Option 3 - Outdoor Reset With Direct Wired Header Sensor And Direct Wired Outdoor Sensor - Watts Aerco BENCHMARK 750 User Manual

Benchmark 750 – 1000 Boiler User Manual - INTERNATIONAL
CHAPTER 9. BOILER SEQUENCING TECHNOLOGY
9.3.3 Option 3 - Outdoor Reset with DIRECT WIRED Header Sensor AND DIRECT
WIRED Outdoor Sensor
NOTE: Both Header Sensor AND Outdoor Sensor must be wired.
Step 1 - Direct Wired Header Sensor Wiring
1. On the MASTER Unit, connect the Header Temperature Sensor (P/N 61040) to the Feed Forward
(FFWD) terminals on the P-1 Harness Via the terminal block labeled Header Temp sensor in the I/O
Box.
NOTES: The header sensor must be installed between 2 and 10 (0.61 and 3.1m) feet
downstream of the LAST Heating Boiler in the plant's supply water header. Shielded pair 18 - 22
AWG cable is recommended for header sensor wiring. There is no polarity to be observed. The
ground for the shield is at the "SHLD" terminal in the I/O the Box. The sensor end of the shield
must be left free and ungrounded.
Temp Sensor P/N 61040
Step 2 - Direct Wired Outdoor Sensor
1. On the MASTER Unit, Connect the Outdoor Temperature Sensor (P/N 123525) to the "OUT" and
"COM" terminals in the I/O Box.
NOTES:
•
Twisted shielded pair 18 - 22 AWG cable is recommended for header sensor wiring. There is no
polarity to be observed. The ground for the shield is at the "SHLD" terminal in the I/O the Box. The
sensor end of the shield must be left free and ungrounded.
•
When mounting the Outdoor 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 rain and snow. The outdoor sensor may be wired up to 200 feet (61m) from the Heating Boiler.
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11/03/2016
Header Temp Sensor
Temp Sensor P/N 123525
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
I/O Box
OMM-0119_0A
GF-130-I