Instruction Manual

Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
Page 28 of 192 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0082_0J
05/21/2014 Ph.: 800-526-0288 GF-130
DO NOT make any connections to the I/O Box terminals labeled
“NOT USED”. Attempting to do so may cause equipment
damage.
Figure2-12: I/O Box Terminal Strips
2.10.1 OUTDOOR AIR IN Terminals
The OUTDOOR AIR IN terminal is used for connecting an outdoor temperature sensor (AERCO
Part No. GM-123525), as 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
enable/disable outdoor temperature, see the Configuration menu in Chapter 3.
The outdoor sensor may be wired up to 200 feet from the boiler. It is connected to the
OUTDOOR AIR IN and AIR SENSOR COMMON terminals in the I/O Box (see Figure 2-12).
Wire the sensor using a twisted shielded pair wire from 18 to 22 AWG. There is no polarity to
observe when terminating these wires. The shield is to be connected only to the terminals
labeled SHIELD in the I/O Box. The sensor end of the shield must be left free and ungrounded.
CAUTION