Stainless Steel Coil Tube for Fan Coil Units — Model JX-CT Series
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd. | Product Code: 1607
1. Product Overview
The JX-CT Series Stainless Steel Coil Tube is a precision-engineered coiled heat exchanger tube specifically designed for use in Fan Coil Unit (FCU) assemblies within commercial and industrial HVAC (Heating, Ventilation, and Air Conditioning) systems. The coil tube serves as the primary heat transfer medium, enabling efficient thermal exchange between the refrigerant or hot water circuit and the ambient air stream drawn through the fan coil unit.
Based on extensive engineering analysis of common design challenges in fan coil unit systems — including uneven airflow distribution, condensate drainage issues, corrosion resistance demands, and thermal efficiency optimization — Wenzhou Jixing Metal Materials Co., Ltd. has developed this coil tube product to address these critical performance bottlenecks. The product is engineered to deliver superior thermal conductivity, exceptional corrosion resistance, and long-term structural integrity under demanding operating conditions.
2. Material & Properties
The JX-CT Series coil tube is manufactured from high-grade austenitic stainless steel, selected for its outstanding combination of mechanical strength, corrosion resistance, and thermal performance.
- Primary Material Grades: SUS304 (ASTM A269 TP304), SUS316 (ASTM A269 TP316), and SUS321 (ASTM A269 TP321)
- Corrosion Resistance: Exceptional resistance to pitting corrosion, crevice corrosion, and stress corrosion cracking (SCC), particularly in humid or chemically aggressive environments
- Thermal Conductivity: 14.9–16.3 W/(m·K) at 20°C, ensuring efficient heat transfer across the tube wall
- Operating Temperature Range: −196°C to +870°C (SUS304); −196°C to +925°C (SUS321)
- Surface Treatment: Electropolished or passivated finish (Ra ≤ 0.4 μm) to minimize fouling and enhance heat transfer coefficients
- Hygienic Compliance: Meets FDA and 3-A sanitary standards for food-grade and pharmaceutical applications
3. Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | 6.35 mm, 9.52 mm, 12.70 mm, 15.88 mm (1/4", 3/8", 1/2", 5/8") | ASTM A269 / ASME B36.19M |
| Wall Thickness | 0.5 mm – 1.5 mm (customizable) | ASTM A269 / EN 10217-7 |
| Coil Diameter (Bundled) | 150 mm – 600 mm (configurable per FCU design) | Manufacturer Specification |
| Tube Length (Uncoiled) | 10 m – 50 m per continuous coil | Custom Order |
| Bend Radius | ≥ 3D (minimum bending radius = 3 × OD) | ISO 4427 |
| Pressure Rating | Up to 1.6 MPa (232 psi) at 25°C | EN 10217-7 / PED 2014/68/EU |
| Heat Transfer Efficiency | U-value ≥ 550 W/(m²·K) (water-to-air) | ASHRAE Standard 15 |
| Surface Roughness | Ra ≤ 0.4 μm (electropolished); Ra ≤ 0.8 μm (standard) | ASTM B475 |
| Coil Pitch | 1.5D – 2.5D (optimized for airflow uniformity) | ASHRAE Handbook — HVAC Systems |
| Maximum Operating Pressure | 4.0 MPa (hydraulic test at 1.5× working pressure) | EN 10217-7 / GB/T 14976 |
| Material Certification | EN 10204 Type 3.1 mill certificate per heat number | ISO 9001:2015 |
4. Manufacturing Process
The JX-CT Series coil tube undergoes a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and consistent performance:
- Raw Material Procurement: Only certified stainless steel seamless tubes from approved mills (e.g., Outokumpu, Sandvik, POSCO) are sourced, with full traceability to heat numbers.
- Dimensional Inspection & Cut-to-Length: Incoming tubes are inspected for OD, wall thickness, and straightness using laser measurement systems. Tubes are cut to specified lengths with burr-free finishing.
- End Preparation & Threading: Tube ends are beveled, deburred, and threaded (where required) to ensure leak-free connections with headers and manifolds.
- Coiling Operation: Tubes are cold-coiled using precision hydraulic coiling machines with controlled bend radii (≥ 3D) to prevent wall thinning, ovality deformation, or stress-induced cracking. The coiling process is monitored in real-time for dimensional conformance.
- Welding & Brazing (if applicable): Where coil tubes are welded to headers or manifolds, TIG (Tungsten Inert Gas) welding is performed under argon shielding to maintain interior cleanliness and prevent oxidation.
- Surface Treatment: Electropolishing or chemical passivation is applied to achieve the specified surface finish, enhancing both corrosion resistance and heat transfer performance.
- Hydrostatic Pressure Testing: Each coil tube assembly undergoes 100% hydrostatic testing at 1.5× the maximum operating pressure for a minimum of 60 seconds to verify pressure integrity and absence of leaks.
- Final Quality Inspection: Dimensional verification, visual inspection, and material certification documentation are completed prior to packaging and shipment.
5. Applications
The JX-CT Series Stainless Steel Coil Tube is purpose-built for the following applications:
- Commercial HVAC Systems: Primary heat exchanger coil tubes in fan coil units for office buildings, hotels, hospitals, and retail spaces
- Industrial Process Cooling: Chilled water coil tubes in process air handlers and industrial dehumidification systems
- Pharmaceutical & Food Processing: Hygienic-grade coil tubes in cleanroom HVAC systems where stainless steel construction is mandated
- Marine & Coastal Environments: SUS316-grade coil tubes for fan coil units operating in high-salinity or high-humidity environments
- Data Center Cooling: Precision air handling units requiring high-efficiency heat exchange with minimal maintenance
- Residential HVAC: Premium residential fan coil units and mini-split systems requiring long service life and corrosion resistance
6. Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications:
- ISO 9001:2015 — Quality Management System certification
- EN 10204 Type 3.1 — Material test certificates for all production batches
- CE Marking — Compliance with EU Pressure Equipment Directive (PED 2014/68/EU) for pressure-bearing components
- ASME Stamp — Compliance with ASME B31.5 for refrigeration piping (where applicable)
- GB/T 14976 — Chinese national standard for seamless stainless steel tubes
- RoHS & REACH Compliance — Restricted Substances compliance for global market access
- Third-Party Testing — Products verified by SGS, TÜV, or Bureau Veritas upon customer request
7. Unique Selling Points
The JX-CT Series addresses several well-documented design challenges in fan coil unit engineering, as identified in industry literature on FCU design optimization:
- Enhanced Condensate Management: The electropolished interior surface (Ra ≤ 0.4 μm) minimizes water film adhesion, reducing condensate carryover and improving dehumidification efficiency — a critical issue in FCU design.
- Superior Corrosion Resistance: SUS316-grade option with 2–3% molybdenum content provides exceptional resistance to chloride-induced pitting, extending service life in coastal and industrial environments beyond standard carbon steel or copper alternatives.
- Optimized Coil Geometry: Coil pitch and bend radius are engineered to ensure uniform airflow distribution across the heat exchanger face, addressing the common issue of airflow maldistribution that degrades FCU performance.
- Full Traceability: Every coil tube is traceable to its original steel mill heat number, ensuring complete supply chain accountability and material provenance verification.
- Customizable Configurations: Flexible OD, wall thickness, coil diameter, and surface finish options allow OEMs to tailor the coil tube to specific FCU design requirements and thermal load calculations.
- Long Service Life: With proper installation and maintenance, the JX-CT Series coil tube offers a design life exceeding 25 years, significantly reducing lifecycle costs compared to copper or aluminum alternatives in corrosive environments.
Wenzhou Jixing Metal Materials Co., Ltd. is committed to delivering precision-engineered stainless steel coil tube solutions that meet the most demanding specifications in the HVAC industry. For technical inquiries, custom specifications, or bulk order quotations, please contact the engineering department directly.