Slant Fin 412-705-040 Damper Assembly 30067439-890 Always verify your header material

Always verify your header material and ID dimensions before starting the repair

Verify your original part number or specific furnace model compatibility with a technician before installation

80" WC Calibration: Ensures the boiler only fires when the venting system is operating at the correct efficiency and safety levels

5 Amp DC power supply provides the steady voltage regulation necessary to maintain calibration accuracy across your control loop

Slant Fin 412-705-040 Damper Assembly 30067439-890 Always verify your header materialThe Slant Fin 412 705 040 is a heavy duty 5 inch automatic vent damper assembly engineered specifically for high efficiency hydronic heating systems. Designed as a direct replacement component, this motorized flue damper prevents standby heat loss by sealing the vent pipe when the burner is not firing, significantly improving the AFUE rating of the boiler. This assembly features a robust internal synchronous motor and built in safety interlock