Two sensors are located in the cooling loop. The sensors are isolated from the coolant by being installed in wells that are filled with thermal grease. Both sensors are identical in construction, but each has a different purpose in the system. One sensor is mounted in the missile return line. The other sensor is in the missile supply line of the missile loop. Each sensor contains two sensing elements. One element

Figure 1-19.- Liquid coolant service unit.

performs the primary sensing function, and the other is used for the built-in test (BIT). Fairing Interlock Switch The fairing interlock switch provides an electrical connection for the missile coolant pump motor and pressure switch circuits. The switch is closed when the right Phoenix fairing is installed.

Liquid Cooling Control Panel

The liquid cooling control panel is located on the NFO's left side console. When the liquid cool-ing switch is set to the AWG-9/ AIM-54 position, it activates both the radar and missile cooling loops of the system.