HVAC Leak Sensor (Refrigerant Leak Detector) for VRF/VRV, Chillers & Heat Pumps
Winsen® HVAC leak sensors provide continuous monitoring of A1, A2L, and A3 refrigerants across hotels, offices, data centers, supermarkets, and industrial plants. Choose NDIR for ppm early warning and MOS/NDIR for %LEL safety alarms—ready for BMS/PLC via 4–20 mA, RS-485 Modbus, and relay outputs.
Why an HVAC Leak Sensor?
- Early warning: Detect ppm-level leaks before nuisance trips or occupancy impact.
- Safety interlocks: Use %LFL thresholds to trigger ventilation and equipment shutdown.
- Compliance support: Implement good-practice monitoring for VRF hotels, chiller rooms, and public spaces.
- BMS/PLC integration: Standard analog, Modbus, and relay outputs fit existing control schemes.
NDIR Refrigerant Sensor
Semiconductor Refrigerant Sensor
Technology Comparison
| Technology | Best For | Range | Advantages | Considerations |
|---|---|---|---|---|
| NDIR | A1 ppm; A2L ppm/%LEL | ppm → %LEL | High selectivity, low drift, long life | Higher upfront cost; avoid heavy condensation/dust (use filters/enclosures) |
| MOS | A2L/A3 %LEL | 0–100% LEL | Fast response, robust, cost-effective | Cross-sensitivity; periodic calibration recommended |
| Catalytic Bead | General hydrocarbons | 0–100% LEL | Mature, widely used | Needs O₂; can be poisoned by silicones/lead |
Placement & Setpoints (HVAC Good Practice)
- Mounting height: Most refrigerants are heavier than air → mount low; verify with room airflow.
- Coverage: Typical radius 5–10 m per sensor in open rooms; add units near likely sources (valves, joints).
- Setpoints: A2L/A3 often use %LFL bands (e.g., pre-alarm ~25% LFL; main ~50% LFL). A1 commonly uses ppm tiers (e.g., 1,000–5,000 ppm depending on design).
- Interlocks: Pre-alarm → ventilation; Main alarm → equipment shutdown + alarm notification.
Finalize thresholds and quantities against your project specification and local codes.
Typical HVAC Applications
VRF/VRV indoor units & hotel rooms
Mount low (~150–300 mm above floor) near indoor units and pooling points. Tie alarms to fan shutdown and fresh-air purge; choose ppm or %LEL setpoints per spec.
Chiller & machinery rooms, compressor racks
Place near compressors, oil separators, valves, and low spots/sumps. Use IP-rated enclosures and BMS interlocks: pre-alarm → purge; main alarm → trip plant.
Cold storage & refrigerated display cases
Install under cases and along manifolds/pipe runs. Select low-temperature, condensation-resistant housings; alarms can start extract and close night curtains.
Data center in-row/CRAC units
Position in return-air paths, beneath raised floors, and near coils. PPM early warning protects personnel and uptime; integrate shutdown and ventilation override.
Heat pump & general HVAC equipment
For A2L/A3, monitor near compressors/valves and in return air; use %LFL interlocks for safe shutdown. Weatherproof housings for outdoor units.
Core Specifications (Typical)
| Parameter | Value / Option |
|---|---|
| Power Supply | 12–24 VDC (others on request) |
| Outputs | 4–20 mA (2/3-wire), RS-485 Modbus RTU, 1–2× relays (N.O./N.C.) |
| Measurement Ranges | ppm (NDIR) and/or %LEL (MOS/NDIR), customizable by gas |
| Response Time (T90) | ≤ 20–30 s typical |
| Operating Temp/Humidity | -20 to +50 °C; 15–95% RH non-condensing (model dependent) |
| Ingress Protection | Up to IP65 with optional enclosure |
| Compliance | CE, RoHS; designed for integration with BMS/PLC |
Sensor Technologies: NDIR vs. MOS
| Feature | NDIR (Infrared) | MOS (Semiconductor) |
|---|---|---|
| Accuracy | High (±2% FS) | Moderate (±5% FS) |
| Response Time | 1–3 seconds | <1 second |
| Power Consumption | <25 mW | <50 mW |
| Lifetime | >5 years | 2–3 years |
| Cost | Higher | Lower |
| Best Use | Safety-critical HVAC & commercial | Low-cost appliances |
Recommendation for Oman:
For large-scale and safety-critical systems like district cooling, hotels, and cold storage, choose NDIR technology. For home appliances and low-cost products, MOS sensors provide a cost-effective alternative.
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.
Compliance & Best-Practice Notes
Our engineering team helps you align sensor selection and placement with widely referenced safety frameworks for refrigeration/HVAC (e.g., A-series refrigerant classifications, machinery-room requirements, and A2L deployment guidelines). Implementation details vary by country and project—please share your specification so we can propose a compliant solution.
Installation, Commissioning & Maintenance
- Commissioning: Verify outputs, alarms, and interlocks; label setpoints.
- Calibration: Typical 12–24 months; bump test during maintenance.
- Spares: Keep 10–15% spare modules for critical facilities.
FAQs — Refrigerant Leak Sensors & Detectors
What is the difference between a sensor and a detector?
In HVAC, a fixed device is often called a “sensor” or “detector” interchangeably. Handheld tools used by technicians are typically called “leak detectors.”
Which technology should I choose for A2L refrigerants like R32 or R454B?
Use NDIR for ppm-level resolution and stability, or MOS/NDIR %LEL for safety alarms based on LFL percentages. Many projects use both: ppm early warning + %LEL shutdown.
Where should sensors be mounted for refrigerants?
Most refrigerants are heavier than air—mount low, near leak sources and where gas could accumulate. Validate with airflow studies and site conditions.
How often do sensors need calibration?
Typical intervals are 12–24 months depending on technology and environment. Critical sites may choose more frequent bump tests.
Do you support BMS/PLC integration?
Yes. Standard outputs include 4–20 mA, RS-485 Modbus RTU, and relay contacts.
Can you customize for OEM projects?
Absolutely. We support custom ranges, firmware, connectors, harnesses, branding, and private-label packaging for volume customers.
