Question 127Refrigeration & AC - QMED

The correct answer is D) liquid recovery using a liquid pump, followed by vapor recovery using a vacuum pump based recovery unit. This is the most cost-effective method to recover refrigerant from a low-pressure chiller with more than 500 lbs of refrigerant and meet EPA requirements. The EPA requires the use of a liquid pump to recover the liquid refrigerant first, followed by a vacuum pump based recovery unit to recover the remaining vapor refrigerant. This two-step process ensures the maximum amount of refrigerant is recovered, which is the most cost-effective approach compared to using only a vapor recovery unit or a liquid pump alone. The other options are incorrect because they do not fully comply with EPA regulations for large refrigerant recovery operations. Option A is less efficient than the required two-step process, while options B and C do not utilize both liquid and vapor recovery methods as required.