Mode Of Operation And Field - Watts AERCO Benchmark 2.0 LN Operating & Maintenance Instructions

Each of the above power configurations contain
a Power Box with a terminal block which
matches the configuration ordered. The three
different terminal block configurations are shown
in Figure 2.7. A wiring diagram showing the
required AC power connections is provided on
the front panel of each Power Box.
Each Benchmark Boiler must be connected to a
dedicated electrical circuit.
should be on the same electrical circuit as the
Benchmark Boiler. A means for disconnecting
AC power from the unit (such as a service
switch) must be installed near the unit for normal
operation and maintenance.
connections should be made in accordance with
the National Electrical Code and/or with any
applicable local codes.
For electrical power wiring diagrams, see the
Benchmark Electrical, Power Wiring Guide, GF-
2060
220 VAC, 1 PHASE
GND
NEU
L2
L1
220 VAC, 1 Phase
460 VAC, 3 PHASE
GND
L3
L2
L1
460 VAC, 3 Phase
Figure 2.7
AC Terminal Block Configurations
No other devices
All electrical
208 VAC, 3 PHASE
GND
NEU
L3
L2
L1
208 VAC, 3 Phase
INSTALLATION

2.6 MODE OF OPERATION and FIELD

CONTROL WIRING
The Benchmark Boiler is available in several
different modes of operation. While each unit is
factory configured and wired for a particular
mode, some field wiring may be required to
complete the installation. This wiring is typically
run to the Input/Output (I/O) Box located on the
front of the unit behind the removable front door
(see Fig. 2.8). A brief description of each mode
of operation, and their requirements, is de-
scribed in the following paragraphs. Additional
information concerning field wiring is provided in
paragraphs 2.7.1 through 2.7.9. For additional
information on modes of operation, refer to
Chapter 5.
LOWER RIGHT CORNER OF
FRONT PANEL
TERMINAL STRIPS
Figure 2.8
I/O Box Terminal Location
2.6.1 CONSTANT SETPOINT MODE
The Constant Setpoint Mode is used when it is
desired to have a fixed setpoint that does not
deviate. No wiring connections other than
electrical supply connections are required for
this mode. However, if desired, fault monitoring
or enable/disable interlock wiring can be utilized
(see paragraphs 2.7.9.1 and 2.7.10).
2-5