Why Don't Mini Splits Use a Liquid Line Filter Dryer? - Ask the Expert Episode 257

There are mini-split cleaning kits that you can buy that help solve this problem. Basically you put a plastic cover around and under the air handler. That cover had a tube that runs into a 5 gallon bucket. This way the air handler coil can be cleaned without getting mess all over your house.

Very likely you got this fixed already, but for those that stumble upon this at some point in the future... 1) Will it be missing oil? - Yes; but since the system was off, the amount would be so miniscule the system won't even notice. Unless - there was an oil streak(s) where the break occurred and you could visibly see it; additionally - if there was a significant film of oil all over your patio (as you stated there was a cloud of vapor around the patio which is likely just condensation from the refrigerant flashing at that point). 2) There are multiple dynamics of physics at play with your scenario that won't necessarily relate to all situations. 4 of the biggest determinations will be the temperature/activity of the oil, size of the hole/crack in the line, refrigerant vapor pressure within the system, and permeability of the material used to seal the line/break location. Time becomes irrelevant until the refrigerant pressures and atmospheric pressures reach the point of equilibrium. Ideally, you want to seal the system with something as solid as possible, with as little permeability as possible, as quickly as possible when safe to do so; thick duct tape will work in a pinch but not ideal. Depending on the break location, there could still be active liquid refrigerant being expelled through the hole/crack - do not attempt to seal it if there is visible liquid being expelled - recipe for severe frost bite/burn. Take note that some refrigerants are quite flammable as well when at their stoichiometric ratios with atmospheric air. For a residential system, it is best to just remove all people and pets from the immediate area and remain outdoors until the refrigerant vapors have time to dissipate fully in case there is an ignition event and risk of overpressure is high. Once you can safely reach the break and the service valves, seal the break as best as you can - taking care to not introduce foreign materials into the lines; and fully shut the service valves. The oil and refrigerant do not mix, they "foam" and froth to a degree, and that oil-bearing vapor is carried away, but should return back to the accumulator when the system is properly installed. Once a system is shutdown, the refrigerant will equalize as necessary, and the oil will fall out of suspension from the vapor. Any moisture that is introduced after the break occurs, and prior to being sealed, should not be damaging, so long proper techniques are followed to removed the non-condensable gasses; water/moisture will boil off as the vacuum is pulled and held. Now - if the system was fully running when this happened and no one shuts it down for an extended period of time, then it will very likely suck in atmospheric air/moisture and mix it into the oil; which over time and with heat applied, will turn it acidic. Your steps from there will be varied, but the unit will obviously need the broken location repaired before being turned back on. In general, any competent tech will purge the system with dry nitrogen to assess for any additional breaks/leaks and to assist with proper brazing of the repair joint(s). If all of that checks out then they will pull and hold a vacuum, and then charge the system by manufacture recommendations if the vacuum stats signify everything is good to go.