Core Value
In commercial HVAC systems and industrial make-up air units, achieving uniform thermal distribution across a large duct is a major engineering challenge. Single straight heating rods often leave cold spots, while excessively dense finned coils can cause severe static pressure drops that strain blower motors. The 220V Multiple U Shape Tubular Heater For HVAC Ducts System resolves this by spreading the active heating zone across a continuous, wide-spanning serpentine layout.
By utilizing CNC mandrel bending to create a series of precise U-turns from a single seamless stainless steel tube, this design maximizes the heated length in a single planar cross-section. The passing airflow is heated evenly as it sweeps across the multiple transverse heating segments.
To ensure safe and reliable installation, this heater is engineered with specialized cold zones. Welded mounting stoppers (locating flanges) are positioned near the ends of the element, allowing the active heating grid to be suspended inside the duct while keeping the flexible lead wire connections safely isolated on the exterior ambient side of the duct wall. Powered by a high-density compacted Magnesium Oxide (MgO) core and premium Ni80Cr20 resistance wire, this heater delivers rapid thermal response and decades of reliable service in demanding airstreams.
- ✓ Maximized Planar Heating Area: The continuous multi-U (serpentine) geometry spans wide ducts, ensuring perfectly uniform air heating without thermal cold spots.
- ✓ Low Aerodynamic Drag: The smooth, unfinned bare tubular design provides excellent heat dissipation while minimizing static pressure drop across the HVAC blower.
- ✓ Isolated Cold Zone Wiring: Integrated mounting stoppers guarantee that the flexible electrical leads remain securely outside the high-temperature airstream.
- ✓ Swaged Dielectric Strength: High-tonnage rotary-swaged MgO insulation protects the internal resistance wire from vibration-induced short circuits.
- ✓ Direct OEM Manufacturing: Fully customizable grid widths, U-bend spacing, wattages, and voltages supplied directly by Hongtai Heater Factory.
Technical Specifications & Performance Data
| Parameter | Standard Specification | Customizable Options | Notes |
|---|---|---|---|
| Product Category | Multiple U Shape Tubular Heater | Straight, Finned, or W-Shape Air Heaters | Engineered for wide-area forced convection |
| Geometry | Continuous Multi-U / Serpentine | Custom grid dimensions and bend spacing | Spans the entire cross-section of square/rectangular ducts |
| Operating Voltage | 220V / 230V AC Single Phase | 110V, 380V, 415V, 480V | Perfectly matched to local commercial power grids |
| Tube Diameter (Ø) | Φ8mm, Φ10mm, Φ12mm | Φ6.5mm, Φ14mm, Φ16mm | Heavier tubing available for high-velocity environments |
| Sheath Material | SUS304 Stainless Steel | SUS321, SUS316L, Incoloy 840, Incoloy 800 | Superior oxidation resistance in circulating hot air |
| Mounting Fixture | Welded Locating Stoppers/Washers | Threaded Bushings, Custom Mounting Plates | Fixes the element firmly against the duct wall |
| Terminal Exit | Flexible High-Temp Lead Wires | Threaded Studs (M4/M5), Spade Lugs | Simplifies wiring in tight electrical cabinets |
| Surface Load | 3.0 – 6.0 W/cm² (Forced Air) | Custom watt densities per CFM | Requires minimum airflow velocity to prevent burnout |
Industrial Applications & Solutions
This wide-spanning serpentine tubular heater is the preferred choice for large-scale air heating equipment:
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HVAC & Air Handling Units (AHUs): Installed directly into the ductwork of commercial buildings to provide supplemental winter space heating and make-up air tempering.
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Industrial Drying Rooms & Ovens: Provides wide-area radiant and convective heat for lumber drying kilns, automotive paint curing rooms, and textile drying chambers.
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Agricultural Dehydration: Used in large continuous-flow crop dryers for grain, tobacco, and commercial food dehydration.
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Load Bank Resistor Grids: Safely dissipates large electrical loads generated during the testing of standby diesel generators and battery backups.
HT Heater Advantage: Why Choose Our Serpentine Heaters?
| Feature | HT Heater Serpentine Element | Generic Welded Heaters | Your Operational Advantage |
|---|---|---|---|
| Tube Integrity | Continuous CNC mandrel bending | Multiple short tubes welded together | Eliminates structural weak points and internal wire stress, ensuring a uniform resistance profile. |
| Mounting Safety | Precision-welded locating stoppers | No fixed mounting points | Prevents the element from vibrating loose in high-CFM airstreams, sealing the duct penetration point. |
| Wiring Reliability | Direct-exit flexible insulated lead wires | Rigid threaded studs that easily oxidize | Flexible leads accommodate tight wiring spaces and eliminate the risk of terminal snap-off. |
| Aerodynamic Profile | Precisely spaced, uniform U-bends | Irregularly bent, clustered tubing | Maintains perfectly even airflow distribution without overburdening your expensive HVAC blowers. |
Installation & Handling Guidelines
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Mandatory Forced Airflow: This bare tubular element is engineered for high-wattage air heating. It must strictly be operated alongside an active HVAC blower. Dry-firing in static, unmoving air will cause the sheath to overheat and fail prematurely.
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Mounting Stopper Alignment: When inserting the heater into the ductwork, ensure that both welded locating stoppers press flush against the exterior of the duct wall or mounting plate.
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Isolate the Cold Zone: Ensure the sections of the tube housing the internal electrical connections, as well as the flexible lead wires, remain entirely outside the heated airstream.
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Safety Interlock Systems: Always wire the heater in series with a differential pressure switch or airflow sail switch. If the duct fan fails or a filter severely clogs, the power to the heating elements must be cut immediately.
Customer Success Stories
Case 1:
ommercial HVAC Equipment OEM (USA)
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Application: VAV (Variable Air Volume) terminal box reheat units for large hospital installations.
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Challenge: Existing finned heaters caused excessive static pressure drops, forcing the system to consume 20% more blower motor energy.
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Solution: Transitioned to Hongtai Heater Factory‘s smooth, bare Multiple U Shape Tubular Heaters custom-bent to match the exact interior dimensions of the VAV boxes.
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Results: PRESSURE DROP REDUCED BY 45%. The serpentine geometry maintained perfectly even heat distribution across the duct while allowing the hospital HVAC system to achieve its strict energy efficiency targets.
Case 2:
Automotive Paint Curing Room Builder (Germany)
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Application: Recirculating hot air plenums for a continuous car body paint curing line operating at 180°C.
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Challenge: Standard straight heating rods created cold channels in the airflow, leading to uneven paint curing and costly rework on the vehicle chassis.
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Solution: Deployed banks of HT Heater’s continuous serpentine multi-U heaters, complete with welded stoppers for quick bulkhead mounting and flexible silicone leads for easy electrical cabinet routing.
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Results: 100% UNIFORM AIR TEMPERATURE. The sweeping multi-U design enveloped the entire airstream, completely eliminating cold spots and reducing the paint defect rate to zero.
Pricing & Procurement Options
- OEM Customization: Tailored shapes, custom cutout holes for pipe nozzles, specialized voltage/wattage configurations, and custom strap lengths.
- Lead Times: Custom samples: 3–5 working days. Bulk production orders: 8–12 working days upon technical drawing sign-off.
- Packaging & Shipping: Individually bagged with protective foam padding and packed into heavy-duty 5-ply export cartons to prevent bending or lead wire stress during international transit.
- Minimum Order Quantity (MOQ): Low MOQ starting at 5–10 units for custom dimensions; competitive volume pricing tiers for equipment manufacturers.
Global Certifications & Compliance
- CE Marking
Fully compliant with European safety and environmental standards. - LVD Compliance
Low Voltage Directive tested for continuous thermal load safety. - RoHS Compliant
Constructed using environmentally safe, lead-controlled brass alloys. - ISO 9001
Certified quality control covering CNC machining, coil pressing, and electrical testing.
Quality Documentation: Certificate of Conformity (COC) and insulation resistance test reports included.
Comprehensive After-Sales Support
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- Warranty: 1-Year Comprehensive Warranty covering internal heating element and built-in sensor.
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Technical Support: Application engineers available for wattage distribution calculation, thermocouple calibration, and nozzle fitting assistance.
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Global Response Network: BACKED BY 30+ YEARS MANUFACTURING EXPERIENCE with technical inquiry feedback within 2 hours.
Ready to Optimize Your Injection Molding?
Next Steps:
- 📧 Request Custom Quote – Send your nozzle dimensions, wattage, voltage, and HT-CLW-450 drawing requirements.
- 🔧 Free Design Consultation – Work with our thermal engineers to optimize heat distribution and lead insulation.
- 📦 Order Test Samples – Evaluate thermal performance on your injection molding machine.
- 📞 Contact Hot Runner Experts – Response within 2 hours
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