Laars NTV, Installation And Operation Instructions Manual

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Page 48
LAARS Heating Systems
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
You will be prompted to sign in. This can be done by pressing
the ‘LOCK’ symbol at the top right
type in ‘LNT’ and press OK.
Then you can select Slave Enable.
Select ‘Enable slave for built-in Lead Lag master’ .
Then select OK
Then select a Modbus address (number) for that boiler.
Then select OK
Repeat on all boilers, keeping them in a sensible sequencial
order. ’ .