A valve having a valve member, which cooperates with a valve seat formed in a housing part in order to control a connection, and the valve seat has an at least approximately conical seat face, which is located at a transition of the connection from a portion of small diameter to a portion of large diameter. The seat face is adjoined, on its side oriented toward the portion of large diameter, by at least one face which is more markedly inclined relative to the longitudinal axis of the connection than the seat face, and on its side oriented toward the portion of small diameter, the seat face is adjoined by at least one face which is less markedly inclined relative to the longitudinal axis of the connection than the seat face.