EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Hard
During evacuation of a low-pressure chiller, if a significant amount of moisture is present in the system, what is the most effective method to remove it?
- APressurize with nitrogen and then re-evacuate.
- BHeat the system while evacuating.
- CInject a desiccant directly into the refrigerant lines.
- DTriple evacuate the system, breaking the vacuum with nitrogen.
Show answer & explanationAnswer & explanation
Correct answer: B. Heat the system while evacuating.
To effectively remove moisture during evacuation, especially in significant amounts, heating the system is crucial. Heat causes the liquid water to vaporize, allowing the vacuum pump to remove it as vapor. This is often combined with pulling a deep vacuum.
Why the other options are wrong
- A. While nitrogen helps sweep contaminants, it's not the most effective for large amounts of moisture without heat.
- C. Injecting desiccants into lines is not a standard or recommended practice for bulk moisture removal during evacuation.
- D. Triple evacuation is good for general contaminants and some moisture, but heating significantly enhances moisture removal.
Moisture Removal During Evacuation
Techniques used to effectively eliminate moisture from refrigeration systems during the evacuation process.
- Moisture must be vaporized to be removed by vacuum pump.
- Heating the system accelerates vaporization.
- Deep vacuum alone may not be sufficient for large amounts.
Memory trick: Heat the system, watch water mist 'em!