Engine 2014: Electricity

1. A prevents contamination of the recovery unit compressor's lubricating oil with the disabled unit compressor's lubricating oil
2. B prevents slugging of the recovery unit's compressor with liquid refrigerant
3. C allows separation of oil from the recovered refrigerant so that an equal amount of new oil may be recharged when the unit is recharged with refrigerant
4. D all the above

Tip: press A-D to answer