FEATURES & SPECIFICATIONS HeatNet Control V3
Page 6
Introduction
The FlexCore CK-Series V3 HeatNet
Control
The FlexCore CK -Series boiler control is designed to
provide the FlexCore CK -Series of boilers with an
integrated boiler management system on every boiler.
Designed for the Air-Fuel coupled FlexCore CK -Series
boilers, the FlexCore CK -Series HeatNet control provides
for optimized heating efficiency without the need for a “wall
mount control”. Since the FlexCore CK -Series modular
control method is based on digital communications, analog
control signals are not required. Although the use of analog
control signals is still supported (4-20 mA control loops and
0-10vdc control voltages), a higher level of control
precision, repeatability, and feedback is gained with digital
communications control.
With the FlexCore CK -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 FlexCore CK -Series boilers.
The FlexCore CK -Series boiler with the FlexCore CK -
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 control and shuts down the ignition
control and the boiler if the control board or
other component of the boiler was to
malfunction. The control will continue to
function and report the fault, but its ability to
control the boiler will end.
Each FlexCore CK-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
is entered. Once in the Heat Band, modulation is used to
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