Final answer:
Recovery cylinders should not be overfilled to prevent safety risks such as rupture or explosion due to increased pressure, as well as ensuring proper refrigeration system performance and compliance with environmental regulations.
Step-by-step explanation:
Recovery cylinders should never be overfilled because doing so can lead to increased pressure within the cylinder, which poses significant safety risks. As the temperature rises, the pressure inside a cylinder can increase if there isn't enough room for the refrigerant to expand. This can cause the cylinder to rupture or explode, potentially leading to property damage, injuries, or even fatalities.
Furthermore, overfilling recovery cylinders can also affect the performance of refrigeration systems. When the refrigerant is not allowed space to expand, this can lead to incorrect pressure readings and inefficient refrigerant recovery, which compromises the integrity of the system you are working on. In addition, regulations such as the United States Environmental Protection Agency's (EPA) Clean Air Act specifically dictate proper filling levels to prevent accidental release of refrigerant gases into the atmosphere, which are harmful to the environment.
It is crucial to adhere to the manufacturer's specifications regarding the maximum fill capacity, usually around 80% of the cylinder's volume. Using proper equipment, such as scales and gauges, is essential to ensure that cylinders are not overfilled during the recovery process.