SAS | SAS Supply Air Sensor | EWC Controls

SAS Supply 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, UZC4 and UT3000 series control panels and senses the supply air temperature in both heating and cooling modes. Using the adjustable potentiometers or LCD menu 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 excessive temperature rise or fall during heating and cooling operations. EWC recommends mounting the SAS in the supply air plenum, approximately 6 - 12 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. Make sure you enable the SAS Dip switch on some panels. Now adjust the Heating and Cooling limit set points or Under/Over temperature Off-set values 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, measure the DC voltage at the SAS terminals on the Zone panel. Compare your voltage reading to the Table on page 2. You can also disconnect the SAS wire leads from the control panel and measure the sensor’s resistance. At room temperature (75F.) the ohm reading on a SAS will be approximately 10.5K ohms (10,500 ohms). You can also 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 SAS 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.