RH-Combo-Duct-Nickel

Supported Applications

The ACI Relative Humidity Duct with Nickel Sensor series is a relative humidity transmitter designed for commercial heating and cooling building management systems. The unit features a thermoset polymer capacitive sensing element with a factory-fitted hydrophobic filter, providing resistance to dust, dirt, oils, and common environmental chemicals found in duct environments.

Operating Conditions & Performance

The series measures relative humidity from 0-100% RH within an operating range of 0 to 95% RH (non-condensing). Accuracy is specified as +/- 1% over a 20% RH Range between 20 to 90%, or +/- 2% and +/- 3% from 10 to 95%. The device operates within an ambient temperature range of -40 to 140 °F (-40 to 60 °C) with a storage temperature range of -40 to 149 °F (-40 to 65 °C). Stability is rated at less than 2% drift over 5 years, and the typical response time (T63) is 20 seconds.

Power requirements vary by output configuration: 4-20 mA requires 15 - 40 VDC / 18 - 28 VAC for a 250 Ω load or 18 - 40 VDC / 18 - 28 VAC for a 500 Ω load. The 0-5 VDC output requires 12 - 40 VDC / 18 - 28 VAC, while the 0-10 VDC output requires 18 - 40 VDC / 18 - 28 VAC.

Configuration Options

The series supports multiple enclosure configurations and sensor options to accommodate specific installation needs:

• Housing & Enclosure Ratings: Available in Euro (-EH) enclosures made of ABS Plastic (UL94-V0), NEMA 4X (-4X) enclosures made of Polystyrene Plastic (UL94-V2, IP 66), and NEMA 3R (-BB) aluminum plenum-rated enclosures.
• Process Connections & Wetted Materials: The -EH enclosure utilizes a 0.75" (19.05 mm) diameter sensing tube made of 304 Series Stainless Steel with a stainless steel filter or optional sintered filter. The -4X and -BB enclosures use Schedule 40 PVC (White) tubes; the -4X features slotted PVC without a filter, while the -BB also uses slotted PVC.
• Output Signals: Factory default is 2-wire 4-20 mA. Field-selectable options via on-board DIP switches include 3-wire 0-5 VDC or 0-10 VDC, and the ability to output both voltage and current signals.
• Sensor Elements: Includes a Nickel RTD (PTC) temperature sensor with Din 43760 standard compliance. The RH sensor type is capacitive with a hydrophobic filter.
• Calibration & Verification: Units include on-board DIP switches for field calibration and test points at 0%, 50%, and 100% to verify operation. Three-point NIST Calibration Certificates are available as an option, or five-point certificates within a selected 20% range.

Key Product Differences

Variants in this series differ primarily by accuracy class and enclosure type:

• Accuracy Options: Models are configured for +/-1% (RH1), +/-2% (RH2), or +/-3% (RH3) relative humidity accuracy.
• Enclosure Configurations: The "D" suffix denotes the Euro (-EH) enclosure. The "-4X" suffix indicates the NEMA 4X Polystyrene housing, and the "-BB" suffix specifies the aluminum NEMA 3R plenum-rated housing.
• NIST Certification: Specific SKUs include a "NIST" designation indicating the inclusion of a three-point calibration certificate.