Waking up. Everything cold. Checking heat pump.
System says "everything bad". Checking error code. Checking outdoor unit. Marderschaden! (=Damaged by a weasel!) That's new.
Reparing. Yay! Working again.
Saved roughly 300-500 euro in costs (and a weekend with only cold water!), and the wife is complaining that I cut her 2 Euro USB-cable for that. Argl.