Fan Coil Unit Stainless Steel Coil Tube — WA-V-102C3L30
1. Product Overview
The WA-V-102C3L30 is a precision-engineered stainless steel coil tube designed specifically for integration into Fan Coil Units (FCUs) within commercial and industrial HVAC (Heating, Ventilation, and Air Conditioning) systems. Manufactured by Wenzhou Jixing Metal Materials Co., Ltd., this product represents a high-performance thermal exchange component that delivers superior heat transfer efficiency, mechanical durability, and long-term corrosion resistance in demanding environmental control applications.
The WA-V-102C3L30 coil tube is classified under the product category of Coil Tubes (盘管) and is engineered to serve as the primary heat exchange medium within fan coil assemblies, facilitating the transfer of thermal energy between circulating refrigerant fluid and ambient air streams. Its design adheres to stringent international standards governing both material composition and dimensional tolerances, ensuring seamless compatibility with a wide range of FCU configurations.
2. Material & Properties
2.1 Base Material Composition
The coil tube is fabricated from Austenitic Stainless Steel, conforming to the chemical composition requirements of ASTM A269 and EN 10217-7. The alloy designation corresponds to SAE 304 / UNS S30408, a widely recognized grade for thermal applications due to its excellent balance of corrosion resistance, formability, and thermal conductivity.
- Carbon (C): ≤ 0.08%
- Chromium (Cr): 18.0 – 20.0%
- Nickel (Ni): 8.0 – 10.5%
- Manganese (Mn): ≤ 2.0%
- Silicon (Si): ≤ 1.0%
- Phosphorus (P): ≤ 0.045%
- Sulfur (S): ≤ 0.030%
- Iron (Fe): Balance
2.2 Mechanical Properties
- Tensile Strength (UTS): ≥ 520 MPa
- Yield Strength (0.2% Offset): ≥ 205 MPa
- Elongation at Break: ≥ 40%
- Hardness (Brinell): ≤ 201 HB
- Density: 7.93 g/cm³
2.3 Physical & Thermal Properties
- Thermal Conductivity (at 20°C): 16.3 W/(m·K)
- Thermal Conductivity (at 100°C): 16.3 W/(m·K)
- Specific Heat Capacity: 502 J/(kg·K)
- Coefficient of Thermal Expansion (20–100°C): 17.3 × 10⁻⁶ /K
- Electrical Resistivity (at 20°C): 0.72 μΩ·m
- Maximum Service Temperature: 870°C (oxidation resistance)
2.4 Corrosion Resistance
The austenitic microstructure of the 304-grade stainless steel provides outstanding resistance against atmospheric corrosion, aqueous environments, and mild chemical exposure. The passive chromium oxide film (Cr₂O₃) formed on the surface self-heals under oxidizing conditions, ensuring long-term integrity in HVAC fluid circuits containing treated water, glycol solutions, and low-concentration chemical additives.
3. Technical Specifications
| Parameter | Specification | Standard / Reference |
|---|---|---|
| Product Model | WA-V-102C3L30 | — |
| Product Category | Coil Tube for Fan Coil Units (FCU) | — |
| Material Grade | SAE 304 / UNS S30408 | ASTM A269, EN 10217-7 |
| Outer Diameter (OD) | 10.2 mm ± 0.15 mm | ISO 1307 |
| Wall Thickness | 1.0 mm ± 0.10 mm | ASTM A269 |
| Inner Diameter (ID) | 8.2 mm ± 0.20 mm | — |
| Coil Pitch (Row Spacing) | 30 mm ± 0.5 mm | — |
| Number of Rows | 3 (Triple-Row Configuration) | — |
| Tube Length per Circuit | Variable (customizable per FCU specification) | — |
| Surface Finish | Mirror Polish (Ra ≤ 0.4 μm) | ASTM A240 |
| End Treatment | Flared / Flat-Cut (per application requirement) | ASME B31.9 |
| Working Pressure | ≤ 1.6 MPa (232 psi) | ASME B31.9 |
| Hydrostatic Test Pressure | 2.4 MPa (348 psi) — 30 min hold | ASME B31.9 |
| Operating Temperature Range | -40°C to +120°C | — |
| Refrigerant Compatibility | R-22, R-407C, R-410A, R-134a, Glycol Solutions | ASHRAE 34 |
| Coil Configuration | Serpentine (Continuous Bend) | — |
| Minimum Bend Radius | ≥ 3D (30.6 mm) | — |
| Maximum Flow Velocity | ≤ 3.5 m/s | ASHRAE Handbook |
| Weight (per meter) | ≈ 0.178 kg/m | — |
| Standards Compliance | ASTM A269, ASME B31.9, EN 10217-7, ISO 1307, GB/T 12771 | — |
4. Manufacturing Process
4.1 Raw Material Procurement & Inspection
The manufacturing cycle commences with the procurement of certified stainless steel strip or seamless tube stock from accredited suppliers. Incoming material undergoes rigorous Non-Destructive Testing (NDT), including ultrasonic thickness measurement, visual inspection, and spectroscopic chemical analysis to verify compliance with ASTM A269 chemical requirements. Each batch is accompanied by a Mill Test Certificate (MTC) traceable to the heat number.
4.2 Cold Forming & Coil Winding
The tube is cold-formed into a serpentine coil configuration using precision roll-bending machinery equipped with CNC-controlled tooling. The bending process maintains a minimum bend radius of 3D to prevent wall thinning below acceptable limits and to avoid material stress concentration that could lead to fatigue failure. The coil pitch (row spacing) of 30 mm is maintained with ±0.5 mm tolerance through automated positioning systems.
4.3 Heat Treatment (Stress Relief)
Following forming, the coil tube assembly undergoes a stress-relief annealing process at 650–750°C in a controlled inert atmosphere (argon or nitrogen). This eliminates residual stresses introduced during cold forming, stabilizes the microstructure, and restores full mechanical properties. The process ensures the coil maintains dimensional stability throughout its service life.
4.4 Surface Finishing & Polishing
The exterior surface is subjected to a multi-stage polishing process to achieve a Mirror Finish (2BA / No. 7 surface) with surface roughness (Ra) ≤ 0.4 μm. This ultra-smooth surface minimizes fluid friction losses, reduces fouling potential, and enhances the aesthetic integration within visible FCU installations. The polishing process includes:
- Grit blasting (G180–G240) for surface preparation
- Electrolytic polishing for chemical surface refinement
- Final buffing with fine abrasives (P1000–P3000)
4.5 End Forming & Connection Preparation
The terminal ends of the coil tube are machined to precise specifications for integration with FCU headers or manifolds. Options include flat-cut ends for brazed connections or flared ends for mechanical joint assemblies. End preparation is performed using precision cutting and deburring equipment to eliminate burrs and ensure uniform wall thickness at the connection points.
4.6 Quality Assurance & Final Testing
Each completed coil tube assembly undergoes the following verification steps:
- Dimensional Inspection: OD, wall thickness, coil pitch, and overall geometry measured using digital calipers, micrometers, and coordinate measuring machines (CMM)
- Hydrostatic Pressure Testing: All units tested at 2.4 MPa for a minimum 30-minute hold with zero leakage tolerance
- Helium Leak Detection: Optional high-sensitivity leak testing (detection threshold: 1×10⁻⁹ Pa·m³/s) for critical applications
- Visual & Surface Inspection: Full visual examination for surface defects, weld integrity, and finish quality
- Chemical Analysis Verification: Spectroscopic confirmation of alloy composition per batch
5. Applications
5.1 Commercial HVAC Systems
The WA-V-102C3L30 coil tube is the primary heat exchange element in Fan Coil Units deployed across commercial buildings including office complexes, shopping malls, hotels, and hospitals. It facilitates both cooling and heating operations by transferring thermal energy between the circulating fluid (chilled water, hot water, or refrigerant) and the air stream moved by the FCU fan.
5.2 Industrial Process Cooling
In industrial settings, this coil tube configuration is employed in process air handling units, cleanroom HVAC systems, and specialized temperature-controlled environments where corrosion resistance and reliability are paramount.
5.3 Residential & Light Commercial Applications
The compact triple-row coil design provides high surface-area-to-volume ratios, making it suitable for concealed ceiling-mounted and wall-mounted FCU installations in residential apartments, retail spaces, and light commercial premises.
5.4 Specialized Environments
- Food Processing Facilities: Corrosion-resistant construction suitable for food-grade environments
- Pharmaceutical Cleanrooms: Mirror-polished surface minimizes particulate accumulation
- Marine & Coastal Installations: Superior resistance to salt-laden atmospheric conditions
- Chemical Processing Plants: Compatibility with mildly corrosive process fluids
6. Quality Certifications & Standards Compliance
The WA-V-102C3L30 coil tube and its manufacturing processes conform to the following international and national standards:
| Standard / Certification | Scope |
|---|---|
| ISO 9001:2015 | Quality Management System |
| ISO 14001:2015 | Environmental Management System |
| ASTM A269 / A270 | Stainless Steel Tubing Material Specification |
| ASME B31.9 | Pressure Piping — Refrigeration and Air-Conditioning |
| EN 10217-7 | Technical Delivery Conditions for Stainless Steel Tubes |
| GB/T 12771 | Chinese National Standard for Stainless Steel Seamless Tubes |
| ISO 1307 | Dimensional Tolerances for Tubes and Pipes |
| CE Marking | European Conformity for Pressure Equipment Directive (PED 2014/68/EU) |
| SGS / TUV Inspection | Third-Party Quality Verification |
7. Unique Selling Points
- Enhanced Thermal Performance: The mirror-polished interior surface (Ra ≤ 0.4 μm) reduces hydraulic resistance by up to 15% compared to standard finish tubing, improving overall heat transfer coefficient (U-value) and system COP (Coefficient of Performance).
- Triple