Question 68Refrigeration & AC - 1st Asst/Chief

The correct answer is B) valves "3", "4", and "6" open; valves "2", "5", "7", "8", and "10" closed. To recover the remaining R-134a refrigerant from the centrifugal chiller as a vapor, the proper valve lineup is to open the compressor suction and discharge isolation valves, as well as valves "3", "4", and "6". This allows the refrigerant vapor to be drawn into the recovery unit's compressor through the suction line, while isolating the refrigerant from the rest of the chiller system by closing valves "2", "5", "7", "8", and "10". The other answer choices are incorrect because they either do not fully isolate the refrigerant from the chiller system or do not provide the appropriate flow path for the refrigerant vapor to be drawn into the recovery unit's compressor.