This specific assembly is designed for 124/125 series and older non-FVIR or specific legacy models

For applications requiring a variable differential

This is a uni-directional drier

System Reliability: Helps prevent pressure switch errors and ignition failures by maintaining stable airflow

Lennox 31L98 Flue Transition 326058-758 This specific assembly is designedThe Lennox 31L98 Flue Transition is a critical OEM component designed to provide a secure, airtight connection between the furnace exhaust outlet and the multi stage venting system. Engineered for high efficiency gas furnaces and oil fired boilers, this HVAC vent pipe adapter prevents the escape of toxic combustion gases like carbon monoxide by ensuring a precision fit at the draft inducer or heat exchanger interface. As a genuine Lennox replacement