LAARS NeoTherm LC NTV1700 - Install and Operating Manual - Manual (Page 67)

NeoTherm LC Boilers and Water Heaters Page 63
Job G – Disconnect Unused Touch Screens
Once a Lead/Lag system is set up and operating, the
monitoring functions will all be handled from one
Touch Screen – the one connected to the controller
operating as the Lead/Lag Master. If the extra
displays remain connected to the Lead/Lag system,
this will slow down the communications through
the system. (Each display would be considered a
leader on the Lead/Lag system.) To eliminate this
slowdown, disconnect the power from all of the
displays on the network except the display that is
connected to the controller operating as the Lead/
Lag Master.
Here is the procedure for disconnecting power to one
of the displays:
1. Turn off the power to the boiler which
includes the display you want to disconnect.
2. Open the front door to get access to the
electronics panel.
3. Locate terminal block 10 (TB10). See Fig. 78.
Remove the jumper connecting pins 1 and 2
on TB10.
Fig. 78 – Disconnecting an Unused Touch Screen
4. Close the front door and turn on power to the
boiler.
Job H - Connect the Modbus Wiring
(This is an individual function – do this on each of the controls.)
In an installation with multiple boilers, the
controllers are arranged in a “daisy chain.” The
wiring from the Secondary controller on one boiler
(TB9 - pins 7 through 12) to the Primary controller
on the next boiler (TB9 - pins 1 through 6). See
Fig. 79. Use 22 AWG or thicker shielded twisted
pair wire with drain. Two twisted pairs or three
conductors are needed.
Fig. 79 - Modbus Connections
Note – The Modbus wiring should be done last. The
controllers must be set up and addressed correctly
before the wiring is complete. If the wiring is attached
before the Modbus addresses for the controllers
are set up, there might be multiple controls with the
same address, and the system will not work.
1. Turn off the power to all of the boilers to
which you will be making connections. On
each boiler, open the front door to gain access
to the electronics panel. Locate terminal block
9 (TB9) on each panel.
2. Figure 79 shows how to make the connections.
The following table lists the connections from
Boiler 1 to Boiler 2.