Benchmark 6000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
Page
30
of
210
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0086_0D
03/20/14
Ph.: 800-526-0288
GF-133
2.10.2 COMBUSTION AIR Terminal
The COMBUSTION AIR terminal is used to monitor the combustion air temperature sensor. This
input is always enabled and is a “to view only” input that can be seen in the operating menu. The
sensor is an AERCO BALCO wire sensor Part No. 12449. A resistance chart for this sensor is
provided in APPENDIX C. This sensor is an active part of the combustion control system and
must be operational for accurate air/fuel mixing control.
2.10.3 O
2
SENSOR Terminals
The O2 SENSOR (–) and O2 SENSOR (+) terminals are used to connect an external oxygen
sensor to the I/O box. The O
2
concentration is displayed in the operating menu of the C-More
Control system after a 60 second warm-up period.
2.10.4 SPARK SIGNAL Terminals
The SPARK SIGNAL terminals are not in use on the Benchmark 6000.
2.10.5 ANALOG IN Terminals
The ANALOG IN terminals (+ and –) are used when an external signal is used to change the
setpoint (Remote Setpoint Mode) of the boiler.
Either a 4 to 20 mA /1 to 5 VDC or a 0 to 20 mA/ 0 to 5 VDC signal may be used to vary the set-
point or air/fuel valve position. The factory default setting is for 4 to 20 mA / 1 to 5 VDC, however
this may be changed to 0 to 20 mA / 0 to 5 VDC using the Configuration Menu described in
Chapter 3.
If voltage rather than current is selected as the drive signal, a DIP switch must be set on the
PMC Board located inside the Control Box. Refer to Appendix D of the C-More Control Panel
OMM, GF-112, for information on setting DIP switches.
All supplied signals must be floating (ungrounded) signals. Connections between the source and
the boiler’s I/O Box must be made using twisted shielded pair of 18–22 AWG wire such as
Belden 9841. Polarity must be maintained and the shield must be connected only at the source
end and must be left floating (not connected) at the Boiler’s I/O Box.
Whether using voltage or current for the drive signal, they are linearly mapped to a 40°F to 240°F
setpoint or a 0% to 100% air/fuel valve position. No scaling for these signals is provided
2.10.6 B.M.S. (PWM) IN Terminals
The two B.M.S. (PWM) IN terminals are only used to connect the legacy AERCO Boiler
Management Systems (BMS), which utilize a 12 millisecond, ON/OFF duty cycle and is Pulse
Width Modulated (PWM) to control valve position. A 0% valve position = a 5% ON pulse and a
100% valve position = a 95% ON pulse. Note that these connections cannot be used with the
ARECO Control System (ACS).
2.10.7 SHIELD Terminals
The two SHIELD terminals are used to terminate any shields used on sensor wires connected to
the unit. Shields must only be connected to these terminals.
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:
