A175 Actuator Air Supply Block & Bleed Valves

A175 Pneumatic supply air block and bleed valves are used as a manual override bypass valve between pneumatic actuators and a Namur solenoid valve. Under normal operation, air flows freely into the actuator. In case of maintenance or manual operation via manual override gearbox (A280 Series), the spool is shifted to block pressure ports and exhaust the pressurised air from chambers of actuator for safe manual operation.