The Young Regulator 4100-Box is and exhaust air automatic damper that opens and closes by operation of a light switch, motion detector, ect. that is located in the room being exhausted.
Unlike traditional constant volume exhaust systems, the quantity of air being exhausted from the building is dynamic, determined by the number of automatic dampers that are open. The 4100-Box operates only when switched on. When it is not being used, there is minimal air being pulled from that space.
There is no time delay in the 4100-Box operation. If you would like a slow close see the 4000 models.
For relief,a bypass loop or outdoor air can be installed. Optionally a variable speed motor controlled by a pressure sensor can be used.