OPTIONAL FEATURES
HeatNet Control V3
Page 62
the data. If using Modbus, BACnet, or LonWorks, there are
software flag bits in registers available.
Open and shorted sensors are checked continuously, so that
in the event of a sensor failure, the system shuts down and
the alarm relay is closed.
If a pump fails (flow switch required), or the flow switch
fails, the boiler will cycle the start condition every 10
minutes in an attempt get the boiler restarted.
If the damper fails to open and never closes its proof switch,
a retry algorithm will attempt a retry. Every 10 minutes the
damper relay will cycle and try to open the damper again.
If the H-Net control closes the last interlock string connected
to the ignition control and the ignition control never closes its
Blower Relay, the H-Net control will wait 2 minutes. The H-
Net control will then retry for the duration of the local pump
post purge time and then retry the ignition sequence. During
this time “retry strt” will be displayed in the status screen.
After (5) attempts the H-Net control will lock out and display
call service.
Communications
The H-Net control has the ability to communicate using the
MODBUS protocol with a building management system.
Most registers and functions are available for MODBUS
access. Access is allowed using the RS485 MODBUS PORT
connecter on the communication board. Version 2.x Control
has these connections integrated on the main board.
An optional BACNet or LonWorks bridge module can be
used to connect the MODBUS network (Default settings) to a
BACnet or LonWorks network. See Method 5 control.
Failsafe Modes
FAILSAFE MODES have been added to help protect
systems from loss of heat conditions. When using one of
these modes
ensure that you connect any DAMPER
control, or system pump control to safely allow operation
with the assumption that the MASTER boiler or BMS system
is DOWN.
Failsafe Requirements:
1.
Since the Member boiler that will be assigned the
Failsafe duty will always turn the system pump ON, this
boiler should not be used for DHW heating. If the
Master controls the system pump, then the Failsafe
Member boiler would need to control the system pump
in parallel with the Master boiler. Wire the System Pump
contacts in parallel with the Master.
2.
If the combustion air damper is used as a common
system damper, the Failsafe boiler should be wired to
control the damper in parallel with the Master boiler.
3.
The Failsafe boiler must have the LOCAL SETPOINT
set to the same setpoint temperature as the Master
boiler’s SYSTEM SETPOINT.
Be aware that the boiler may start without a call-for-heat in
the FAILSAFE MODES. FAILSAFE MODES can be
accessed through the:
SETUP: AUX FUNCTIONS: FAILSAFE MODES
.
The following are types of Failsafe conditions.
1.
Building Management System Failure
If a BMS system is controlling the setpoint and enabling
the boiler system, a timer is provided to allow operation
of the system in the event that communications are lost
with the BMS system. The HeatNet boiler system will
run locally if communications is lost and this timer
expires due to the lack of being updated.
The system setpoint timer and system setpoint work in
tandem to externally control (i.e. a BMS - building
management system) the operating setpoint. The
setpoint (countdown) timer should be loaded with a
timeout value (in seconds) prior to writing the system
setpoint. When the timer reaches zero, the control
assumes that the BMS is no longer operating and the
local setpoint (saved on the control) is reloaded. If the
setpoint timer is not written, a default timeout value of
60 seconds is assumed. This default time is adjustable
and the setpoint timer feature may be disabled in the
COMMUNICATIONS menu. The timer is automatically
reloaded with the default value when a setpoint is
written.
The BMS mode is always on and no menu
item is available.
2.
HeatNet Communications Lost
SETUP: AUX FUNCTIONS: FAILSAFE MODES:
H-NET COMM LOST
:
This mode allows a Member boiler to run in LOCAL if
the communications link via the H-NET cable is lost.
This includes the MASTER boiler losing its Control
board, Communications board, or the power on the
MASTER is switched OFF. When this MODE is set to
ON, and if the Member boiler loses its link (heartbeat
packet over the H-NET cable) to the MASTER Boiler,
this MEMBER will fire to the LOCAL setpoint.
The heartbeat packet over the H-NET cable
needs to be lost for 10 minutes.
Summary of Contents for FUTERA XLF Series
Page 27: ...CONTROL METHODS HeatNet Control V3 Page 27 Figure 25 Base loading relay...
Page 67: ...WIRING CONNECTIONS HeatNet Control V3 Page 67 Figure 49 Jumper Dip Switch Locations...
Page 73: ...WIRING CONNECTIONS HeatNet Control V3 Page 73 Figure 57 Temperature sensors...
