LAARS Heating Systems
Page 98
Section 12
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12.1 Potential Setup and
Synchronization Problems
Because the NeoTherm 1000 uses a sophisticated
control system, it can constantly perform a series
of self-checks. For example, as a burner is lighted,
the controller checks each stage of the purge and
ignition process. If part of the process does not
happen on time, or takes too long to occur, the
controller stops the process. We have detailed these
self-checks in the section on “Operating Sequence.”
Two of these self-checks are particularly important:
• Controller synchronization
• Flap valve status
If the control system is not satisfied with the results
of both of these checks, it will not allow the system
to run. Sometimes the reason for this may not be
obvious at first – that’s why we are describing them
at the start of this section on Troubleshooting.
Operator
interface
Boiler 1
Slave 4
Boiler 2
Slave 3
Slave 2
Lead Lag
Master and
Slave 1
Slave 6
Boiler 3
Slave 5
Slave 8
Boiler 4
Slave 7
Addr
1
Addr
2
Addr
3
Addr
4
Addr
5
Addr
6
Addr
7
Addr
8
fig. 123 – lead/lag arrangement in a multiple-Boiler Installation
12.1.1 Controller Synchronization
On a multiple-boiler installation, the individual
boiler controllers are arranged in a “daisy chain”
using a Modbus connection, with the Secondary
control of one boiler connected to the Primary
control of the next boiler. Up to four boilers, with
up to eight controllers, can be connected in this way.
See Fig. 123.
As part of the setup process, each of these
controllers must be given a unique address. (For
details, see Section 9 - Installation and Setup.” The
controls must be set up and addressed correctly
before the Modbus wiring is completed. If the wiring
is attached before the Modbus control addresses are
changed, there will be multiple controls with the
same address, and
the system will not work.
When a Lead/Lag system is first powered up, the
controller acting as the Lead/Lag Master goes
through a “synchronization” process. During
synchronization, the controller establishes
communications with each of the Slave controllers
via the Modbus link. The Slave controllers
download some setup parameters and operating
history information. (On a system with several
boilers, this phase can take several minutes.) If the
Master cannot establish communications with one of
the Slaves, it triggers a Hold or Lockout.
Summary of Contents for NTV1000
Page 2: ......
Page 35: ...NeoTherm Boilers and Water Heaters Page 31 Fig 20 Ladder Diagram...
Page 36: ...LAARS Heating Systems Page 32 Fig 21 Wiring Diagram...
Page 37: ...NeoTherm Boilers and Water Heaters Page 33...
Page 51: ...NeoTherm Boilers and Water Heaters Page 47 Fig 52 Connection Terminals...
Page 130: ...LAARS Heating Systems Page 126 Fig 140 Machine Frame and Rear Panel 13 3 PARTS ILLUSTRATIONS...
Page 131: ...NeoTherm Boilers and Water Heaters Page 127 Fig 141 Front Panel and Covers...
Page 132: ...LAARS Heating Systems Page 128 Fig 142 Burners and Combustion Chambers...
Page 134: ...LAARS Heating Systems Page 130 Fig 145 Electronic Components...
Page 135: ...NeoTherm Boilers and Water Heaters Page 131 Fig 146 Condensate Trap Fig 147 Control Bezel...
Page 136: ...LAARS Heating Systems Page 132 Fig 148 Flow Switch...
Page 137: ...NeoTherm Boilers and Water Heaters Page 133 This page intentionally left blank...
