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DEHYDRATION <br />Proper dehydration procedures through evacuation are important to follow. <br />As every technician knows, the reason for dehydrating a refrigeration system is to remove water and water vapor. If <br />moisture is allowed to remain in an operating refrigeration system, hydrochloric and hydrofluoric acids may form. <br />Evacuation of a system is the suggested method of dehydration. It is not possible to over evacuate a system. <br />Never evacuate a system to the ambient air without first following proper recovery procedures and attaining the mandated <br />vacuum level. <br />The factors affecting the speed and efficiency of evacuation are; size of equipment being evacuated, ambient temperature, <br />amount of moisture in the system, the size of the vacuum pump and suction line. In addition, vacuum lines should be <br />equal to or larger than the pump intake connection. The piping connection to the pump should be as short a length as <br />possible and as large in diameter as possible. The system vacuum gauge should be connected as far as possible from the <br />vacuum pump. Measuring a systems vacuum should be done with the system isolated and the vacuum pump turned off. A <br />system that will not hold a vacuum probably has a leak. During evacuation you may wish to heat the refrigeration system <br />to decrease dehydration time. Dehydration is complete when the vacuum gauge shows that you have reached and held the <br />required finished vacuum. (See water vaporization chart in back of manual.) <br />RECOVERY CYLINDERS <br />Recovery cylinders differ in many ways from disposable cylinders. Disposable cylinders are used only with virgin <br />refrigerant and may NEVER be used for recovery. . <br />Recovery cylinders are specifically designed to be refilled. Recovery cylinders have 2 ports, one liquid and one vapor. <br />Care must be taken not to overfill or heat these cylinders, thereby causing an explosion. The EPA requires that a refillable <br />refrigerant cylinder MUST NOT BE FILLED ABOVE 80% of its capacity by weight, and that the safe filling level can be <br />controlled by either mechanical float devices, electronic shut off devices (thermistors), or weight. Refillable cylinders <br />must be hydrostatically tested and date stamped every 5 years. <br />Refillable cylinders used for transporting recovered pressurized refrigerant must be DOT (Department of Transportation) <br />approved. Approved refrigerant recovery cylinders can easily be identified by their colors, YELLOW TOPS AND GRAY <br />BODIES. All refrigerant recovery cylinders should be inspected for RUST. If they show signs of rust or appear to not be <br />secure they should be reduced to 0 psig and discarded. <br />Mello <br />RECEIVE. <br />MAy 1 a z�,5 <br />ENVIRONM�NTA� <br />NFA`• <br />ray Bode <br />