AERCO BMK 2.0 LN Dual Fuel Serial G-11-2402 and UP - Manual (Page 21)

CHAPTER 2: INSTALLATION
PR2: 04/22/13 Page 21 of 160
Benchmark 2.0LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
OMM-0052_0E
GF-127
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
applications), and the RS485 comm terminals in the I/O box. The wiring must be accomplished
using twisted-shielded pair wire from 18 to 22 AWG. Polarity must be maintained. For further
instructions and wiring diagrams, refer to the GF-108 Boiler Management System Operations
Guide and the CCP-1 data sheet (BMS 168 applications)/GF-131 and TAG-0050 (ACS
applications).
Figure 2-10. I/O Box Terminal Locations and Functions
2.10 I/O BOX CONNECTIONS
The types of input and output signals and devices to be connected to the I/O Box terminals
shown in Figure 2-10 are described in the following paragraphs.
NOTE
Older I/O PCBs are wired the same as new ones, even if silk-
screen designations differ.
NOTE
DO NOT make any connections to the I/O Box terminals labeled
“NOT USED”. Attempting to do so may cause equipment
damage.
Outdoor Sensor In
(1)
2.10.1
An outdoor air temperature sensor (AERCO Part No. 122790) will be required primarily for
the Indoor/Outdoor reset mode of operation. It can also be used with another mode if it is
desired to use the outdoor sensor enable/disable feature. This feature allows the boiler to
be enabled or disabled based on the outdoor air temperature.
The factory default for the outdoor sensor is DISABLED. To enable the sensor and/or select an