Lead Lag Master Configuration; Connections To A Building Automation System - Bradford White Brute BNTH Installation And Operation Instructions Manual

Page 48
8.7.18 Lead Lag Master Configuration
Then set up the Master controller by going to the Lead
Lag Master boiler and opening up the Lead Lag
Master Configuration in that boilers Configuration
Menu. Select Master Enable
Select OK and then Back out to the Main Menu.
Wiring Connections for Lead/Lag -
Now you can make the Modbus wiring connections
between the units. The controller in each boiler
includes two wiring terminals for the Modbus system,
labeled "MB1" and "MB2." MB1 has the wiring
connections to the User Interface display on each
unit, and MB2 is used to communicate with the other
boilers in the Lead/Lag system.
To reach the controller, open the cabinet of the boiler
by turning the door lock and then opening the doors.
The wiring from the controller on the first boiler runs
to the controller on the next boiler. Use
22 AWG or thicker shielded twisted-pair
wire with drain. Two twisted pairs or three
conductors are needed. Wire A on MB2 of
Boiler 1 must be connected to A on MB2
of Boiler 2, wire B on Boiler 1 goes to B on
Boiler 2, and wire C on Boiler 1 goes to C
on Boiler 2. Repeat this wiring for any other
boilers in the system. Connect all of the
drain wires and ground the drain wire on one
end of the assembly only.
Menu 24. Enabling COM2 Menu
8.8 Connections to a
Building Automation System
Brute boilers can be controlled and monitored
through the included Modbus ports. The Modbus
wiring must be completed according to the diagrams
shown below. If alternate communication protocols
are desired, Bradford White offers "gateways" to
allow BACnet, LON, and other communications
protocols. For additional information on setting up
Modbus and other communication protocols, contact
the factory.
Operator
interface
(HMI)
Figure 39. BAS connnections to a Single Boiler
Second or
slave
boiler
Controller
Operator
interface
(HMI)
MB1 MB2
Figure 40. BAS connnections to a Lead Lag System
B
RADFORD
Customer
Boiler
communication
(RS-485)
Controller
MB1 MB2
communication
Lead or
master
boiler
Controller
MB1 MB2
TB3 - 24VAC
TB4 - NEU
W
HITE
Customer
(RS-485)
Com2
Master
System
display
Com1