The problem is, if your landlord ever comes around for inspection, or the bloody thing breaks down due to your installation attempt, you can be held liable up to and including getting evicted.

Where can you get evicted for something like that? The worst case is that they would sue your insurance for damages, or you'd have to pay them out of pocket.

Probably half of the US, but messing around with stuff like boilers can and will lead to issues even here in Germany.

Many countries have no contest evictions, so you could even get evicted if the landlord doesn't like your cooking.

That was my first thought on how I would approach it as well.