Most issues stem from venturi burner clogging

Precision Metering: Optimized for R-410A refrigeration cycles to ensure accurate cooling output across varying thermal loads

Durable Construction: High-grade materials prevent blade "flutter" and maintain structural integrity during heavy-duty HVAC operation

or if the system will not engage despite the thermostat calling for it

and moisture ingress

Lennox 97H31 Expansion Valve Els PW 29614 Most issues stem from venturiThe 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