INTRODUCTION
HeatNet Control V3 3.x
Page 5
Introduction
The KN-Series V3 HeatNet Control
The KN-Series V3 boiler control is the third generation of
the HeatNet control platform. Control hardware has been
added to make use of many new heating applications. These
new features are outlined in the Features & Specifications
section.
The KN-Series boiler control is designed to provide the KN-
Series of boilers with an integrated boiler management
system on every boiler. Designed for the Air-Fuel coupled
KN-Series boilers, the KN-Series HeatNet control provides
for optimized heating efficiency without the need for a “wall
mount control”. Since the KN-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 (4-20mA control loops and 0-10vdc
control voltages), a higher level of control precision,
repeatability, and feedback is gained with digital
communications control.
With the KN-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 KN-Series boilers.
The KN-Series boiler with the KN-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, WATER 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 boiler control. It shuts down the ignition
control and the boiler run enable. It protects
the boiler if the setpoint is set too high, there
is a system flow problem, or other system
malfunction. The control will continue to
function and report the fault, while in a lock-
out condition.
Each KN-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 10K Type II
temperature sensor is connected to the J10, 7 & 8.
“SYSTEM HEADER” input. A second way a boiler
becomes a MASTER is to land a 10K Type II temperature
sensor to the J10, 9 & 10 “DHW TANK” sensor input. In
the DHW menu “USE SENSOR” set to “YES” and in
“DISTRIBUTED CONTROL” set for “DHW Only” then
power cycle. The boiler is now a DHW Only, MASTER
boiler.
The MASTER senses and controls the common system
header/loop/Tank 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 controls a single boiler
(MASTER), or multiple ( MEMBER) boilers.
On a stand-alone boiler short cycling is reduced when
controlling to the “SYSTEM HEADER” as opposed to the
boiler “SUPPLY, WATER OUT” temperature.