Yeah, I know they come pre-charged now. But I can't remember what his problem was back then. Maybe he didn't know, or he fucked up…

From what I understand, self-install should be fine up to a 12m run, but if you let too much gas leak, you may have issues because of low pressure.

At least now you can buy them for relatively cheap. Mine required a swap of the control board on the inside unit, and it was ridiculously expensive (almost as much as buying a new unit). I am not sure why it fried, but probably bad solder from old age (it's about 15 years old at this point).

It's an excellent technology, but the surrounding business feels extremely shady.