US Patent 9372009 Pressure control with coarse and fine adjustment

A pressurization control system configured to regulate air pressure within a space includes a first damper fluidly coupled to an air supply, the first damper configured to control delivery of an air flow, and a second damper having an operating range, the second damper fluidly coupled to the air supply and the first damper, the second damper configured to supplement delivery of the air flow. The pressurization control system further includes a room controller configured to provide a control signal to the first and second dampers, wherein the control signal drives the first damper to direct the air flow towards the operating range, and wherein the control signal drives the second damper to direct the air flow towards a set point.