Abstract: A pressure control system for controlling pressure in a fluid system includes a compressor for producing pressurized fluid coupled to a rotor valve, a pressure controller, and a visual low-pressure indicator. A manifold directly supports the valve and has, integrated within, the pressure controller, the low-pressure indicator, and the output connections. The pressure controller includes a plunger and a spring communicating with the fluid system. The pressurized fluid acts against the plunger and the spring, and excess fluid is discharged when pressure exceeds a predetermined value. The low-pressure indicator includes a diaphragm movable away from a transparent window, providing a visual indication of the pressure within the system. The manifold assembly provides connectors for supplying fluid to the system.