In an electrical multi-purpose valve for supplying secondary air into an exhaust system of an internal combustion engine, in which a power-actuated closing member controls a valve orifice in a passage between an inlet from an air supply line and an outlet to the exhaust system, a non-return valve is arranged downstream of the closing body in the direction of the flow of the air through the valve between the non-return valve and the valve outlet, and baffle devices are provided which deflect exhaust gas entering the valve from the outlet at least once by an angle of about 90°. All Multi-Purpose Valves feature the exclusive Heyer-Schulte® On-Off device. This integral on-off control can be utilized to monitor for shunt dependency, can assist in controlling ventricle decompression and allows easy proximal flushing and patency testing. It is used in the treatment of hydrocephalic patients to shunt cerebrospinal fluid (CSF) from the lateral ventricles of the brain into either the right atrium of the heart or the peritoneum.