LAARS NeoTherm NTV (Sizes 150–850 MBTU/h) - Install and Operating Manual - Manual (Page 50)

Page 46 LAARS Heating Systems
8C.10 Optional Field Connections
Terminal block 8 (TB8) in the control panel can be used for
connecting optional components, such as low water cutoffs,
flow switches, additional high limits and other field-supplied
devices that must be interlocked with the boiler. These are
non-powered dry contacts only. All safeties or end switches
must be wired in series by removing the supplied jumpers.
8C.11 Connections to a
Building Automation System
NeoTherm boilers can be controlled and monitored
through the included Modbus ports. The Modbus wiring
should be completed according to the diagrams shown
below. If alternate communication protocols are desired,
Laars offers “gateways” to allow BACnet, LON, and other
communications protocols. For additional information on
setting up Modbus and other communication protocols,
contact the factory.
Signals from a Building Automation System can be connected
to the MB2 Modbus connections on the controller. See Fig.
41. (MB1 is used to connect to the Operator Interface (UI).
If multiple boilers are connecting in a cascading Lead/ Lag
arrangement, the signals from the Building Automation
System must be brought in through a System Display.
See Fig. 42.
Fig. 41 - BAS Connections to a Single Boiler
Fig. 42 - BAS Connections to a Lead/ Lag System
Operator
interface
(HMI)
Boiler
Controller
MB1 MB2
Customer
communication
(RS-485)
Lead or
master
boiler
Controller Controller
Master
System
display
TB3 - 24VAC
TB4 - NEU
Operator
interface
(HMI)
Customer
communication
(RS-485)
MB1 MB1 MB2 MB2
Second or
slave
boiler
Com1
Com2