Vacuum pump oil should be changed frequently to guarantee optimum performance.
Clean oil is important for peak vacuum pump performance. When the oil becomes contaminated, it reduces the pump's ability to remove moisture from an A/C system, exposing it to potential corrosion. Most A/C RRR machines, like the Robinair 34788, will notify users when to change vacuum pump oil. To make sure the vacuum pump in your A/C RRR machine is performing at an optimal level, users should change the pump oil frequently and especially in the following conditions:
Evacuation of an A/C system that is suspected to be overly moisture laden.
Evacuation of a system where the compressor had failed.
Pump oil looks cloudy or milky.
Vacuum pump has run for 10 hours or more.
Frequent oil changes will help ensure the vacuum pump is always performing at an optimal level, ensuring total moisture removal from A/C systems and proper service.
Information provided by: Robinair, Service Solutions LLC