vacuum pump oil in gage set lines
 

after evacuating a mini split system the gauge set lines seemed to be full of vacuum pump oil. On a r-410 system is this something that would be a system killer or just reduce the system efficiency a little if some vacuum pump oil got in the AC system? The pump has a check valve and to my knowledge was not unplugged. The electronic vacuum gauge was showing 140 microns when I closed things off. I did not notice the oil until I had opened the valves on the unit so I can not "check" the lines to see if there is oil. Choices are recover the charge, clean and start over or run it. I do not have the recovery tools or access to refrigerant so not an easy thing to be cautious. The system might be dry or it might have several ounces of vacuum pump oil in the lines.

If you had a vacuum in the lines and then opened the service valves the large pressure of the freon inside the condensor would fill your hoses and pressurize them and the oil in them. The only way it should/could get in the system is if you added some more freon to the lines as the flow would be into the system. Nothing you can do about it now as it may mix with the compressor oil. If it is too thick the capillary lines will plug and it won't cool properly so you should notice that.

did you lose the oil level in the pump itself :wink:if not it's no big deal

The gauge set has a valve on the end, it was closed when I opened the service ports.

The lines were full of oil. The pump level was down a little but still within the operational range.

You should be okay then. Apparently you are not supposed to go below 500 microns on an open system or it can damage the compressor. I watch the microns carefully and shut down the valves as soon as it drops below 500 on a closed or open system. Apparently the oil starts to flash into vapor or some such a thing. Maybe Beenthere or one of the other guys has heard of this too ???

The vacuum was just on the lineset. So are you saying a little pump oil in the refrigeration loop might not hurt? My delima is that I don't see how it got tree in the first place so I have no idea the level of contamination if it exists.

As yuri said there's nothing you can do about it now short of replacing the compressor and flushing the rest of the system. Might as well wait and see what happens.

You did not introduce a positive pressure and vac pump oil into the system because the valves on your gauges were closed. The only way that oil could get into the system is if you hooked up a bottle of freon and added some to the system to compensate for the extra line set if the specs required it. That freon would take the vac pump oil with it into the system. You have no worries if you did not add freon.