My old in-wall 12k unit has small metal tubes plugged into oil-holes that lead to the bearings.
Inside the tubes is a cotton string-like wick, that you add oil to, once a year.
I used to put 20 drops of oil in each tube.. It was a gravity feed system, and it worked..
Which reminds me, I've got to get rid of that boat anchor! And close up that hole-in-the-wall.
Maybe turn it into a heat pump! Use it to make hot water!
