F88703
525  Rain Repellent System Equipment Location 
May 15/72  Figure 1  30-43-0 
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

3.  Visual Reservoir and Plumbing
A.  The container receptacle is connected by an adapter and fittings, through a shutoff valve to a translucent fiberglass fluid reservoir mounted below the receptacle (Fig. 1). The container, receptacle and reservoir are all supported by a common bracket. The can valve adapter, shutoff valve, and plumbing are enclosed in a plastic cover with cutouts for access to the shutoff valve and for viewing the reservoir. The reservoir contains a red float level indicator, which is visible through the side of the reservoir. A decal on the cover indicates the fluid level at which the container should be replaced. When the level of the fluid is at the container replacement level approximately ten individual repellent applications of fluid are left in the reservoir and plumbing leading to the spray nozzles.
B.  From the reservoir connection, a teflon supply line is routed below the control cabin floor to a stainless steel T-connection mounted forward of the windshield. The T is connected by stainless steel tubing to a solenoid control valve for each window.
4.  Solenoid and Spray Nozzles
A.  The solenoid valves are normally closed electrically operated 28-volt dc valves (Fig. 2). The valves control the flow of repellent fluid released to the spray nozzles and are coupled directly to the nozzles.
B.  The spray nozzles are mounted externally at the base of each No. 1 window inboard of the windshield wiper drive shaft (Fig. 1). Each nozzle has four spray holes which direct the repellent fluid onto the windshield.
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F88781
525  Rain Repellent System Circuit 
May 15/72  Figure 2  30-43-0 
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

5.  Time Delay Module
A.  Each solenoid valve is controlled by an independent electrical control circuit (Fig. 2). The electrical control components of each circuit consist of a system control switch and a time delay circuit. The control switches are pushbutton type momentary switches and are located on the overhead panel. The time delay circuit is mounted within the delay module, which is connected to the solenoid valve electrical connector. A resistor in the time delay circuit is variable and may be adjusted to change the time required to charge a capacitor and thus control the time delay action. The delay is adjusted to open the circuit to the solenoid valve after the required amount of repellent has been sprayed on the window, allowing the valve to close. 
6.  Operation
A.  With the pressurized fluid container installed in the system receptacle, the shutoff valve in the open position, and 28-volt dc power available on the No. 1 and No. 2 dc bus, the system is ready for use. The operation of the rain repellent system for each window is individually controlled by pushing the respective control switch (Fig. 2). Pushing the control switch completes a circuit from its respective RAIN REPELLENT circuit breaker through the switch and time delay circuit, to energize the respective control valve solenoid. Actuation of the solenoid valve allows the pressurized reservoir to supply rain repellent through the tubing to the spray nozzles and onto the window. When the required amount of repellent has been sprayed on the window the time delay circuit will operate to break the circuit, de-energizing the solenoid valve and preventing further flow of repellent solution. Releasing the control switch breaks the circuit to the relay coil, de-energizing the relay and closing the relay points for the next operation. The pressurized fluid container will replenish the fluid in the reservoir as the fluid level drops and the pressure is decreased.
B.  When actuating the control switch, hold switch depressed until fluid stops flowing from the nozzle. Rapid actuations of the control switch (less than 0.2 seconds) may de-energize the solenoid valve before the time delay relay operates, releasing less than the normal amount of fluid.
525 
30-43-0 Page 6  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  May 15/72 

RAIN REPELLENT SYSTEM - TROUBLE SHOOTING
EFFECTIVITY
All airplanes with active rain repellent systems

May 01/99 30-43-0 Page 101
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
　
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