Zhejiang Gongzheng Machinery Co., Ltd. is a professional manufacturer and supplier of European Unloader Valves, a critical component in the air brake systems of European commercial vehicles. Our unloader valves are designed to precisely control the air compressor's output, ensuring the system operates within the optimal pressure range. We supply a comprehensive range of unloader valves for trucks, buses, and trailers, supporting both OE and aftermarket applications. With a 30,000 m² factory and in-house R&D, we deliver reliable, durable, and high-performance valves that meet the rigorous demands of the global commercial vehicle industry.
We offer a wide selection of unloader valves, each engineered for specific system pressures, port configurations, and integration requirements. Our product line includes standard automatic unloader valves, high-pressure variants, models with integrated tire inflation ports, and dual-circuit inductive versions. Below is a summary of our key models and their typical applications.
| Model / Type | Key Features | Typical Application |
|---|---|---|
| Standard Automatic Unloader Valve | 8.1 bar cut-out, compact design, direct replacement | General truck and trailer air systems |
| High-Pressure System Unloader Valve | 9.5 bar cut-out, reinforced diaphragm, safety valve | Heavy-duty trucks, high-demand pneumatic systems |
| Unloader Valve with Tire Inflation Port | Integrated inflation port, 8.1 bar, corrosion-resistant | Fleet vehicles requiring on-board tire inflation |
| Dual-Circuit Inductive Unloader Valve | Inductive sensor, dual-circuit control, 10 bar max | Advanced EBS/ABS integrated systems |
| Multi-Port Balanced Unloader Valve | Multiple ports, balanced piston, 8.1 bar | Complex pneumatic circuits with multiple consumers |
| Compact 10 Bar High-Pressure Unloader Valve | 10 bar cut-out, compact body, lightweight | Space-constrained installations, high-pressure systems |
Our European Unloader Valves are designed for direct fitment on European commercial vehicles, including MAN, DAF, Iveco, Scania, and Volvo trucks, as well as trailers and buses. Each valve is engineered to match the original equipment specifications for pressure settings, port sizes, and electrical connections (where applicable). We use high-grade materials such as corrosion-resistant aluminum alloys and stainless steel components to ensure long service life in harsh operating environments.
The engineering value we provide includes:
When selecting an unloader valve, the following parameters are critical:
Our valves undergo 100% functional testing before shipment, including pressure calibration and leak testing.
We offer several configuration options to match your specific system requirements:
For automation integration, our inductive unloader valves provide a digital signal that can be used by the vehicle's EBS or telematics system to monitor compressor cycling and system pressure. This enables predictive maintenance and improved fleet management.
Our manufacturing facility is IATF 16949 certified, and our unloader valves comply with ECE R13 and other relevant international standards. Each production batch is subject to:
Installation is straightforward: the valve is mounted directly to the air compressor or inline in the discharge line. We provide detailed installation instructions and torque specifications. Maintenance typically involves periodic inspection of the diaphragm and seals; replacement kits are available. Our technical support team can assist with troubleshooting and system optimization.
To prepare a precise quotation and configuration, we need the following project information:
With this information, we can recommend the most suitable model from our range or develop a custom solution.
The unloader valve controls the air compressor's output by unloading the compressor when the system reaches the cut-out pressure, preventing over-pressurization. It also allows the compressor to run unloaded until the pressure drops to the cut-in point.
Most European trucks use 8.1 bar (120 psi) or 9.5 bar (140 psi) systems. Check your vehicle's service manual or the existing valve's marking. We can also help you determine the correct setting based on your compressor and system components.
Yes, we offer several models with an integrated tire inflation port. These are ideal for fleet vehicles that require on-board tire inflation capability. The port is typically a quick-connect type.
Yes, our valves are designed as direct replacements for OEM unloader valves used on European commercial vehicles. We match the original port sizes, pressure settings, and electrical connections to ensure plug-and-play installation.
For standard models, we maintain inventory and can ship within 7–15 days. Custom configurations (e.g., special pressure settings or port modifications) typically require 3–4 weeks, depending on the complexity and volume.
Yes, we provide product datasheets, installation manuals, and CAD drawings upon request. Our engineering team is available for technical support via email or phone.
For more information or to request a quotation, please contact our European Unloader Valve manufacturer team. You can also explore our full range of European Commercial Vehicles components.
Our portfolio also includes Products, European Air Dryer for applications with different operating ranges, interfaces or integration requirements.