The NTI Boiler 64980345 Venturi TFT 340 NRV 148 is an OEM combustion component designed for NTI TFT340 and compatible 340/399 boiler applications. It works by regulating and mixing incoming gas and combustion air, creating the proper air-fuel ratio before the mixture reaches the burner. This supports stable ignition, efficient combustion, and consistent boiler operation. Used in high-... https://www.partshnc.com/nti-boiler-64980345-venturi-tft-340-nrv-148