lubricating oil. The major components of the cart are labeled in figure 3-18. The Freon storage bottle has a capacity of 25 pounds of Freon. The bottle is restrained in the cart by quick-release restraining straps, which permit rapid removal and replacement of depleted bottles. The electric motor-driven vacuum pump is used to evacuate a refrigerant system prior to recharging it with Freon. Evacuating or pulling a vacuum on the system for a short period of time causes any moisture in the system to be vaporized and withdrawn from the system. Moisture in the system, if of sufficient quantity, can freeze at the expansion valve, thus allowing no Freon into the evaporator and cooling would stop. The vacuum pump has a displacement of 3 cubic feet per minute (cfm) and is rated for continuous duty. The heater tank has a capacity of 360 cubic inches and an operating pressure rating of 200 psi at 125°F (52°C). A liquid level sight gauge, mounted vertically on the heater tank, indicates the level of liquid Freon in the tank. A scale, graduated in pounds and ounces, is mounted alongside the sight gauge and ranges from 0 to 17 pounds. The tank is also equipped with a compound pressure gauge, which is graduated from 0 to 30 inches Hg (mercury vacuum) and 0 to 300 psi pressure. A heating blanket surrounds the heater tank and is used to heat the refrigerant for building up tank pressure sufficient for charging a system. The oil charging cylinder stores Ansul 150 lubricating oil used to replenish the vapor cycle compressor oil supply. The cylinder has a capacity of 68 cubic inches and an operating pressure of 100 psi at 125°F. The cylinder is equipped with an oil level sight gauge and an oil charging pressure gauge. A scale, graduated in centimeters, is mounted beside the sight gauge and ranges from 0 to 800 cc. The flexible evacuation and charging hoses are both 180 inches long to accommodate hooking the cart to the unit being evacuated or charged without removing the unit from the aircraft. An aircraft power cable connects primary electrical power from the cart to the aircraft. A deck edge power cable or power cable from electric generating equipment provides power to the cart. Safety Precautions To prevent injury to personnel and damage to equipment, you must observe the following safety precautions and handling procedures when working with Freon gas: 1. Protective equipment (apron, gloves, goggles, and face mask) must be worn. 2. If liquid Freon comes in contact with the skin, treat the skin for frostbite. 3. If liquid Freon comes in contact with the eyes, medical attention must be sought immediately. The following first aid treatment should be administered: Do not rub or irritate the eyes; drop sterile mineral oil into the eyes; then wash the eyes with a boric acid solution if the irritation continues. 4. Freon is stored in cylinders that are color- coded orange with appropriate lettering for identification. These cylinders should be handled carefully because the pressure inside the cylinder depends upon the ambient temperature. Refrig- erant cylinders should not be exposed to high temperatures or flames. Cylinders that are used for high-pressure liquids should never be thrown around, dropped, or used for anything other than their intended purpose. Refrigerant cylinders should never be filled to more than 85 percent of their capacity. 5. Freon tends to dissolve natural rubber; therefore, only the recommended gaskets, O-rings, and packings should be used in the vapor cycle system. SH-60B HELICOPTER ENVIRONMENTAL CONTROL SYSTEMS (ECS) Learning Objective: Identify components and conditions of the ECS for the cockpit, cabin area, and the nose avionics compart- ment of the SH-60B helicopter. The SH-60B helicopter cabin cockpit and nose bay environments are controlled by the ECS, which provides both heating and air conditioning in a range of 2°C to 71°C. Supplementary or backup air circulation is provided at all crew stations by manually controlled air inlets for out- side air. The ECS (fig. 3-19) consists of an air-cycle machine (ACM) (fan, turbine, and compressor), bleed-air ducting, necessary controls and valves, water separator, distribution system, air inlet, and heat-exchanger exhaust duct. The bleed-ai_r portion of the ECS functions from two sources 3-28