Product Overview

Model SAS
(Supply/Return Air Sensor)
The “SAS” Supply Air Sensor allows precise real time monitoring of the Supply Air temperature on your Zoned HVAC
system. The SAS wires directly into the BMPlus, NCM300, EWC-300 or UZC series control panels and senses the
supply air temperature in both heating and cooling modes. Using the adjustable potentiometers on the control panel, the
installer can set the desired temperature limit set points on most EWC zoned HVAC systems. This will protect the HVAC
equipment from frozen coils, excessive sweating, or short cycling the furnace/heat pump on high limit or pressure.
EWC recommends mounting the SAS in the supply air plenum, approximately 12 -18 inches downstream of the Heat
Exchanger or DX coil. Upstream of the Electric strip heating elements in heat pump applications. It should also be
installed upstream of any Bypass duct connection. Some EWC Control panels have dual high limit potentiometers which
allows mounting the SAS in the discharge plenum, regardless of the DX coil and/or heat exchanger or strip heat
configuration.
Be sure to remove the factory supplied resistor on the Supply Air Sensor terminal block of the Ultra Zone panel, and
connect the field wiring to those terminals instead. On some panels, make sure you enable the SAS Dip switch. Now dial
in the Heating and Cooling limit set points for your particular application on the Ultra Zone Control panel and enjoy real
time monitoring of the HVAC supply air temperature in heating and cooling modes.
The Sensor wiring is not polarity sensitive. SAS equipped panels have a designated terminal block for the SAS. To test an
SAS, disconnect the wire leads from the control panel and remove it from the duct. At room temperature (75F.) the ohm
reading on a SAS will be approximately 10.5K ohms (10,500 ohms). Or leave the SAS in the duct and insert a separate
temperature probe of known accuracy in the same location as the SAS and measure the SAS resistance against the table
provided on page 2. You should measure a value within 5% of the table value and the separate temperature probe.
The SAS can also be used as a Return Air sensor on the HK2000 Economy Control System and the UZC4 Zone
Control system. When being used to monitor return air, EWC recommends mounting the RAS in the return plenum,
downstream from the bypass damper between the bypass and the air handler. This is done to ensure the air being sensed
is a proper mix of bypassed air and return air. Refer to the HK2000 and the UZC4 Technical Bulletins for the specific
Return Air Features & Functions provided, when the SAS is used as a Return Air Sensor.
2”
2”
1”
5 3/4” INSERTION
5/16”
DIAMETER
The “SAS” is constructed of UV stabilized Poly Carbonate
Plastic with seamlessaluminum tubing frame and a highly
accurate thermistor with 24AWG 12” leads. The unique
construction provides a thermal barrier between the
temperature probe and the duct work allowing precise air
temperature measurements.
CONTROLS INC.
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EW
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Forced Air Zone Controls
®
385 Hwy. 33
Englishtown, NJ 07726
Ph: 800-446-3110
Fx: 732-446-5362
P/N 090377A0072 REV. B 04.09.10
CONTROLS INC.
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W
Excellence Without Compromis
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