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HygroFlex HF3A Transmitters

HygroFlex HF3A Transmitter

The Rotronic HygroFlex3 Advanced (HF3A) represents the next generation of fixed-mount humidity and temperature transmitters. Engineered for heating, ventilation, air conditioning (HVAC), cleanrooms, and light industrial manufacturing, the HF3A blends industrial-grade durability with advanced digital connectivity.

Equipped with the upgraded Rotronic HygroMer® HT-1 humidity sensor and a precision Pt100 Class B temperature sensor, the series delivers high operational accuracy ±1.2 %RH / ±0.1 K23 °C, rapid 1-second measurement updates, and long-term signal stability.

Features

Every model in the HF3A family is built on a unified, high-performance platform:

  • Robust IP65 Enclosure: All models utilise a newly designed, industrial-grade polycarbonate (PC-ABS) housing rated to IP65, providing heavy resistance against dust and moisture ingress.
  • Integrated NFC Interface: Features built-in Near Field Communication (NFC), enabling touchless configuration, parameter scaling, and firmware checks directly via a smartphone or PC application, even when the device is completely unpowered.
  • Versatile Wiring & Output Topologies: * HF3A-2 (2-Wire): Loop-powered configuration with fixed 4-20 mA analogue output.
    • HF3A-3 (3/4-Wire Analogue): Actively powered, offering freely scalable current (4-20 mA) output.
    • HF3A-D (3/4-Wire Digital): Adds integrated native Modbus RTU over RS485 digital communications alongside analogue outputs.
  • Advanced Monitoring Options: Available with either a clean, un-displayed front layout featuring an operational status multi-colour LED, or an upgraded backlit LCD display mapping live values, trends, and alarms.

The HF3A series is segmented into three distinct physical variants to match specific infrastructure requirements.

1. Wall Mount Version (Fixed Short Probe)

  • Design: Features a short, rigid probe permanently fixed directly to the bottom of the enclosure body (122 x 172 x 40.5 mm overall envelope).
  • Application Profile: Ideal for open-air indoor placement, technical machinery rooms, cleanrooms, warehouses, and storage facilities.
  • Temperature Operational Limit: Specialised for standard indoor and ambient thermal zones. Measuring range is limited to -40 to 85 °C (restricted further to -10 to 60 °C} if configured with the local LCD display screen) due to the proximity of the probe to the transmitter housing.

2. Duct Mount Version (Immersion Probe)

  • Design: Features a long, rigid probe extending straight out the rear of the enclosure body (122 x 82 x 265.5 mm overall envelope) designed to penetrate deep into heavy airflow channels.
  • Application Profile: Tailored explicitly for active ventilation shafts, main HVAC air distribution ducts, and environmental control plenums.
  • Temperature Operational Limit: The immersion probe itself handles extended temperatures from -50 to 100 °C, while the main electronics housing remains mounted safely on the outside of the duct wall within standard ambient operation limits.

3. Remote Cable Version (2-Meter Cabled Probe)

  • Design: Separates the sensor probe completely from the main housing using a heavy-duty, 2-meter flexible electrical cable. The housing maintains a compact profile (122 x 82 x 40.5 mm) while the independent probe measures 144 x 15 mm.
  • Application Profile: Critical for extreme-reach scenarios, high-vibration equipment tracking, climatic chambers, or confined/inaccessible technical spaces where mounting the main housing directly is impossible.
  • Temperature Operational Limit: Similar to the duct unit, the remote probe can withstand extended extreme temperatures from -50 to 100°C}$, allowing the delicate transmitter housing and optional display to be placed safely outside the harsh microclimate.
HygroFlex HF3A Wall Mount Transmitter

HygroFlex HF3A Wall Mount Transmitter

The HF3A Wall Mounted Transmitter is engineered for fixed indoor installations where precise ambient climate monitoring is critical. Featuring a compact, rigid probe mounted directly to the bottom of the enclosure, this variant provides reliable relative humidity and temperature mapping for open-air rooms, manufacturing spaces, and controlled environments.

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HygroFlex HF3A Duct Mount Transmitter

HygroFlex HF3A Duct Mount Transmitter

Rotronic The HF3A Duct Mounted Transmitter is designed for direct immersion into ventilation shafts, primary HVAC air ducts, and environmental control plenums. Featuring a long, rigid rear-mounted probe (265.5 mm overall envelope), this variant provides precise, continuous monitoring of high-volume indoor airflows while keeping the main electronics housing safely outside the duct wall. Equipped with […]

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HygroFlex HF3A Transmitter with 2m Cable

HygroFlex HF3A Transmitter with 2m Cable

The HF3A Remote Cable Transmitter is designed for complex, restricted, or extreme-temperature installations where mounting a transmitter housing directly at the measurement point is impractical. The probe is separated from the transmitter body with a 2 meter flexible electrical cable.

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