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RTD-Flexible-Ave
Platinum RTD Flexible Averaging
- The flexible averaging sensor measures across multiple points to produce a better duct air average than a single-point duct sensor.
- The product uses a 1K ohm platinum RTD with Class A tolerance, DIN EN 60751 reference, and a 3850 ppm per deg C temperature coefficient.
- The A/1K-2W-FA series is listed as two-wire and non-polarity-sensitive, with controller wiring connected to analog input leads.
- The flexible sensor uses low-smoke PVC cable rated CL2P or CMP, with a 0.170 in nominal cable diameter and dual-wall adhesive heat shrink at sensing elements.
- Ordering supports galvanized, plastic, aluminum bell box, and NEMA 4X enclosure options for different mounting and protection needs.
- Flexible averaging is limited to 0 to 75 deg C operation, 10 to 90% non-condensing humidity, and applications that do not require UV, chemical, or high-humidity resistance.
- Use the sensor across large air-handler duct sections where stratification makes a single-point reading less representative.
- Use flexible averaging in rooftop HVAC ductwork when the operating temperature and humidity stay inside the flexible sensor limits.
- Use a crisscross duct pattern to average mixed air streams and reduce error from hot and cold layers.
- Place the averaging element downstream of fan discharge where the airstream is more uniform across the duct cross-section.
- Use the sensor where return duct temperature needs a broad representative average instead of a local point sample.
- Applications where averaged air temperature feedback can support tighter HVAC control.
Product Overview
- Accuracy +/- 0.06% Class A
- Accuracy Detail (Tolerance Formula: +/- ºC = (0.15ºC + (0.002 *
- Alloy Material (-) Copper
- Alloy Material (+) Copper
- Approvals DIN EN 60751 (IEC 751)
- Cable Diameter 0.17 in
- Cable Material PVC
- Electrical Connection Pigtail Leads
- Enclosure Ratings NEMA Type 4X
- Fitting Polyamide 66 (High Performance Nylon)
- Insulation Etched Teflon (PTFE) Colored Leads
- Operating Current 3 mA
- Operating Humidity 10 to 95% RH, non-condensing
- Operating Temperature, Max 150 °C
- Operating Temperature, Min -40 °C
- Output Detail Sensor Output @ 0ºC (32ºF): 1000 Ohms nominal
- Response Time 15 Seconds nominal
- Self Heating Effect 4 mW / °C
- Series ID RTD-Flexible-Ave
- Sheath Material 304 Stainless Steel
- Stability +/- 0.03% after 1000 Hours @ 300ºC (572ºF)
- Storage Temperature, Max 75 °C
- Storage Temperature, Min -20 °C
- Temperature Coefficient DIN EN 60751 (IEC 751)
- Temperature Measurement Range -40 to 115°C
- Temperature Sensor Type 100 Ω 2 Wire Platinum RTD
- Tolerance +/- 0.06% Class A
- Tube Length 4.5 in
- Wire Gauge 22 AWG
Supported Applications
The ACI Platinum Flexible Averaging Series is a multi-point temperature sensor designed for use with electronic controllers in commercial heating and cooling building management systems. The series provides an average temperature reading of air inside ducts, offering improved accuracy compared to single-point sensors. Documented applications include Air Handlers, Roof Top Units, Mixed/Discharge or Supply/Return Air Monitoring, Data Centers, and Hospitals.
Operating Conditions & Performance
The series utilizes a Platinum RTD sensor with a PTC (Positive Temperature Coefficient) curve conforming to DIN EN 60751 (IEC 751), featuring a temperature coefficient of 3850 ppm / °C. The operating and storage temperature range is -20 to 75°C (-4 to 167°F). Operating humidity must remain within 10 to 90% RH, non-condensing.
Accuracy varies by sensor length at 20°C (68°F):
- 8' Length: +/- 0.34°C (+/- 0.62°F)
- 12' Length: +/- 0.45°C (+/- 0.81°F)
- 24' Length: +/- 0.80°C (+/- 1.44°F)
The sensor tolerance is specified as +/ - 0.06% Class A, with a stability of +/ - 0.03% after 1000 Hours @ 300°C (572°F). Response time for a 63% step change is 15 Seconds nominal.
Configuration Options
The series supports flexible configurations with sensing points determined by length: four sensing points on 8' and 12' models, and nine sensing points on 24' & 50' models. The sensor jacket is Low Smoke PVC rated as CL2P or CMP Plenum Rated Cable with a nominal diameter of 0.170" (4.32mm). Electrical connections utilize an 18 AWG plenum-rated cable with Etched Teflon colored lead wires; the internal conductor material is Silver Plated Copper.
Enclosure options include:
- -GD Enclosure: Galvanized Steel, NEMA 1 (IP10)
- -PB Enclosure: ABS Plastic, UL94-HB, Plenum Rated
- -BB Enclosure: Aluminum, NEMA 3R (IP 14)
- -4X Enclosure: Polystyrene Plastic, UL94-V2, NEMA 4X (IP 66)
The series is available with optional accessories including a Copper Capillary Mounting Clip (Item #130525), Universal Plastic Mounting Clips (Item #145421 or Item #145430). NIST Certificates are also offered as an option.
Key Product Differences
The Platinum Flexible Averaging Series is distinct from the broader ACI Averaging family which includes Copper and Thermistor variants. This specific series uses a 1K Ohm nominal output at 0°C (32°F) with two wires that are non-polarity sensitive. The flexible construction limits use to applications where operating temperatures do not exceed 75°C, high humidity is controlled, chemical resistance is not required, and UV Light Air Treatment Systems are absent; the outer cable jacket lacks a UV protectant.
Installation requires placing the entire length of the sensor coil inside the duct. When installing near air-handling units, place the sensor downstream from the fan discharge. The series carries RoHS2 and WEEE approvals and is covered by ACI's Five (5) Year Limited Warranty.
PDFs & Manuals
