The invention relates to a compressed air supply installation (10, 11, 12, 20, 30) for operating a pneumatic installation (90), especially an air suspension installation of a vehicle, comprising a compressed air supply unit (1), a compressed air port (2) towards the pneumatic installation (90), a venting port (3) towards the surroundings, a first pneumatic connection between the compressed air supply (1) and the compressed air port (2), said pneumatic connection having an air drier (61) and a shut-off valve, and a second pneumatic connection between the compressed air port (2) and the venting port (3). According to the invention, the shut-off valve is designed as a pneumatically pilot-controlled check valve (63, 64).