What must happen during recovery to prevent pressure build-up in the system?

• A. Evacuate the system
• B. Leave the system open
• C. Monitor the temperature
• D. Seal all service valves

Answer: (A)

During recovery, it is crucial to evacuate the system to prevent pressure build-up. This process involves removing the refrigerant from the system and making sure that it is stored in a recovery tank or similar container. By evacuating the system, you are effectively managing the pressure levels within it, which is important because refrigeration systems operate under specific pressure conditions. If the pressure were to build up during the recovery process, it could lead to system malfunctions, leaks, or even safety hazards such as ruptures.

Evacuating the system also ensures that moisture and air, which can contaminate the refrigerant and affect the system's efficiency, are removed. This process is in accordance with EPA regulations, which prioritize safety and environmental protection, especially when dealing with refrigerants that can contribute to ozone depletion or global warming.

The other choices do not contribute to pressure management during recovery: leaving the system open would actually allow outside air in, which is counterproductive; monitoring temperature is important but does not directly prevent pressure build-up; and sealing all service valves might hinder proper recovery if there is no appropriate way for the refrigerant to escape.