DISTRIBUTOR VALVES

or tubes of the deice boots (fig. 1-7) are inflated and deflated alternately by applying pressure and suction, causing a wavelike motion that cracks the formed ice and allows it to be carried away by the airstream. The E-2A deice boot system shown in figure 1-8 is pneumatically operated and electrically controlled. Engine bleed air provides the necessary air pressure. The bleed air is regulated by the pressure regulator and relief valve. Suction is provided by the ejector and regulated by the suction relief valve. Suction and pressure gages provide a means of monitoring system readings that indicate proper or improper system operation. The deice system consists of the follow- ing main components: electronic timer, three distributor valves, pressure regulator and relief valve, ejector, suction relief valve, the de- ice boot sections, and pressure and suction gages. ELECTRONIC TIMER.— A timer controls the inflation and deflation of the deice boots by alternately energizing and de-energizing the solenoids of the distributor valves in a specific sequence. Pressure and suction are applied to the boots in the following sequence: the inboard wing boots, the outboard wing boots, the outboard stabilizer and vertical fin boots, and the inboard stabilizer and fin boots. Each group of boots is inflated for approx- imately 5 seconds, and the succeeding group begins inflating approximately 10 seconds after the first group begins deflating. The total time for the complete inflation cycle to all four boot groups is approximately 1 minute. The timer is a sealed unit and is maintained by personnel in the AE rating. DISTRIBUTOR VALVES.— Each of the deice system’s three distributor valves (fig. 1-8) has a pressure inlet port, a suction inlet port, two outlet ports to the deice boots, and an exhaust port. The exhaust port routes air returning to the distribution valve in the deflation cycle overboard to a low-pressure area. The low-pressure exhaust area creates a slight suction to assist in deflation of the boot. The pressure inlet port is connected to the engine bleed-air manifold pressure line. The Figure 1-7.—Deice boot location/operation. suction port is connected to the main suction line from the ejector. Approximately 4 in Hg. suction is available at all times to the distributor valves. Each distributor valve has two solenoids that, when energized, allow air pressure to inflate their respective boot tubes, as was shown in figure 1-7. When the solenoids are de-energized, the valves allow suction to be applied to the boots, holding them down (deflated) in flight. 1-8