Carrier 331709-756 TXV Kit

The Carrier 331709-756 TXV Kit is a field-installed R-410A thermal expansion valve designed for precision refrigerant metering in high-efficiency residential heat pumps and air conditioning systems. Engineered for Carrier, Bryant, and Payne fan coils and evaporator coils, this hard shut-off TXV manages superheat under varying thermal loads to prevent liquid slugging and ensure optimal evaporator saturation. The kit utilizes a mechanical flare fitting for simplified installation without brazing, reducing the risk of heat damage to the internal needle and seat assembly. As an OEM refrigerant flow control component, it responds to changes in suction line temperature and pressure to maintain the required pressure drop across the orifice. When performing a cooling system repair, ensuring the external equalizer line and sensing bulb are properly insulated is critical for maintaining the design efficiency of the refrigeration cycle.

Key Technical Benefits

• Precise Superheat Control: Modulates refrigerant flow accurately to maximize heat transfer efficiency in R-410A systems.
• OEM Compatibility: Exact replacement for specified Carrier evaporator coils, ensuring factory-standard performance and pressure ratios.
• Mechanical Connection: Features threaded fittings to streamline the TXV replacement process and eliminate flux contamination risks.
• Durable Construction: Built to withstand high-side discharge pressures and maintain consistent refrigerant metering over extended duty cycles.

Common Installation Questions

Where should the sensing bulb be mounted?
The sensing bulb must be securely strapped to a horizontal section of the suction line at the 12 o'clock or 4 o'clock position (depending on line diameter) to ensure accurate thermal feedback for the thermal expansion valve.

Does this kit require additional fittings?
This 331709-756 kit is designed for direct integration with compatible Carrier flare connections; however, technicians should always inspect the external equalizer port for debris before final assembly.

Is this valve compatible with R-22?
No, this component is calibrated specifically for the pressure-temperature characteristics of R-410A refrigerant and should not be used in legacy HVAC systems.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.