The ACI Platinum Copper Averaging Series features a copper sensing element with Etched Teflon colored lead wires to differentiate the different sensor types. The three-wire “-3W” option should be ordered when using with a 3-Wire temperature transmitter or sensor configuration on your building management system or PLC (Programmable Logic Controller). The purpose of the 3rd wire is to compensate for external lead wire resistance that will affect your sensor output. ACI recommends the use of 18 AWG lead wires to reduce the external lead wire resistance when using a Platinum RTD style sensor. The sensing element includes a continuous sensing element, which covers the entire length of the copper tube. This produces a better average temperature over the entire cross sectional area of your duct or unit when compared to a single point duct sensor or multi-point averaging sensor. These sensors are hermetically sealed to ensure that moisture and other contaminants won’t affect the reliability of the sensing element. The copper averaging sensor includes a foam pad to seal the duct and dampen vibrations once installed. The sensor length should be determined by the total cross sectional area of your duct. Standard enclosure options include the “-GD” galvanized or “-PB” plastic enclosure with hinged cover. Optional NEMA/IP rated weather proof enclosures and NIST Certificates are available as referenced in the ordering grid. For higher accuracies, see the A/TTM1K (Matched) Averaging transmitter Product Data Sheet. Applications: Roof Top Units, Air Handlers, Monitoring Duct Supply/Discharge/Return/Mixed Air