AC Gas Leak Sensor (Air Conditioner Refrigerant Leak Detector) — Split/VRF • Central AC • Heat Pump
Winsen® manufactures fixed AC gas leak sensors for residential and commercial air-conditioning systems. We cover A1 (R134a, R410A, R404A), A2L (R32, R454B, R1234yf/ze) and A3 (R290, R600a) gases. Choose NDIR for ppm early warning or MOS/NDIR 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
Model Guide — 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 (NDIR-LEL or MOS)
- Relays for ventilation & shutdown interlocks
- IP options for plant rooms and cold spaces
What is an AC Gas Leak Sensor?
An AC gas leak sensor is a fixed, electronic detector that continuously measures refrigerant concentration around air-conditioning equipment and automatically drives alarms and interlocks (ventilation, fan/indoor-unit shutdown). It complements handheld detectors 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 from heavy condensation/dust (filters/enclosure) |
| MOS (Semiconductor) | A2L/A3 %LEL | 0–100% LEL | Fast response; robust; cost-effective | Cross-sensitivities possible; periodic calibration advised |
| Catalytic Bead | General hydrocarbons (A3) | 0–100% LEL | Mature tech for flammables | Requires O₂; susceptible to poisons (silicones/lead) |
Typical AC 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, expansion valves, and floor low spots/sumps; use IP-rated enclosures and BMS interlocks.
Line sets, condenser & evaporator sections
Monitor around brazed joints, service valves, manifolds; avoid strong supply streams that could bypass the sensor.
Heat pumps & general HVAC equipment
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/NDIR-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) |
Placement & Setpoints — Good Practice
- Mounting height: Most AC refrigerants are heavier than air ⇒ mount low; confirm with on-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 design spec.
- Interlocks: Pre-alarm → ventilation; Main → equipment shutdown + beacons/horns/BMS events.
Finalize thresholds and quantities against local codes and your project specification.
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.
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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 — Infrared (NDIR) Refrigerant Leak Sensors
How many sensors do I need per room?
Plan ~5–10 m radius coverage per sensor in open rooms. Add units near indoor units, valves, joints, and floor-level pockets where gas may accumulate. Irregular layouts typically need more sensors.
What alarm thresholds should I use?
For A2L/A3 gases: pre-alarm ≈25% LFL to start ventilation; main ≈50% LFL to trip equipment and trigger beacons/horns. For A1 gases, use ppm bands (e.g., 1,000–5,000 ppm) per project spec and risk assessment.
Where should the sensor be mounted?
Most AC refrigerants are heavier than air; mount low (≈150–300 mm above floor) near likely leak sources and pooling points. Avoid strong supply air that could bypass the sensor. Probe/duct versions can monitor return air.
How often should I calibrate and bump-test?
Typical calibration is every 12–24 months with periodic bump tests (quarterly/biannual). Dusty or humid sites, or areas with cleaning aerosols, may need more frequent checks and filter maintenance.
Which technology should I choose: NDIR or MOS?
Choose NDIR for ppm early warning and long-term stability; choose MOS or IR-LEL for %LEL safety interlocks on A2L/A3 systems. Many sites use both tiers for redundancy.
Can Winsen customize for OEM/volume programs?
Yes—ranges, firmware, Modbus mapping, connectors/harnesses, housings (IP rating), labels/branding, and packaging can be tailored for volume deployments.
