNECT THE SHIELDS
OF THE INCOMING AND OUTGOING RS485 LEADS
TOGETHER.
C32
Q1
C41
C29
C20
C31
C35
C47
C44
R29
R30
HB
C53
R74
C4
C3
U1
CBS3
R69
C50
R67
R68
Y1
C52
C57
J2
CR1
C1
C5
U17
R76
C51
R71
R73
R72
C2
JP2
R70
U21
C56
C6
C64
R75
J4
U13
U20
C59
C49
C48
C61
CBS4
U14
R78
R79
DS5
DS4
RS232
TX
RX
C60
C62
C46
U19
U15
U18
C58
C55
C54
DS3
R77
Y2
U16
C63
B1
R16
U11
R66
U10
R15
C45
R14
C19
C16
R32
R17
C18
R18
C34
U4
R33
C27
R31
C26
U6
R47
C39
R55
U2
R1
C7
U8
R53
C36
R81
R45
R44
C37
R48
S2
R46
C38
R49
J1
BIAS1
TERM
BIAS2
R50
C40
CBS1
RS485
C11
J3
R51
R9
BH1
U3
R10
C12
C13
DS1
RS485
TX
RX
R52
U7
DS2
R54
R5
C10
R7
R8
R6
S1
R11
R65
C9
R34
R12
R13
C14
C15
R36
C28
C25
R35
C23
R37
R38
C30
U5
C43
C65
R2
R3
R58
C8
R62
R4
R80
OFF = VOLT
CURR/VOLT
ON = CURR
Q2
R57
C66
R64
R56
CBS2
R25
U12
R20
U9
R19
C17
R27
R23
R21
R22
C21
R28
R26
C24
R60
R41
R40
R24
R39
C22
R42
R43
C33
R61
R63
C42
R59
CR2
PMC BOARD
ACTIVATE BIAS1, BIAS2 & TERM
DIP SWITCHES ON PMC BOARD
OF LAST
C-MORE CONTROL BOX
DO NOT USE THESE
TERMINALS
KC1000
REMOVE SHEET METAL
COVER TO ACCESS I/O BOX
RS485 COMM CONNECTIONS
(See NOTE)
I/O BOARD
INSTALLATION
METHOD 1 – BI AS & T E RMI NATI ON AC T IVATED AT C -M ORE PMC BOARD
Figure 2-8. RS485 (Modbus) Wiring For KC1000 Boilers (Sheet 1 of 2)
2-13
INSTALLATION
mA OUT
RS-485
COMM.
+
-
+
-
ANALOG IN
SENSOR COMMON
OUTDOOR SENSOR IN
REMOTE INTL'K IN
B.M.S. (PWM) IN
SHIELD
+
-
+
-
AUX SENSOR IN
NOT USED
EXHAUST SWITCH IN
DELAYED INTL'K IN
FAULT RELAY
120 VAC, 5A, RES
AUX RELAY
120 VAC, 5A, RES
G
NOT USED
NOT USED
NC
COM
NO
NC
COM
NO
NOT USED
NOTE
DO NOT TERMINATE THE SHIELDS OF THE
RS485 COMM LEADS TO THE GROUND (G) TERMINAL.
THE SHIELDS MUST BE TERMINATED AT THE
SOURCE ENDS ONLY. CONNECT THE SHIELDS
OF THE INCOMING AND OUTGOING RS485 LEADS
TOGETHER.
DO NOT USE THESE
TERMINALS
CONNECT 120 OHM, 1/2 WATT
RESISTOR BETWEEN + AND –
RS485 COMM TERMINALS ON
LAST
C-MORE CONTROL BOX
KC1000
REMOVE SHEET METAL
COVER TO ACCESS I/O BOX
I/O BOARD
METHOD 2 – TERMINATION ACTIVATED AT I/O BOX
Figure 2-8. RS485 (Modbus) Wiring For KC1000 Boilers (Sheet 2 of 2)
2-14
INSTALLATION
Y2
Y3
Y4
Y1
SW1
A1
I
0
BCM FRONT VIEW
7 6 5 4 3 2 1
Y2
JP2
JP1
T
C
V
JUMPER
SHOWN IN
“TERMINATED”
(UP) POSITION
MODBUS B (+)
MODBUS A (-)
RS485 Wiring for Modulex Series Boilers
RS485 wiring connec ti ons ar e made at the MODBUS t erminals of each Boiler ’s BCM Module as shown in
Figure 2-9. Connect the wiring as follows:
1. Connect the positive lead to terminal 1 (MO DBU S B + ) of connec tor Y2.
2. Connect the negative lead to terminal 2 (MODBUS A -) of connector Y2.
3. DO NOT terminate the shields at the Boiler end of the RS485 loop. Connect the shields of the
incoming and outgoing leads together. T he RS485 loop shield should onl y be terminated at th e BMS
II.
4. The last BCM in the daisy-chain must have the termination jumper engaged as shown in Figure 2-9.
5. The two BMS II bias switches (Figure 2-6) must be activated by placing them in the down position.
Figure 2-9. RS485 (Modbus) Wiring For Modulex Series Boilers
2.8 SAMPLE RS485 (MODBUS) NE TWORK DIAGRAMS
Figure 2-10 shows a sam ple RS485 ( Modbus) Net work diagram with the BMS I I connecte d to KC1000 or
Benchmark Series Boilers equipped with C-More Control S ystems. Figure 2-11 sho ws a similar sample
diagram with the BMS II connected to Modulex Series Boilers equipped with BCMs and E8 Controllers.
2-15
INSTALLATION
BMS II
RS232 PORT
485 B (+)
485 A (-)
SHLD
(TERM. 3)
-
+
RS485
COMM
P/O I/O BOX
C-MORE
SLAVE
NETWORK BOILER 1
-
+
RS485
COMM
P/O I/O BOX
C-MORE
SLAVE
NETWORK BOILER 2
TO OTHER
NETWORK
BOILERS
(3 – 32)
RS485 PORT
NOTE
THE LAST C-MORE SLAVE ON THE RS485 LOOP
MUST HAVE ITS TERMINATION RESISTOR (TERM)
AND BIAS (BIAS1, BIAS2) DIP SWITCHES TURNED
ON. REFER TO GF-114 MODBUS COMMUNICATION
MANUAL FOR DETAILS.
THE BIAS SWITCHES IN THE BMS II SHOULD BOTH
BE “OFF”
SET BOTH
SWITCHES
TO “OFF”
BIAS
SWITCHES
BMS II
RS232 PORT
485 B (+)
485 A (-)
SHLD
(TERM. 3)
TO OTHER
NETWORK
BOILERS
(3 – 9)
RS485 PORT
NOTE
THE LAST BCM SLAVE ON THE RS485 LOOP MUST
HAVE ITS TERMINATION RESISTOR (T) ACTIVATED.
REFER TO GF-115-C FOR MORE INFORMATION.
THE BIAS SWITCHES IN THE BMS II SHOULD BOTH
BE TURNED “ON”.
SET BOTH
SWITCHES
TO “ON”
BIAS
SWITCHES
B (+)
P/O BCM (Y2)
NETWORK BOILER 1
1
2
A (-)
MODBUS
B (+)
P/O BCM (Y2)
NETWORK BOILER 2
1
2
A (-)
MODBUS
Figure 2-10. Sample RS485 (Modbus) Network For Benchmark or KC1000 Boilers
Figure 2-11. Sample RS485 (Modbus) Network For Modulex Series Boilers
2-16
INSTALLATION
RS232
(50 FT. MAX.)
EMS
T+/R+
SHLD
RS485 PORT
T-/R-
SEE NOTE 1
TO BOILERS
CONTROLLED
VIA RS485
NETWORK
(4000 FT. MAX.)
485
PORT
RXD
TXD
+(B)
-(A)
SHLD
BMS II
232
PORT
ISO
GND
+
-
TXD
RXD
GND
RS485-TO-RS232
CONVERTER
RS485
(4000 FT. MAX.)
ISO
12V
SEE
NOTE 2
T+
R-
R+
T-
SHIELD
4-WIRE RS485 PORT
DETAIL “A”
NOTES:
1. IF THE EMS CONTAINS A 4-WIRE RS485 PORT,
SEE DETAIL “A”.
2. THE BMS II PROVIDES A 12V OUTPUT IF
NEEDED TO POWER THE RS485-TO-RS232
CONVERTER.
RXD
TXD
+(B)
-(A)
SHLD
TO BOILERS
CONTROLLED
VIA RS485
NETWORK
(4000 FT. MAX.)
BMS II
485
PORT
RS232 (50 FT. MAX.)
EMS
TXD
GND
RS232 PORT
RXD
232
PORT
ISO
GND
EMS WITH RS232 PORT
EMS WITH ONLY RS485 PORT
2.9 RS232 WIRING AT THE BMS II
The BMS II comm unicates with an external Energy Mana gement System (EMS) or Building Automation
System (BAS) ut ilizing the wiring terminals labe led RXD (Receive D ata), TXD (T ransmit Data) and 232
ISO GND (Is olated Ground). If the EMS does not contain an RS232 port, a RS485-to-RS232 Converter
(AERCO Part No. 124943) is r equired to communicate with t he BMS II. If a Converter is required, it can
be installed inside the wiring compartment of the BMS II, or installed exter nally. The BMS II provides an
isolated 12 VDC output terminal (ISO 12V) which can be used to power AERCO’s RS485-to-RS232
Converter if needed. Refer to Figure 2-12 for sample network layouts.
Figure 2-12. Sample Network Connections To EMS
2-17
INSTALLATION
2.10 INTERLOCK WIRING
The BMS II is equipped with two interlocks designated Interlock 1 (INT 1) and Interlock 2 (INT 2). Since
both interlocks m us t be c lo sed f or the BM S t o o per ate the bo iler pl ant, the associated wiring terminals are
jumpered, prior to shipm ent. If desired, proving device switches can be c onnected to either
place of the jumper. If used, interlock wiring connections are made as described in the following
paragraphs.
CAUTION
DO NOT remove the factory-installed jumpers for INT1 or INT2
unless the respective Interlock is being connected to an external
proving device. The boiler plant WILL NOT operate if one or both
Interlocks remain open.
NOTE
If necessary, Interlock 1, Interlock 2 or both can be programmed
to operate the boilers only when the outdoor air temperature f alls
below the system start temperature. The selection is made with
“SYS START INTLK” in the Relay Menu. The default is set to
Interlock 1. See paragraph 3.11 for detail s.
interl ock in
Interlock 1 (INT 1) Wiring
Interlock 1 is often us ed with auxiliary equipm ent, such as air dam pers or flow switches. It can also be
used as a general purpose interlockIf used, connect the end proving switch to INT 1 terminals 9 and 10 as
shown in the wiring diagram in Appendix E.
Interlock 2 (INT 2) Wiring
Similar to Interlock 1, 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 prov ing switch to INT 2 terminals 11 and 12 as shown in the wiring d iagram in Appendix
E.
2.11 SET BACK WIRING
The SET BACK terminals, shown in the wiring di agram in Appe ndix E, are used only when im plem enting
a manually-controlled header temperature offset. If used, connect a dry contact switch across SET
BACK terminals 13 and 14. See the sub-section entitled Ma nual Offset included in par agraph 3.8 (Field
Adjust Menu),
2.12 RELAY WIRING
The BMS contains a System Start (SYS START) Relay, a Fault Alarm (FLT ALARM) Relay and an
Auxiliary (AUX) R elay which can be conn ected to external monitoring or c o ntrol d ev ic es. The contacts for
each of these relays are rat ed at 120 V AC, 5A an d are fus ed internall y at 5A with replace able f uses . The
contact terminals for these relays are shown in the wiring diagram in Appendix E.
2-18
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