Lennox 59W21 TXV

The Lennox 59W21 Thermal Expansion Valve (TXV) is a critical 8-ton metering device engineered for precision refrigerant control in high-capacity commercial HVAC systems. Designed with 3/8" x 1/2" ODF sweat connections, this valve ensures accurate superheat maintenance across varying load conditions, preventing liquid floodback and protecting the compressor. The 59W21 features a 30-inch capillary tube and is officially rated as the direct replacement for S1-025-22735-701, making it a drop-in solution for many Lennox, Armstrong, and Ducane air handlers and rooftop units.

When performing a TXV replacement, technicians should note that the Lennox 59W21 is specifically calibrated for R410A refrigerant applications. Utilizing a high-performance expansion valve is essential for restoring system SEER ratings and ensuring balanced evaporator feed. As a veteran-grade HVAC replacement part, this thermal expansion valve features a durable brass body and factory-calibrated power head to provide reliable refrigerant flow regulation in demanding environments. Always replace the liquid line filter drier when opening the system to ensure moisture-free operation.

• Direct OEM Compatibility: Serves as the precise direct replacement for S1-025-22735-701 and 100679-35.
• 8-Ton Cooling Capacity: Specifically sized for large-tonnage commercial air conditioning repair.
• Precision Superheat Control: Maintains optimal evaporator efficiency to maximize HVAC system performance.
• Standard ODF Connections: Features 3/8" x 1/2" sweat ports for streamlined HVAC installation and brazing.
• Extended Capillary Reach: The 30-inch lead provides flexibility for various sensing bulb placements on the suction line.

Is the Lennox 59W21 compatible with R-22 systems?
This specific model is engineered and factory-calibrated for R410A refrigerant. Using it in R-22 systems may result in improper superheat and potential compressor damage.

What are the symptoms of a failing 8-ton TXV?
Technicians typically observe high superheat, low suction pressure, and normal or high subcooling, which indicates a restricted metering device rather than a low refrigerant charge.

Does this valve include the sensing bulb mounting hardware?
Standard Lennox thermal expansion valves include the sensing bulb and capillary; however, the copper sensing bulb must be properly insulated and strapped to the suction line for accurate sensing.

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.