A butterfly bypass valve includes a housing defining a bypass flow passage with a pivotable throttle plate therein. An outer edge of the throttle plate in a closed position is in sealing engagement with a sealing portion of the housing such that the throttle plate restricts fluid flow through the bypass flow passage. The throttle plate is pivotable to an open position to allow fluid flow through the bypass flow passage. A port in the housing allows a portion of fluid passing through the bypass flow passage to be removed when the throttle plate is pivoted to the open position. A predetermined amount of pivoting of the throttle plate toward the open position can occur so as to allow flow through the port, while maintaining the edge of the throttle plate in substantially sealing engagement with the sealing portion so as to substantially prevent flow through the bypass passage.