User Manual

GF-123 Benchmark 2.0LN Low NOx Boiler Chapter 2
OMM-0046_0F Installation, Operation and Maintenance Manual Installation
PR1 10/17/12 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 Page 25 of 172
2.9.4 Remote Setpoint and Direct Drive Modes
The Benchmark 2.0LN Boiler can accept several types of signal formats from an Energy
Management System (EMS), Building Automation System (BAS) or other source, to control
either the setpoint (Remote Setpoint Mode) or air/fuel valve position (Direct Drive Mode) of the
Boiler. These formats are:
• 4 to 20 mA/1 to 5 VDC
• 0 to 20 mA/0 to 5 VDC
• PWM – (Pulse Width Modulated signal. See para. 2.10.4)
• Network (RS485 Modbus. See para. 2.10.7)
While it is possible to control a boiler or boilers using one of the previously described modes of
operation, it may not be the method best suited for the application. Prior to selecting one of
these modes of operation, it is recommended that you consult with your local AERCO
representative or the factory for the mode of operation that will work best with your application.
For more information on wiring the 4 to 20 mA / 1to 5VDC or the 0 to 20 mA / 0 to 5 VDC, see
paragraph 2.9.3.
2.9.5 Combination Mode
NOTE
Only BMS Model 168 and ACS can be utilized for the Combination Mode,
not the BMS II (Model 5R5-384).
With a Combination Mode unit, field wiring is between the unit’s I/O Box wiring terminals, the
CCP (Combination Control Panel), and the BMS (Boiler Management System). For ACS
applications, the wiring is between the ACS panel, the ACS Relay panel (optional, depending on
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).