RBI Encore Series Use and maintenance manual

09/2022 Copyright 2022Mestek, Inc.
This manual is intended only for use by a qualified heating installer/technician. Read and follow this manual, all
supplements and related instructional information provided with the boiler. Install, start and service the boiler only
in the sequence and methods given in these instructions. Failure to do so can result in severe personal injury,
death or substantial property damage.
Do not use the boiler during construction. Construction dust and particulate, particularly drywall dust, will cause
contamination of the burner, resulting in possible severe personal injury, death or substantial property damage.
The boiler can only be operated with a dust-free air supply. Follow the instruction manual procedures to duct air to
the boiler air intake. If the boiler has been contaminated by operation with contaminated air, follow the instruction
manual guidelines to clean, repair or replace the boiler if necessary.
Affix these instructions near to the boiler. Instruct the building owner to retain the instructions for future use by a
qualified service technician, and to follow all guidelines in the User’s Information Manual.
ECRV3-0922
82-0971-001
H
Encore Series
Gas-fired Direct Vent
Stainless Steel Boilers
Models:
RB350, RB400, RB500,
RB600, RB725, RB850
Control Manual
Control adjustment and operation instructions
for RBI firmware version 4.15
This instruction manual applies only to RBI
firmware version 4.15 on version 3.x control
boards.
Also read and follow:
Encore Series Gas Boiler Installation
and Operating Instructions

Information contained in this publication regarding device applications and
the like is provided only for your convenience and may be superseded by
updates. It is your responsibility to ensure that your application meets with
your specifications.
RBI MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND
WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY
OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT
NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE,
MERCHANTABILITY OR FITNESS FOR PURPOSE.
http://www.rbiwaterheaters.com/
The RBI name and logo, Mestek name and logo, Encore Series,
HeatNet, and H-Net name and logo are registered trademarks of
Mestek, Incorporated in the U.S.A. and other countries.
BACnet is a registered trademark of ASHRAE. LonWorks is a
registered trademark of Echelon Corporation. All trademarks
mentioned herein are property of their respective companies.
© 2020, Mestek Technology Incorporated, Printed in the U.S.A., All
Rights Reserved.

TABLE OF CONTENTS HeatNet Control V3
Page 3
Table of Contents
Table of Contents.................................................................................................................................3
Introduction..........................................................................................................................................6
THE ENCORE SERIES V3 HEATNET CONTROL ....................................................................................................................................6
Features & Specifications ...................................................................................................................8
STANDARD FEATURES OVERVIEW .....................................................................................................................................................8
Specifications.....................................................................................................................................10
Components & Accessories..............................................................................................................11
PART NUMBER .............................................................................................................................................................................. 11
Setup & Operation..............................................................................................................................12
BASIC MULTI BOILER SYSTEM OPERATION ....................................................................................................................................... 12
MIXED BOILER TYPES USING PRIORITY SETS ................................................................................................................................... 13
MIXED BOILER SYSTEM OPERATION ................................................................................................................................................ 13
START/STOP PRIORITY CONDITIONS ............................................................................................................................................... 16
SELECTING MIXED BOILERS ............................................................................................................................................................ 17
MIXED SYSTEM TYPE 1: HIGH SYSTEM TURNDOWN.......................................................................................................................... 17
MIXED SYSTEM TYPE 2: CONDENSING/NON-CONDENSING ................................................................................................................. 20
Heating Control Methods...................................................................................................................24
HEATING METHOD 1 ...................................................................................................................................................................... 24
HEATING METHOD 2 ...................................................................................................................................................................... 24
HEATING METHOD 3 ...................................................................................................................................................................... 24
HEATING METHOD 4 ...................................................................................................................................................................... 24
HEATING METHOD 5 ...................................................................................................................................................................... 24
OPERATING LIMIT .......................................................................................................................................................................... 24
INPUT PRIORITIES .......................................................................................................................................................................... 25
HEATING METHOD 1 HEAT DEMAND ............................................................................................................................................ 25
HEATING METHOD 2 STAGE CONTROL T1-T2 ................................................................................................................................ 26
HEATING METHOD 3 4-20MA CONTROL ........................................................................................................................................... 26
HEATING METHOD 4 AA INPUT........................................................................................................................................................ 27
HEATING METHOD 5 MODBUS COMMUNICATIONS ........................................................................................................................... 27
Domestic Hot Water Methods............................................................................................................28
DHW METHOD 1: DHW HEATING ONLY USING A DHW MASTER AND MEMBER BOILER(S) EMPLOYING H-NET ................................... 30
DHW METHOD 2: FAILSAFE COMBINATION DHW AND SPACE HEATING WITH A MASTER BOILER AND MEMBER BOILERS UTILIZING
VALVES (MASTER TYPE: COMBINATION) ......................................................................................................................................... 34
DHW METHOD 2: FAILSAFE COMBINATION DHW AND SPACE HEATING WITH A MASTER BOILER AND MEMBER BOILERS UTILIZING
PUMPS (MASTER TYPE: COMBINATION) ......................................................................................................................................... 36
DHW METHOD 3: DHW HEATING ONLY, USING A HEADER SENSOR INPUT ......................................................................................... 41
DHW METHOD 4A: SPACE HEATING WITH DHW OVERRIDE OF SETPOINT ON MASTER, USING AN AQUASTAT ......................................... 44
DHW METHOD 4B: SPACE HEATING WITH DHW OVERRIDE OF SETPOINT ON MASTER, USING A DHW 10K TANK SENSOR ..................... 47
DHW METHOD 5A: LOCAL DHW TANK HEATING USING A 10K TANK SENSOR. .................................................................................... 50
DHW METHOD 5B: LOCAL DHW TANK HEATING USING A THERMOSTAT & HYBRID SENSOR. ................................................................ 54
DHW METHOD 6: DHW USING DIRECT CONTROL ......................................................................................................................... 56

Page 4
DHW MAXIMUM RUNTIME .............................................................................................................................................................. 56
BASE LOADING, RELAY CONTROL ................................................................................................................................................... 57
Using the 4-20mA input (OPTIONAL)................................................................................................60
SETPOINT PRIORITIES .................................................................................................................................................................... 61
Circulator Pump Options ...................................................................................................................61
Local Pump Options...........................................................................................................................63
Combustion Air Damper ....................................................................................................................64
Outdoor Reset.....................................................................................................................................64
Sensors...............................................................................................................................................65
Stack Temperature .............................................................................................................................65
Local Flow Sensor..............................................................................................................................65
Security...............................................................................................................................................66
Save/Restore Configuration Settings................................................................................................66
USB Features......................................................................................................................................67
Diagnostics.........................................................................................................................................67
Blower Protection...............................................................................................................................67
Communications ................................................................................................................................68
Failsafe Modes....................................................................................................................................68
FAILSAFE REQUIREMENTS .............................................................................................................................................................. 68
Limited Flow Boiler Control Options.................................................................................................69
HeatNet Online....................................................................................................................................71
Wiring Connections............................................................................................................................72
Home Screen Navigation ...................................................................................................................83
Home Screen ......................................................................................................................................84
Home Screen Messages.....................................................................................................................85
HEATING MODE MESSAGES ............................................................................................................................................................ 85
SETPOINT SOURCE MESSAGES ....................................................................................................................................................... 86
GENERAL MESSAGES .................................................................................................................................................................... 86
Calibration...........................................................................................................................................93
Log Entry.............................................................................................................................................94
Control Settings Menu .......................................................................................................................95
Control Settings Menu —Page 1.......................................................................................................96
Control Settings Menu —Page 2.....................................................................................................104
Control Settings Menu —Page 3.....................................................................................................112
Control Settings Menu —Page 4.....................................................................................................113

TABLE OF CONTENTS HeatNet Control V3
Page 5
MODBUS Communications .............................................................................................................116
Worksheet.........................................................................................................................................128
Type II Thermistor Resistance/Temperature Table........................................................................133

Page 6
Introduction
The Encore RB Series V3 HeatNet
Control
The Encore Series boiler control is designed to provide the
Encore Series of boilers with an integrated boiler
management system on every boiler. Designed for the Air-
Fuel coupled Encore Series boilers, the Encore Series
HeatNet control provides for optimized heating efficiency
without the need for a “wall mount control”. Since the
Encore modular control method is based on digital
communications, analog control signals are not required.
Although the use of analog control signals is still supported
(4-20mA control loops and 0-10VDC control voltages), a
higher level of control precision, repeatability, and feedback
is gained with digital communications control.
With the Encore Series, optimized heating efficiency is
accomplished by setting the Modulation Maximum (Mod-
Max) setting to exploit the inverse efficiency curve. This
value can be adjusted so that as each boiler is added, it
operates at its maximum turndown. This allows the
maximum number of boilers to operate at their lowest
inputs, until all boilers are firing. Once all boilers are firing,
full range modulation control is allowed. An outdoor reset
function is also provided to assist in the optimized heating
efficiency of the Encore Series boilers.
The Encore Series boiler with the Encore Series H-Net
control, can be operated in multiple ways:
1. As a stand-alone boiler.
2. A boiler, in a Boiler Network, using the HeatNet®
(H-Net®) protocol.
3. A member boiler to a boiler management system with
multiple input control methods.
Home Screen
The primary purpose of the control is to maintain the boiler
water temperature at the supply or the header sensor using a
target setpoint. This function is displayed in the Home
Screen. While performing this task, the control also
monitors dedicated external limits in a limit string and
provides an orderly shutdown and fault indication in the
event of a tripped limit. The monitored limits include a
HIGH LIMIT AQUASTAT, LOW WATER CUTOFF,
GAS PRESSURE, FLOW, IGNITION CONTROL fault,
GAS VALVE alarm, VARIABLE FREQUENCY DRIVE
alarm, and other optional or user selectable limits.
The HIGH LIMIT circuit is independent of
the HeatNet control, which shuts down the
ignition control and the boiler if the control
board or other component of the boiler were
to malfunction. The control will continue to
function and report the fault, but its ability to
run the boiler will end.
Each Encore Series boiler employing this control can
function as either a Master or a member. This allows one
boiler (Master) to be in control of target temperature. The
other boilers (Members) only respond to the commands
issued by the Master. If using an external control, all boilers
can be setup as members. The following will define the
roles of Master and member.
Master
A boiler becomes a Master when a temperature sensor is
connected to the J10 “SYSTEM HEADER” terminals. The
sensor is auto detected.
The Master senses and controls the common system
header/loop water temperature using a system setpoint. It
uses any boilers it finds (over the H-Net communications
cable) to accomplish this. It can also monitor the Outside
Air (OA) temperature to provide outdoor reset functionality.
Only one Master is allowed in a system.
When operating as a Master, the boiler provides a control
method using a PID algorithm to regulate water
temperature. This algorithm allows for a single boiler
(Master), or multiple (Master + Member) boilers.
Heat band
SETPOINT
UPPER HEAT
BAND LIMIT
LOWER HEAT
BAND LIMIT Boilers Staged
ON
BOILERS
STAGED
OFF
Time
WATER
TEMPERATURE
The control algorithm is based upon a Heat Band, at the
center of which is the setpoint. While below the Heat Band,
boilers are staged on and modulated up until the Heat Band

FEATURES & SPECIFICATIONS HeatNet Control V3
Page 7
is entered. Once in the Heat Band, modulation is used to
maintain setpoint. Boilers are shut down only when the top
of the Heat Band is breached. Timers are also used to
prevent short cycling.
While staging the boilers on, a modulation clamp is used to
hold the boilers at a lower fire rate until the last boiler is
fired. Once the last boiler fires the modulation clamp is
removed, and all boilers are allowed to fire above this
clamped percentage up to 100%. This “boiler efficiency”
clamp is defaulted to 70% and thus limits all boilers
individual outputs to 70% until the last boiler fires. All
running boilers modulate up and down together, always at
the same modulation rate. As a rule, this percentage should
be no lower than twice the minimum turndown to minimize
short cycling.
When additional boilers are needed to achieve setpoint in
the system, the Master boiler employs an ADAPTIVE
MODULATION algorithm to prevent over firing of the
system. The Master communicates over the H-Net to view
the exact status of each Member boiler. When a new boiler
is added, the Master boiler adjusts the system modulation
rate lower to compensate for the BTUs that will be
introduced by the newly added boiler. This adjustment
occurs when the newly added Member boiler enters its ON
CALL state (default setting). This can be changed to
IGNITION when the new boiler is called using the menu:
ADAPTIVE MOD: DROP DOWN. Once the Main Valve
(on the newly added boiler) is opened, and the DELAY
RELEASE timer equals zero, the PID algorithm is allowed
to control the system modulation. Setting the DELAY
RELEASE timer will allow some “soak” time of the newly
added boiler before releasing modulation control to the PID.
The ADAPTIVE MOD menus are disabled
on a Member boiler, but are still visible.
Member
If a “SYS/DHW HEADER” sensor is not connected to J10,
a boiler always defaults to the role of Member.
The Member boiler can operate as part of a multi-boiler
system or as a stand-alone unit.
In a multi-boiler system, the Member typically receives its
command signals from a designated Master-boiler. It is also
capable of receiving inputs from an external control system.
The boiler responds to these signals, to start/stop the burner,
and/or to modulate the firing rate. The outlet water
temperature is also monitored. If the outlet temperature
approaches the operating limit temperature setpoint
(adjustable), the boilers’ firing rate is limited, and its
modulation value is reduced to minimize short cycling. If
the operating limit is exceeded, or if an interlock trips, the
boiler is shut down. When connected with a network cable,
in a Master/Member role, the Members' status is
interrogated by the Master boiler.
In a stand-alone installation the Member typically receives
its command signals internally and operates based upon the
outlet water temperature input and the established settings in
the menu (Local Set-point) to start/stop the burner, and/or to
modulate the firing rate. If the operating limit is exceeded,
or if an interlock trips, the boiler is shut down. As in a
multi-boiler system, a stand-alone Member boiler is also
capable of receiving inputs from an external control system.
When using the H-Net network cable in a Master/Member
system, the system setpoint is sent from the Master as a
digital signal, along with the modulation value to control
firing rate. It also receives its command to start or stop over
the H-Net cable. Also, the SYSTEM CLOCK only needs to
be set on the MASTER. The Master will then set the time
on all member boilers.
If not using the H-Net protocol (cable), an external control
can send a 4-20mA signal along with a 4-20mA enable
signal to control the firing rate or setpoint. The boiler may
also be treated as a 2-stage boiler or an ON-OFF boiler
using the dedicated T-inputs.

Page 8
Features & Specifications
Hardware Version 3.x Control
Features
(Identified by circuit board color: BLACK)
1. Support for (2) Circulator pumps. Two rotation modes
are provided: Based on system runtime or system pump
runtime hours. Pump failure switchover/retry mode.
2. Warm weather shutdown, (2) pump jog and local pump
jog to keep pumps from seizing.
3. The Modbus, BACnet or LonWorks communications
port can be accessed concurrently with the USB port
(HeatNet Control Pro). The BACnet, LonWorks, or
Modbus connections do not need to be disabled to use
the USB ports.
4. The DHW pump and the Local Pump relay connections
now provide a normally closed contact. This allows for
the use of a power open/power close valve.
5. Support for 5mA 0-10VDC control signals using third
party controls.
6. Support for (2) display types: Vacuum Florescent and
Color LCD using the same 20 pin ribbon cable.
7. System Return sensor input.
8. Enhanced bootloader and firmware storage. One
firmware storage location for user updates. One
firmware program that always remains resident so that a
factory program can be restored. Primary loading is
with a flash drive.
9. Support for High Efficiency Ametek blowers.
10. 32-bit Microcontroller operating @ 64 MHz with
5-stage pipeline, and prefetch cache.
11. (3) Stage control relay outputs for TBD applications.
12. Backwards compatible with existing HeatNet versions
1.x and 2.x controls and applications.
13. Support for 135 Ohm control actuators.
14. 1k Platinum Stack sensor
15. Flow meter input or BMS GPM input/control
16. HeatNet Online network interface via the color LCD
touchscreen display.
17. Dual Adjustable PID controls. One for space heating
and one for DHW heating. Allows for simultaneous
DHW/Space heating.
18. Added High Turndown configuration resistor (100-
ohms). This configuration resistor allows the boiler to
be setup for high turndown operation. The turndown
percentage is determined by the boiler type chosen in
the menu.
Standard Features Overview
1. Five levels of external control inputs, including
modulation and staging that provide application
flexibility.
2. Digital Communications Control (analog 4-20mA and
0-10VDC control supported, but not required).
a. Boiler to Boiler: HeatNet (H-Net)
b. Building Management System (MODBUS,
Optional BACnet or LonWorks) to Boiler
3. Distributed control using the HeatNet (H-Net) protocol
for up to 16 boilers. Eliminates the need for “wall
mounted” controls.
4. Analog Control 4-20mA and 0-10VDC (5mA minimum
current) signals supported.
5. System/Boiler operating status text display
6. Interlock, Event, and System logging with a time
stamp.
7. Advanced PID algorithm optimized for the Encore
Series boilers.
8. (4) Dedicated temperature sensor inputs for: Outside
Air Temperature, Supply (Boiler Outlet) Temperature,
Return (Boiler Inlet) Temperature, and Header
(Common System Supply) Temperature.
9. Automatically detects the optional temperature sensors
on power up. (Outdoor air temperature sensor is
manually enabled in the settings menu.)
10. Menu driven calibration and setup menus with a bright
(Adj.) 4-line Vacuum Fluorescent Display.
11. (8) Dedicated 24vac interlock monitors, and 8 dedicated
120vac system monitors used for diagnostics and
providing feedback of faults and system status.
12. Multiple circulator pump control modes.
13. Combustion Air Damper control with proof time,
support for a common combustion air damper.
14. USB/RS485 network plug-in to allow firmware updates
or custom configurations.
15. Optional BACnet or LonWorks interface.
16. Alarm Relay dry contacts, and Audible Alarm.

FEATURES & SPECIFICATIONS HeatNet Control V3
Page 9
17. Runtime hours, and Cycles (based on Main Valve
Open).
18. Outdoor Air Reset with programmable setpoint and
ratio.
19. Time of Day clock to provide up to (4) night setback
temperatures.
20. Failsafe mode when a Building Management System is
controlling setpoint. If communications are lost, the
boiler/system automatically transfers to local boiler
setpoint control.
21. Rotation Methods (Lead-Lag): True Rotation (based on
boiler runtime) is default. First On First Off (FOFO),
Last On, First Off (LOFO) and MIXED are optional.
22. Programmable password protection to secure the
programmable settings.
23. Remote 4-20mA/0-10VDC setpoint control using a
mapped setpoint range to the 4-20mA/0-10VDC control
signal.
24. Freeze Protection allowing automatic starting of
boiler(s) using (2) Failsafe modes.
25. Adaptive Modulation. When additional boilers are
called, the Master adjusts all boilers fire rates to
compensate.
26. Orchestrates Mixed boiler types in a system.
27. Support for Domestic Hot Water (DHW) using a 10k
Sensor or a dry contact input from a tank thermostat.
28. Domestic Hot Water relay for use with a pump or
valve.
29. On-board power and socket for Protocessor
BACnet/LonWorks module.
30. HI/LO relay control option from connector J4
31. Resettable Fused interlock power circuit.
32. Additional terminal connector for H-Net shielded cable.
33. Backwards compatible to Version 1.x hardware.
34. Communications board integrated with the main board
from version 1.x control.
35. Base Loading of (1) boiler.
36. Delayed Blower Power staging. Used to minimize
inrush currents by powering the blower 7 seconds after
main power.
37. Domestic Hot Water time out for maximum DHW
runtime.
38. Added support for adjustable space heating and DHW
PIDs. There is now a PID rate setting that can be used
to speed up or slow down the PID response time. The
rate is a selectable Value from 2 –10, Encore boilers
default to 8.
39. Limited the rate that the 4-20mA direct modulation can
change based on the new space heating adjustable PID
rate setting.

Page 10
Specifications
Control Microprocessor based PID modulating control (NOT a safety limit)
Environment -40 °F to 140 °F, <90% RH non-condensing
Input Power 24 VAC, 500mA
Relays System Pump, Damper, Circulator, Alarm, DHW Pump (v2.x), 8A 250 VAC resistive
K8 on J4.2 &.6 for Base Loading
AC Interlocks 24 VAC –120 VAC input
Control Inputs AA, Heat Demand, 4-20mA Enable, OA override, T1-T2 (dry contact inputs)
4-20mA, 0-10VDC
Dimensions 9” wide: 6” high: 2” deep
Temperature Sensors NTC thermistor, 10K @ 77 °F, 335.67K @ -40 °F, 185 @ 150 °F, +/- 1 F
USB 1.0
RS485 MODBUS Modbus RTU
Boiler-to-Boiler HeatNet (H-Net)
Network Optional LonWorks, BACnet available bridge to MODBUS port