Benchmark 750/1000 Boiler
Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
Page
30
of
192
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0082_0J
05/21/2014
Ph.: 800-526-0288
GF-130
2.10.8 ANALOG OUT Terminals
The ANALOG OUT terminals (+ & -) output from 0 to 20 mA and may be used to monitor
Setpoint, Outlet Temperature, Valve Position 4-20 mA, Valve Position 0-10v or be set to OFF.
Default setting in the C-More controller is Valve Position 0-10v and settings behave as follows:
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When 0-10VDC is selected, the voltage output is used by the controller to modulate the
combustion blower via the I/O Box terminals labeled VFD/Blower (Section 2.10.11).
•
If On Board Boiler Sequencing Technology (BST) is enabled, the Analog Output
terminals are used to drive the isolation valve, open and closed.
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When the 4-20mA is selected for the Analog Output, the 0-10VDC is disabled at the
VFD/Blower terminals, and the selected output is available at the terminals labeled
Analog /-.
2.10.9 RS-485 Comm Terminals
The RS-485 communication terminals (+, GND, & -) are used when the boiler plant is being
controlled by an Energy Management System (EMS) or AERCO Control System (ACS) using
Modbus (RS-485) communication.
2.10.10 RS-232 Comm Terminals
The RS-232 communication terminals (TxD and RxD) permit a laptop computer or other suitable
terminal to be connected to the boiler. The RS-232 communication feature permits viewing or
changing of Control Panel menu options and also provides access to data logs showing fault
and sensor log displays.
2.10.11 VFD/Blower (0-10 & AGND)
These terminals (0-10 & AGND) send an analog signal to control the blower speed. When any
of the 4-20mA options is selected for the Analog Outputs (Section 2.10.8), the output from the
VFD/Blower terminals is disabled.
2.10.12 Interlocks
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers or other accessories. These interlocks are called
the Remote Interlock and Delayed Interlock (REMOTE INTL’K IN and DELAYED INTL’K IN in
Figure 2-12). Both interlocks, described below, are factory wired in the closed position (using
jumpers).
NOTE
Both the Delayed Interlock and Remote Interlock must be in the
closed position for the unit to fire.
2.10.12.1
REMOTE INTL’K Terminals
The remote interlock circuit is provided to remotely start (enable) and stop (disable) the unit
if desired. The is 24 VAC and comes factory pre-wired closed (jumped).
2.10.12.2
DELAYED INTL’K Terminals (OUT & IN)
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers or other accessories. These interlocks are
called the Remote Interlock and Delayed Interlock ((REMOTE INTL’K IN and DELAYED
INTL’K IN in Figure 2-12). Both interlocks, described below, are factory wired in the closed
position (using jumpers).
