A valving arrangement for use with or for a blower-based ventilator system, such as a pressure support ventilator, and a pressure support ventilator having such a valving arrangement, in which blower output can be controlled in such a manner that desired levels of pressure are able to be provided without excessive waste of blower output flow. In one preferred embodiment, a first valve is provided that serves to restrict blower flow, without venting the same from the system, along with a second valve for relieving pressure as needed. Also contemplated herein are methods for controlling such a valving arrangement.