AERCO BMK 2000DF - Manual (Page 28)

Benchmark 1500DF - 2000DF Boilers
CHAPTER 2 – INSTALLATION
Page 28 of 196 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0098_0A
04/01/2014 Ph.: 800-526-0288 GF-144
Figure 2-12: I/O Box Terminal Strips
2.10.1 Outdoor Air In (OUT)
& Air Sensor Common (COM)
The OUTDOOR AIR IN terminal is used for connecting an outdoor temperature sensor (AERCO
P/N 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 of the I/O PCB (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 PCB. The sensor end of the shield must be left free and
ungrounded.
When mounting the sensor, it must be located on the North side of the building where an
average outside air temperature is expected. The sensor must be shielded from direct sunlight
as well as impingement by the elements. If a shield is used, it must allow for free air circulation.