2 points to this.   1, having a clearer picture of how they work (2 months installed) I feel again the need to warn about them, or rather my vaillant one which is an utter disaster.   2, whether someone can help with a basic setting.   --   As I mentioned before, noise inside (not from the nice purring fan outside), is bad enough not just to be intrusive but aggrevating & impossible to live with. Noise eminates from the heat compressor outside > fed