AERCO BMK 1500-2000 - Manual (Page 127)

Benchmark 1500 - 2000 Boilers
CHAPTER 10. BOILER SEQUENCING TECHNOLOGY
OMM-0097_0D AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 127 of 188
GF-142
Ph.: 800-526-0288
10.3.7 Option 7 - Remote Setpoint with MODBUS Header Sensor AND 4-20ma
Setpoint Drive
NOTE: Both Header Sensor AND 4-20ma Direct Drive must be wired. See the C-More Controller User
Manual, OMM-0032, GF-112 and ProtoNode User Manual, OMM-0080, GF-129 for more information.
Step 1: MODbus Header Sensor
1. Using Shielded pair 18 - 22 AWG cable, Connect the Temperature Transmitter (AERCO P/N 65169)
terminal Pin B to the RS485+ terminal on the I/O Box of any of the Boiler units, and Pin A of the
Temperature Transmitter to the RS485- terminal on the I/O Box of any of the Boiler units.
2. Using Shielded pair 18 - 22 AWG cable, connect the Modbus Header Temperature Sensor (AERCO
PN 24410) to pins 2 and 3 of the Temperature Transmitter.
3. Install a jumper wire between pins 1 and 2 of the Temperature Transmitter.
NOTES:
• Polarity must be observed for the RS485 connections. The ground for the shield is at the “SHLD”
terminal in the I/O the Box.
• The header sensor must be installed between 2 and 10 feet downstream of the LAST boiler in the
plant’s supply water header.
• There is no polarity to be observed. The ground for the shield is at the power supply ground. The
sensor end of the shield must be left free and ungrounded.
Step 2: Direct Wired 0-20ma or 4-20ma Wiring
1. Connect the 4-20ma or 0-20ma terminals from the Direct Drive source to the Ain+ and Ain- terminals
on the Master.
NOTES:
• Unit’s I/O Box. Shielded pair 18 - 22 AWG cable is recommended for this connection. Polarity must
be observed.
• The ground for the shield is at the driver signal source.
Temp Sensor PN 24410 Modbus Transmitter I/O Box
I/O Box