Lennox 97H31 Expansion Valve

The Lennox 97H31 Expansion Valve is a 3-ton, R-410A compatible thermostatic expansion valve (TXV) engineered for precision refrigerant metering in high-efficiency cooling systems. This HVAC expansion valve replacement is essential for maintaining the correct superheat and ensuring the evaporator coil operates at peak thermal efficiency. Designed for compatibility with various Lennox residential air handlers and heat pump evaporators, the 97H31 TXV features a robust balanced-port design that compensates for varying pressure drops across the valve, providing stable liquid flow control even during fluctuating load conditions. For technicians performing Lennox AC repair, this component ensures consistent system pressures and prevents liquid slugging, which protects the compressor from premature failure. Utilizing a high-grade capillary tube and sensing bulb, the valve responds rapidly to temperature changes at the suction line exit, making it a reliable solution for maintaining R-410A refrigerant flow control in demanding climate applications.

Technical Specifications & Benefits

• Precise Superheat Control: Automatically adjusts refrigerant flow to maintain optimal evaporator performance and system efficiency.
• R-410A Optimized: Specifically calibrated for high-pressure refrigerant metering devices used in modern HVAC systems.
• Durable Construction: Built to withstand the thermal stresses of frequent cycling in both cooling and heat pump modes.
• 3-Ton Capacity: Sized precisely for 36,000 BTU systems to ensure accurate load matching and prevent system hunting.

Common Installation Questions

How do I know if my Lennox 97H31 TXV has failed?
Common indicators of a failing Lennox 97H31 include abnormal suction pressures, evaporator coil icing, or the compressor tripping on high-pressure limits due to restricted refrigerant flow.

Is this expansion valve compatible with older R-22 systems?
No, this valve is factory-calibrated for R-410A systems. Using it with R-22 will result in incorrect superheat settings and potential equipment damage.

Should the sensing bulb be insulated after installation?
Yes, for the 97H31 to sense suction line temperature accurately, the bulb must be securely clamped at the 10 or 2 o'clock position and wrapped with foam insulation to prevent interference from ambient air.

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.