Nitrogen is used to pressurize an R-11 system for non-major repairs as per EPA regulations. A hydraulic press would not operate properly with a gas, such as nitrogen, because gases are compressible and cannot transfer force as effectively as incompressible liquids can.
The student's question pertains to the usage of a gas to pressurize a refrigeration system (R-11) under the Environmental Protection Agency's (EPA) regulations for non-major repairs. According to the regulations, it is allowable to use nitrogen to pressurize an R-11 system for this purpose. Nitrogen is preferred because it is an inert gas that non-reactive, which means it does not react with the system's components nor does it contribute to the depletion of the ozone layer. The choice of nitrogen is crucial for the correct and safe operation during the repair process.
Regarding the 'Check Your Understanding' quiz, a hydraulic press would not operate properly with a gas because hydraulic systems are designed to work with liquids due to their incompressibility. Gases, unlike liquids, are compressible which can cause the press to lose its ability to generate the substantial force needed for its operations. Thus, hydraulic presses require liquids to function effectively.