Watts AERCO EXT Instruction manual

Heating and Hot Water Solutions
AERCO International, Inc. • 100 Oritani Drive • Blauvelt, NY 10913
USA: T: [phone] • Toll Free: [phone] • AERCO.com
Technical Support • [phone] • Mon-Fri, 8 am - 5 pm EST
© 2022 AERCO
Installation, Operation & Maintenance Manual
Modulex EXT Ufly Controller & BCM
For Modulex EXT Natural Gas Modulating and
Condensing Hot Water Boilers
Applies to Modulex models:
•EXT 450 2S
•EXT 600 2S
•EXT 800 2S
•EXT 1100 2S
•EXT 1500 2S
•EXT 2300 2S
•EXT 2600 2S
•
EXT 3000 2S
Disclaimer
The information contained in this 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, not for incidental or
consequential damages occurring in connection with the furnishing,
performance, or use of these materials
OMM-0159_A •6/28/2022

Ufly Controller and BCM for Modulex EXT
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 2of 83
Table of Contents:
CHAPTER 1: INTRODUCTION..............................................................................................................5
CHAPTER 2: UFLY CONTROLLER & BCM MODULES........................................................................7
2.1 UFLY CONTROLLER.....................................................................................................................7
2.1.1 Ufly Controller Features and Functions.....................................................................................7
2.1.2 Reading the Icons on Home Page............................................................................................8
2.1.3 Display Modes.........................................................................................................................9
2.2 BOILER COMMUNICATION MODULE (BCM)..............................................................................10
CHAPTER 3: OPERATION, MENU & PARAMETERS .........................................................................11
3.1 SETUP MENU .............................................................................................................................12
3.1.1 Setting Time and Date...........................................................................................................12
3.1.2 Setting Comfort and Eco Building Reference Temperatures...................................................12
3.1.3 Setting Comfort and Eco Domestic Hot Water Setpoints.........................................................13
3.1.4 Display Settings.....................................................................................................................13
3.1.5 Language and Unit Settings...................................................................................................13
3.1.6 Password...............................................................................................................................14
3.2 HEATING MENU..........................................................................................................................14
3.3 DOMESTIC HOT WATER MENU.................................................................................................16
3.4 DEVICES MENU..........................................................................................................................17
3.5 BURNER MENU ..........................................................................................................................18
3.5.1 Service Mode/Manual Firing Rate Function............................................................................18
3.5.2 Manual Setpoint Function.......................................................................................................19
3.5.3 Reset Burner Working Hours and Ignition Count ....................................................................20
CHAPTER 4: UFLY SETUP AND PROGRAMMING.............................................................................21
4.1 INDOOR/OUTDOOR RESET MODE............................................................................................21
4.1.1 Wiring Connections................................................................................................................21
4.1.2 Indoor/Outdoor Reset Operation Configuration.......................................................................22
4.1.3 Viewing the Boiler Setpoint ....................................................................................................28
4.2 CONSTANT SET POINT MODE ..................................................................................................28
4.3 0-TO-10-VOLT REMOTE SET POINT MODE...............................................................................29
4.3.1 Wiring Connections................................................................................................................29
4.3.2 0-to-10-Volt Remote Setpoint Mode Operation Configuration .................................................30
4.4 DOMESTIC HOT WATER OPERATION USING A TANK SENSOR..............................................32
4.4.1 Sensor Wiring Connections....................................................................................................32
4.4.2 Configuring the Controller for DHW With a Tank Sensor.........................................................32
4.5 BOILER & PUMP ENABLE/DISABLE...........................................................................................36
CHAPTER 5: INPUT/OUTPUT BOX, BCM TERMINAL ASSIGNMENTS .............................................39
5.1 TERMINAL ASSIGNMENTS ........................................................................................................40
CHAPTER 6: BOILER COMMUNICATIONS MODULE (BCM).............................................................41
6.1 BCM DESCRIPTION....................................................................................................................41
6.2 BCM FAULT RELAY....................................................................................................................43
6.2.1 BCM Fault Relay Wiring.........................................................................................................43
6.2.2 Clearing Faults.......................................................................................................................43
6.3 BCM: BACKUP CONTROLLER FUNCTION.................................................................................44
6.3.1 Backup Controller Setpoint.....................................................................................................44
6.3.2 Operating the BCM as a Backup Controller............................................................................45
6.4 BCM CONTROL OF VARIABLE SPEED PRIMARY PUMP ..........................................................48
6.4.1 Pump Control Wiring..............................................................................................................48
6.4.3 Pump Control Operation.........................................................................................................48
6.5 CONTROL VIA MODBUS (THROUGH BCM)...............................................................................50
6.5.1 Operating Scenario................................................................................................................50
6.5.2 Physical Modbus RS485 Wiring.............................................................................................50
6.5.3 AERCO BMS II/ACS Master to BCM Slave Wiring Connections. ............................................51
6.5.4 EMS or BAS Master to BCM Slave Wiring Connections..........................................................51
6.6 RS485 LOOP TERMINATION RESISTORS AND BIAS................................................................51

Ufly Controller and BCM for Modulex EXT
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 3of 83
6.6.1 Master BMS II/ACS or EMS/BAS Terminating Resistor and Bias............................................52
6.6.2 BCM Controller Terminating Resistor.....................................................................................52
6.7 MODBUS NETWORK WIRING DIAGRAM ...................................................................................53
6.8 MODBUS SOFTWARE SET-UP...................................................................................................54
6.8.1 BCM Set-Up For Modbus Operation.......................................................................................54
6.8.2 AERCO ACS Modbus Control and Monitoring........................................................................56
6.8.3 Modbus Remote Setpoint Control and Monitoring...................................................................56
6.8.4 EMS or BAS Set-Up as Master to BCM Controller Slaves.......................................................56
6.9 MULTIPLE MODULEX BOILER HEATING MODE –USING ACS.................................................56
6.9.1 Sequence of Operation (Example: Four-Modulex boiler installation) .......................................57
CHAPTER 7: BCM MODBUS AND ADDRESS ASSIGNMENTS..........................................................59
7.1 BCM MODBUS COMM. & SUPPORT REQUIREMENTS .............................................................59
7.1.1 Function Codes......................................................................................................................59
7.1.2 Modbus Support Requirements..............................................................................................59
7.2 BCM CONTROLLER STANDARD HOLDING REGISTER ASSIGNMENTS..................................60
7.2.1 BCM Controller Standard Input Register Assignments............................................................60
7.2.2 BCM Controller Standard Holding Register Assignments........................................................60
CHAPTER 8: TROUBLESHOOTING ...................................................................................................71
8.1 UFLY CONTROLLER ERROR CODES........................................................................................71
8.1.1 BCM (Boiler Communications Module) Fault Codes...............................................................72
8.1.2 BMM (Burner Management Module) Fault Codes...................................................................74
APPENDIX A: BCM PARAMETERS.....................................................................................................76
APPENDIX B: BMM PARAMETERS.....................................................................................................80

Ufly Controller and BCM for Modulex EXT
CHAPTER 1: INTRODUCTION
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 5of 83
CHAPTER 1: INTRODUCTION
The information in this manual provides a guide to the operation of the Modulex Boiler using the
Ufly Controller and the Boiler Communications Module (BCM) mounted on the front of the unit.
It is imperative that the initial startup procedures be performed by factory trained personnel.
Operation by untrained personnel, prior to the initial startup, will void the equipment warranty.
In addition, CAUTIONS and WARNINGS in this manual must be observed at all times.
C A U T I O N !
It is of utmost importance to observe all CAUTIONS and WARNINGS presented in this
manual to avoid injury, death, and damage to the equipment. Failure to properly heed safety
warnings and cautions may result in the voiding of applicable warranties.

Ufly Controller and BCM for Modulex EXT
CHAPTER 1: INTRODUCTION
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 6of 83
(This page intentionally blank)

Ufly Controller and BCM for Modulex EXT
CHAPTER 2: Ufly CONTROLLER & BCM MODULES
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 7of 83
CHAPTER 2: UFLY CONTROLLER & BCM MODULES
MODULEX boilers contain advanced and reliable electronic controls, the Ufly Controller and the
BCM (Boiler Communications Module), which provide comprehensive programming and
monitoring of the MODULEX boiler and its functions. Features and functions of the Ufly
Controller and BCM are described in this chapter.
2.1 Ufly Controller
A standard component included in MODULEX units, the Ufly Controller is responsible for the
staging and modulation of individual thermal heating modules and also monitors supply and
return water temperatures and domestic hot water zones.
The Ufly Controller is mounted on the front of the MODULEX Boiler and contains all of the
controls, indicators and displays to adjust, operate and troubleshoot the MODULEX Boiler.
2.1.1 Ufly Controller Features and Functions
The Ufly features the following functions for MODULEX boilers:
•Shares the heating load among as many of the boiler's thermal heating modules as possible,
maximizing the overall operating efficiency of the boiler.
•Provides access to all testing/programming parameters of each individual heating module:
operation test, operation time, boiler freeze protection and pump's anti seize program.
•Drives lead-lag burner operation based on operating hours. The boiler module with the least
burner operating hours is the first to start and the burner with the most operating hours is the
first to stop.
•Supports DHW (Domestic Hot Water) production using a dedicated sensor to control a
dedicated pump or 3-way diverting valve for storage tank temperature control.
•Supports a manual operation service mode to control individual modules during
troubleshooting or combustion calibration procedures.
•Drives diagnostics such as relay and sensor testing.
•Supports Modbus integration with AERCO Control System (ACS) or Building Automation
Systems. AERCO also offers a Communication Gateway to support BACnet, Lonworks and
N2 system integration.

Ufly Controller and BCM for Modulex EXT
CHAPTER 2: Ufly CONTROLLER & BCM MODULES
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 8of 83
2.1.2 Reading the Icons on Home Page
Heating: Access space heating parameters including setpoint, outdoor reset
and building reference temperature.
Domestic Hot Water: Access domestic hot water parameters including
setpoint, timed programming, and legionella protection function
Solar: This menu is currently not available.
Burner: Access calibration, manual operation, and troubleshooting settings.
This menu is password protected and is only for authorized AERCO
technicians.
Setup: Access general setup parameters including time and date, display
settings, language, and units of measure.
Devices: Access BCM parameters for functions including 0-10V operation and
domestic hot water operation.

Ufly Controller and BCM for Modulex EXT
CHAPTER 2: Ufly CONTROLLER & BCM MODULES
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 9of 83
2.1.3 Display Modes
6
Display Mode
7
Display Mode
8
Display Mode
Screen Off
Home Screen
Menu Screen
NOTE: Menu icons do not indicate operating status.

Ufly Controller and BCM for Modulex EXT
CHAPTER 2: Ufly CONTROLLER & BCM MODULES
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 10 of 83
2.2 Boiler Communication Module (BCM)
The MODULEX BCM supports full interoperability to BAS (Building Automation Systems) via
Modbus protocol to enable remote communications and control. It also provides a remote alarm
contact to notify customers of faults within any of the thermal modules. Finally, in the event the
boiler's master controller stops working, the BCM also takes over operation of the boiler.
Additional control functions include the following:
•A fault relay which energizes when any fault condition occurs.
•BCM serves as a Back-up Controller if the primary Ufly Controller fails.
•BCM provides a 0-10V output for controlling a VFD primary pump.
•BCM can function as a “Client” to a “Manager” Energy Management System (EMS), Building
Automation System (BAS) or AERCO Control System (ACS) on a Modbus Network.
•BCM can start/stop the primary pump; BCM can also control a variable speed primary pump
via 0-10V analog signal.
The BCM is installed on the front of the Modulex Boiler, behind the lift-up front panel. Additional
information for the BCM can be found in Chapters 6, 7, and 8.
Figure 2-1: Boiler Communications Module (BCM)

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 11 of 83
CHAPTER 3: OPERATION, MENU & PARAMETERS
This chapter introduces the Ufly controller basic menu contents needed to set up the MODULEX
EXT boiler. For more detailed information concerning the Ufly controller menus, operating modes
and functions, refer to Section 4.
Figure 3-1: Modulex Ufly Controller Main Menu

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 12 of 83
3.1 setup Menu
The Setup Menu allows the user to setup time and date, program Building Reference
temperatures and domestic hot water setpoint, change display and language settings, and
change the password for the Devices.
3.1.1 Setting Time and Date
3.1.2 Setting Comfort and Eco Building Reference Temperatures
The Comfort and Eco Building Reference Temperatures for the Outdoor Reset Mode are
programmed in the Setup Menu. For details on Outdoor Reset Mode and Building Reference
Temperature, see Section 4.1.

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 13 of 83
3.1.3 Setting Comfort and Eco Domestic Hot Water Setpoints
The Comfort and Eco Domestic Hot Water Setpoints are programmed in the Setup Menu. For
details on Domestic Hot Water Operation, see Section 4.4.
The Ufly screen automatically turns off after 20 seconds (default) of inactivity. If the "Always on"
is toggled on like in the image below, the screen will remain on all the time.
NOTE: Do not change the value of the Modbus address. This is an internal function of the
boiler. For Modbus setup when communicating to AERCO ACS or BAS/EMS, see Section 6.8.
3.1.4 Display Settings
3.1.5 Language and Unit Settings

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 14 of 83
3.1.6 Password
For security and protection of the boiler, the default password is only available to Authorized
AERCO Service technicians.
To Change the password:
1. Enter the current password and click OK
2. Delete the current password using the backspace button.
3. Enter new password and click OK.
3.2 Heating Menu
The Heating Menu provides access to Space Heating parameters including Outdoor Reset and
Constant Setpoint Mode. For Space Heating programming details, see sections 4.1 and 4.2.
Menu
Ch13
status
Comfort
Time program
21
18
15 12 9
6
3
68°F
room

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 15 of 83
Outdoor Reset Parameter and Space Heating Setpoint are accessed via the Settings button.
Building Reference Temperatures for Outdoor Reset Mode are accessed via the Heating Menu.

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 16 of 83
3.3 Domestic Hot Water Menu
The Domestic Hot Water Menu provides access to parameters to provide domestic hot water
(DHW) using a tank sensor. For DHW programming details, see section 4.4.
The Comfort and Eco DHW Setpoints can be accessed by clicking the settings button.
The DHW Setpoint to use can be selected in the Domestic Hot Water Menu

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 17 of 83
3.4 Devices Menu
The Devices Menu allows access to BMM (Burner Management Module) parameters, BCM
parameters for functions including 0-10V operation and domestic hot water operation, and error
history. These parameters are for use by Authorized AERCO service technicians only. Password
is required to access this Menu.
Access the BCM Menu via the hcm button. See Appendix A for a list of BCM Parameters.
Access the BMM Menu vis the bmm buttons. See Appendix B for a list of BMM Parameters.

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 18 of 83
Access and clear error history.
3.5 Burner Menu
The Burner Menu allows access to calibration, manual operation, and troubleshooting settings.
This menu is password protected and is only for authorized AERCO technicians.
3.5.1 Service Mode/Manual Firing Rate Function
1. Click on the Service Mode icon.
2. Enter the password.
3. Click on the Service Mode Icon again. This will show an Activate Button.
4. Note that at this point, the screen shown is for the whole boiler.
5. Toggling the Activate button allows user to operate the boiler with a manual firing rate

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 19 of 83
6. Click on the Request +/- buttons to set the boiler manual firing rate desired.
7. If desired, user can select which burner(s) to run during manual firing rate function.
a. Select one of the available burners .
b. Note that the next screen shown is for the selected Burner.
c. Toggling the Activate button enables the selected burner to run during manual
firing rate.
d. The Current Fire Rate of activated burners will equal the manual firing rate set in
the Boiler Screen.
8. To disable the Sweeper/Manual Firing Rate Function, press the Home button .
3.5.2 Manual Setpoint Function
1. Click on the Manual Setpoint button icon. This will show an Activate Button.
2. Toggling the Activate button allows the boiler to be operated via manual setpoint.
Setpoints in Heating or DHW Mode are ignored when Manual Setpoint is activated.

Ufly Controller and BCM for Modulex EXT
CHAPTER 3: OPERATION, MENU & PARAMETERS
OMM-0159_A_A •6/28/2022 Technical Support • [phone] •Mon-Fri, 8 am - 5 pm EST Page 20 of 83
3. Click on the Request +/- buttons to set the manual setpoint desired.
4. To disable the Manual Setpoint Function, select the Home button .
3.5.3 Reset Burner Working Hours and Ignition Count
Select one of the available burners
Click the Reset button. Password will be required to proceed.