Nickel-Duct

Supported Applications

The ACI Nickel Duct Series is a single-point Nickel RTD temperature sensor designed for use with electronic controllers in commercial heating and cooling building-management systems. It is built for duct applications, with a 1/4" diameter stainless-steel probe carrying two 22 AWG etched-Teflon (PTFE) colored lead wires so the sensor type can be identified in the field.

ACI's proven double-encapsulation process and thermally conductive epoxy eliminate the effects of moisture and improve thermal response, making the sensor a reliable choice for supply, return and mixed-air duct measurement. For best accuracy the probe should be placed three to four duct segments downstream of any bend or obstruction, mounted on the top or sides of the duct in well-mixed air, and its wiring must never run in a conduit with line voltage.

Operating Conditions & Performance

The sensor is a Nickel RTD with a positive-temperature-coefficient (PTC) curve, a nominal output of 1000 Ohms at 21.1°C and Red/Red lead wires. It conforms to Din 43760 with a temperature coefficient of 6370 ppm/°C, and the sensing element is non-polarity sensitive.

The sensor operates over a range of -40 to 121°C. Accuracy is ±0.4°C at 0°C, ±0.17°C at 21.1°C, ±0.56°C at 54.4°C and ±1.25°C at 121°C. Sensor stability is 8 Seconds nominal, self-heating is 0.3°C/mW in still air, and the maximum operating current is 5 mA. Long-term drift is ±0.05% after 1000 Hours at 150°C.

The probe is 304 stainless steel with a 6.35 mm diameter, the lead wire is 22 AWG (0.65 mm), and the operating humidity range is 10 to 95% RH, non-condensing. Storage is rated -40 to 85°C, and the series is CE, RoHS2 and WEEE compliant with an optional NIST Certificate (3 Points).

Configuration Options

All variants share the same Nickel RTD element and accuracy; they differ by probe length and enclosure, which together set the duct reach and the environmental protection:

• Probe length — 4", 6", 8", 12" or 18" probes let the sensor reach the center of ducts of different widths.
• -GD Galvanized enclosure — galvanized steel, rated -40 to 115°C, NEMA 1 (IP10).
• -PB Plastic box — ABS plastic, UL94-HB, rated -30 to 90°C.
• -BB Bell box — aluminum, NEMA 3R.
• -4X enclosure — NEMA 4X (IP 66), rated -40 to 70°C for wash-down or damp locations.

Enclosure choice also changes the housing size; for example the plastic box (-PB) measures 91.44 mm x 121.55 mm x 59.80 mm, while the compact bell box (-BB) is 75 mm x 59.38 mm.

Key Product Differences

Models follow the configuration scheme A/1K-NI-D-<probe length>-<enclosure>, for example A/1K-NI-D-8"-GD-NIST. The catalog combines the five probe lengths with the four enclosures, including:

• A/1K-NI-D-4"-4X, A/1K-NI-D-4"-GD and A/1K-NI-D-4"-PB — 4" probe variants.
• A/1K-NI-D-6"-BB, A/1K-NI-D-8"-4X and A/1K-NI-D-12"-GD — mid-length probe variants.
• A/1K-NI-D-18"-4X, A/1K-NI-D-18"-BB and A/1K-NI-D-18"-PB — the longest 18" probe variants.

Each combination is available with or without a NIST Certificate, so the sensor can be specified precisely for the duct size, enclosure environment and traceability the installation demands.