AC Refrigerant Sensor (Leak Detector) — Split/VRF • Central AC • Heat Pump
Winsen® electronic AC leak sensors provide continuous, fixed monitoring for air-conditioning refrigerants across residential and commercial buildings. We support A1 (R134a, R410A, R404A), A2L (R32, R454B, R1234yf/ze) and A3 (R290, R600a) gases. Choose NDIR for ppm early warning or MOS/IR-LEL for %LEL safety interlocks—ready for BMS/PLC via 4–20 mA, RS-485 Modbus, and relay outputs.
- A1 / A2L / A3 Coverage
- NDIR ppm & MOS %LEL
- OEM/ODM • Bulk Orders
- Fast Lead Time
Pick by Refrigerant Class & Measurement
A1 (R410A / R134a) — NDIR PPM
- Typical ranges: 0–1,000 / 0–5,000 ppm
- Outputs: 4–20 mA, RS-485 Modbus, 1–2 relays
- T90 ≤ 30 s • Low drift, long life
A2L (R32 / R454B / R1234yf/ze) — NDIR PPM / %LEL
- PPM early warning and/or 0–100% LFL/LEL
- 4–20 mA / RS-485 / relays
- VRF/VRV rooms & hotel guestrooms
A3 (R290 / R600a) — %LEL Safety
- Range: 0–100% LEL (IR-LEL or MOS)
- Relays for ventilation & shutdown interlocks
- IP options for plant/mechanical rooms
What is an AC Refrigerant Sensor?
An AC refrigerant sensor is a fixed, electronic detector installed near AC equipment to measure refrigerant concentration and automatically trigger alarms and interlocks (ventilation, unit shutdown). It complements handheld sniffers used by technicians for pinpoint leak search.
NDIR Refrigerant Sensor
Semiconductor Refrigerant Sensor
Technology Options
| Technology | Best For | Range | Advantages | Considerations |
|---|---|---|---|---|
| NDIR (Infrared) | A1 ppm; A2L ppm/%LEL | ppm → %LEL | High selectivity & stability; not O₂-dependent; long life | Protect optics from condensation/dust (filters/enclosures) |
| MOS (Semiconductor) | A2L/A3 %LEL | 0–100% LEL | Fast response; robust; cost-effective | Possible cross-sensitivities; periodic calibration advised |
| Catalytic Bead | General hydrocarbons (A3) | 0–100% LEL | Mature technology | Needs O₂; can be poisoned by silicones/lead |
Typical Applications
Split/VRF indoor units & hotel rooms
Mount low (~150–300 mm above floor) near indoor units and pooling points. Pre-alarm → fresh-air purge; main alarm → fan/indoor-unit shutdown.
Central AC (AHU/MAU) & mechanical rooms
Place near coils, TXVs, service valves, and floor low spots/sumps; use IP-rated housings and BMS interlocks.
Line sets & evaporator/condenser sections
Monitor around brazed joints, manifolds; avoid strong supply streams that could bypass the sensor.
Heat pumps
For A2L systems, use %LFL tiers (≈25% pre-alarm; ≈50% main) to trigger ventilation and safe shutdown.
Core Specifications
| Parameter | Value / Option |
|---|---|
| Measurement | NDIR ppm and/or %LFL (MOS/IR-LEL) |
| Outputs | 4–20 mA (2/3-wire), RS-485 Modbus RTU, 1–2 relays (N.O./N.C.) |
| Response Time (T90) | ≤ 20–30 s typical |
| Supply | 12–24 VDC (others on request) |
| Operating Conditions | −20…+50 °C; 15–95% RH non-condensing (model-dependent) |
| Enclosures | Wall, panel, duct; housings up to IP65 |
| Compliance | CE & RoHS; designed for BMS/PLC integration |
Placement & Setpoints — Good Practice
- Mounting height: Most AC refrigerants are heavier than air ⇒ mount low; verify with site airflow.
- Coverage: ~5–10 m radius per sensor in open rooms; add units near valves/joints and low pockets.
- Alarms: A2L/A3: pre-alarm ≈25% LFL; main ≈50% LFL. A1: ppm bands (e.g., 1,000–5,000 ppm) per project spec.
- Interlocks: Pre-alarm → ventilation; Main → equipment shutdown + beacons/horns/BMS event.
Finalize thresholds and quantities against your project specification and local codes.
Why Global Clients Choose Us?
The company consistently adheres to the quality policy of “Fine Craftsmanship, Scientific Innovation, Pursuit of Excellence, and Value-Added Service.” By formulating production process control plans and work instructions, it has established a standardized, accountable, and regulated process management system. Additionally, the company has independently developed an MES production management system, enabling comprehensive and visual management across the entire workflow.
30+ YEARS OF EXPERIENCE
R&D, manufacture and sales of sensors and sensing solutions.
QUALITY GUARANTEE CONTINOUS IMPROVEMENT
Complete and rigid process flow control, coupled with significant improvements.
INTERNATIONAL MARKET
Deliver sensing products to more than 100 countries and regions.
STABLE SUPPLY CHAIN RELIABLE PRODUCTION
Core components not subject to constraints, advanced equipments for manufaturing and test.
R&D STRENGTH TECHNOLOGY INNOVATION
200+ patents, 180+ R&D team members, self-built labs for continous innovation.
ONE-STOP SERVICE
Professional consultation, fast delivery, 24 hours after-sales support.
Leading the Industry, Innovative & Controllable Technology
With robust R&D capabilities, we maintain sustained input in R&D and unwavering commitment to technological innovation. This not only ensures that we remain at the forefront of industry but also drives continuous innovation, leading the future trend of the sensing industry.
FAQs — Freon Gas Sensors
How many sensors are needed in a guestroom or office?
Plan ~5–10 m radius coverage per sensor in open rooms. Add units near indoor units, valves, joints, and floor-level pockets where gas can accumulate. Irregular layouts typically need more sensors.
Should I choose ppm or %LEL measurement?
Use ppm (NDIR) for early warning and comfort/process monitoring; use %LEL (MOS or IR-LEL) to drive safety interlocks for A2L/A3 systems. Many projects deploy both.
Where exactly should sensors be mounted?
Most AC refrigerants are denser than air; mount low (≈150–300 mm AFF) near likely leak sources and pooling points. Avoid strong supply air. Duct/return versions can monitor airflow.
How often do I need calibration and bump tests?
Typical calibration is every 12–24 months with periodic bump tests (quarterly/biannual). Dusty/humid or aerosol-rich sites may need more frequent checks and filter maintenance.
What causes false alarms or cross-sensitivity?
Solvents/aerosols (silicone sprays, alcohol cleaners, paints) can affect semiconductor elements; heavy condensation/dust can obstruct optics. Use IP-rated housings, splash/dust guards, and good placement.
Can Winsen customize for OEM/volume rollouts?
Yes—ranges, firmware/Modbus mapping, connectors/harnesses, housings (IP), labels/branding, and packaging are customizable for volume deployments.
