Vaillant Thermostatic Expansion Valve 0020175864

The thermostatic expansion valve is a refrigerant metering component used in Vaillant Arotherm and Aurostor heat pump systems. It regulates refrigerant flow into the evaporator, maintaining the correct superheat across the circuit. This version is rated at 8kW.

• Reduced heating or hot water output despite the compressor running normally
• Frost or excessive ice forming on the evaporator or suction line
• Refrigerant circuit pressures outside the expected range for the operating conditions
• Hunting or unstable superheat readings that cannot be corrected by adjustment
• Visible oil staining, corrosion or mechanical damage around the valve body

• Confirm the appliance model and variant against the fitment list above
• Check the existing valve's part number or rating marking where accessible
• Verify the fault has been traced to the expansion valve rather than another circuit component
• Confirm refrigerant type and system charge requirements before starting work