Draft Controls

Draft control is recommended when chimneys or gas vents generate natural draft in excess of the appliance manufacturer’s draft requirements. There are two types of draft control:

– Over draft control dampers
– Barometric dampers

For your specific project, please contact our design team to discuss.

Over draft control dampers, a.k.a. modulating dampers, consist of a controller, pressure transducer, high speed actuator and multi-blade damper. A modulating damper system is specified to manage and maintain a constant draft for single or multiple boilers, water heaters, and other Category I, II, III or IV heating appliances. The multi-blade damper-actuator may be used with any type of chimney or gas vent, including special gas vents, and may be placed in the common manifold or in individual appliance connectors to comply with the NYC’s Department of Environmental Protection. The use of a modulating damper can reduce fuel consumption by 10% or more when installed in individual appliance connectors.

A barometric damper is a device designed to offload natural draft by introducing dilution air into the chimney or gas vent. Typically placed perpendicular to flow in each appliance’s connector, a barometric damper can offload up to 0.3″W.C. before the excessive natural draft acts upon the appliance. Barometric dampers are typically used with Category I or II appliances and other non-condensing appliances where the chimney is designed to operate naturally. Barometric dampers shall be equipped with thermal safety (spill) switches.