Lennox 79J75 Expansion Valve

The Lennox 79J75 (also identified as 79J7501) is a high-precision thermostatic expansion valve (TXV) designed for consistent refrigerant flow control in Lennox air conditioning and heat pump systems. This HVAC expansion valve features a 3/8" x 1/2" sweat connection, ensuring a leak-resistant, brazed fit for high-pressure R-410A applications. As a critical component in the evaporator coil assembly, the 79J75 modulates refrigerant flow based on heat load to maintain optimal superheat settings, preventing liquid slugging and protecting the compressor. Engineered for reliable metering device replacement, this valve is a direct OEM match for numerous Lennox residential units, providing the precise pressure drop required for efficient heat transfer. When performing a TXV installation, technicians should ensure proper bulb placement and insulation on the suction line to maintain accurate sensing and prevent hunting or erratic system operation during peak demand.

Key Benefits

• OEM Compatibility: Exact replacement for Lennox part numbers 79J75 and 79J7501, ensuring seamless integration with existing liquid lines.
• System Efficiency: Maintains precise refrigerant saturation temperatures to optimize SEER ratings and cooling output.
• Durable Construction: Built to withstand high-pressure fluctuations common in modern R-410A residential split systems.
• Optimized Superheat Control: Prevents compressor damage by ensuring only vaporized refrigerant returns to the suction side.

Common Questions

Is the 79J75 compatible with R-22 systems?
No, this expansion valve is specifically calibrated for R-410A refrigerant pressures and flows; using it with R-22 will cause improper metering and potential system failure.

Does this valve require an external equalizer line?
The Lennox 79J75 is designed as an internally equalized valve or is specific to the evaporator configuration of the matching Lennox coil; always verify your specific coil model for equalizer requirements.

Can I use the 79J75 to replace a fixed orifice piston?
Yes, this TXV can be used to upgrade a fixed orifice system on compatible Lennox coils to improve humidity removal and part-load efficiency.

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.