Field Controls 46220901 4" RC Barometric Draft Control

The Field Controls 46220901 4" RC Barometric Draft Control is a mechanical airflow regulation component used to maintain consistent draught pressure within fuel-burning systems by balancing chimney or vent stack conditions. It uses a weighted damper mechanism that automatically adjusts to changes in pressure, allowing controlled dilution air to enter when the draught becomes excessive. In HVAC systems it is mounted on flue piping of boilers, furnaces, and water heaters to stabilise combustion conditions and prevent over-drafting. It helps ensure efficient fuel burning, reduces soot formation, and supports safe venting performance under operating conditions.