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398E030000 – Liebherr OEM Thermostat Assembly
Available now on the Airparts.aero Marketplace.
The Liebherr 398E030000 is a high-precision, OEM-certified thermostat assembly designed for critical thermal management within aircraft environmental control systems (ECS) and engine cooling circuits. As a primary sensing and regulation component, this thermostat ensures that bleed air temperatures or liquid coolants remain within a strict operational envelope, preventing system over-temp conditions that could lead to component failure or cabin discomfort. Engineered by Liebherr-Aerospace—a global leader in air management systems—the 398E030000 is a linchpin for the reliable operation of modern turbine aircraft.
This assembly utilizes advanced thermostatic actuator technology to modulate flow valves or bypass circuits based on real-time temperature fluctuations. Unlike standard industrial thermostats, the 398E030000 is ruggedized to withstand the extreme vibration, pressure transients, and thermal cycling characteristic of high-altitude flight. Its failure-proof design ensures that in the event of a mechanical anomaly, the system typically defaults to a "fail-safe" position (such as full-open cooling) to protect the airframe and power plant. For procurement specialists and maintenance directors, this Liebherr assembly represents the gold standard in thermal reliability and system integration.
Key Features
Precision Wax-Pellet Actuator: Employs a high-stability thermal expansion element that translates minute temperature changes into powerful mechanical movement for precise valve modulation.
Corrosion-Resistant Housing: Fabricated from high-grade stainless steel or nickel-based alloys to resist oxidation and chemical attack from engine fluids and atmospheric contaminants.
Rapid Response Time: Engineered with high-conductivity materials to ensure near-instantaneous reaction to temperature spikes, protecting downstream sensitive electronics and structures.
Hermetically Sealed Sensing Element: Protects the internal thermal charge from pressure variations at high altitudes, ensuring consistent calibration from sea level to the aircraft's ceiling.
Vibration Dampened Internal Geometry: Optimized to prevent "chatter" and premature wear of the valve seat in high-frequency engine environments.
Technical Specifications
Part Number: 398E030000
Manufacturer: Liebherr-Aerospace
Component Type: Thermal Control Valve / Thermostat Assembly
Operating Temperature Range: (Specify per OEM CMM; typically calibrated for ECS or Engine oil limits)
Material: A-286 CRES or Inconel (dependent on specific application zone)
Medium: Air or Liquid Coolant (Refer to IPC for specific system use)
Maximum Operating Pressure: Designed for high-pressure bleed air or pressurized cooling loops.
Governing Specifications: RTCA DO-160 (Environmental), MIL-STD-810
Certification: EASA Form 1 / FAA-PMA / Liebherr OEM Original Equipment
Aircraft Compatibility
Airbus A320 Family (A318, A319, A320, A321)
Airbus A220 Series
Bombardier CRJ Series
Embraer E-Jets (E170/190)
Note: This assembly is used across various platforms utilizing Liebherr ECS or engine management hardware. Always consult the Illustrated Parts Catalog (IPC) to verify the correct dash-number and system effectivity.
Applications
Environmental Control System (ECS): Regulating the temperature of bleed air before it enters the cabin mixing manifold.
Engine Oil Cooling: Controlling the bypass flow through fuel-oil heat exchangers (FOHE) or air-oil coolers.
Avionics Cooling: Ensuring the liquid or air loops for high-power electronics remain at optimal operating temperatures.
Why Choose 398E030000?
Thermal regulation in a turbine environment is a balance of physics and safety. Choosing the OEM Liebherr 398E030000 ensures that the "crack temperature" (the point at which the valve begins to open) and the "full-flow temperature" are perfectly matched to the aircraft's software logic and heat exchanger capacity. Aftermarket or look-alike thermostats may suffer from "thermal lag" or incorrect spring rates, which can lead to rapid temperature oscillations, damaging heat exchangers and triggering nuisance "Over-Temp" cockpit warnings. By utilizing the 398E030000, operators maintain the engineering margins required for safe, dispatchable flight operations.
The 398E030000 operates on the principle of Thermal Expansion of a Constrained Phase-Change Material. The sensing element contains a specialized petroleum-based wax mixed with copper powder to enhance Thermal Conductivity. As the temperature reaches the predetermined set-point, the wax undergoes a phase transition from solid to liquid, resulting in a significant volumetric expansion. Because the wax is contained in a rigid, hermetically sealed cup, this expansion forces a piston (or "power pin") outward against a calibrated return spring.
This mechanical output is characterized by a high Force-to-Stroke Ratio, allowing the thermostat to overcome the Aero-Dynamic Loading or fluid pressure on the valve face. The use of A-286 CRES for the housing ensures that the component remains Precipitation-Strengthened at elevated temperatures, preventing the warping of the valve seat. Furthermore, the internal spring is manufactured from Inconel X-750 to ensure a constant Modulus of Rigidity across the entire thermal envelope, preventing "calibration drift" over thousands of operational cycles.
Note: The 398E030000 is a critical thermal safety component. Maintenance must involve verification of the "crack" and "full-open" temperatures using a calibrated heat bath as per the Liebherr Component Maintenance Manual (CMM). Any signs of wax leakage or sluggish response are cause for immediate replacement. Installation must be performed by a certified mechanic in accordance with the Aircraft Maintenance Manual (AMM).
Documentation
No public-facing OEM technical data sheet was located for this specific part number. Please refer to the Liebherr-Aerospace CMM or the aircraft-specific AMM for detailed testing and installation data.
