Smarter people than me made more sense of it in that thread.
The key to understanding and getting the most out of this heat pump is the minimum electricity, once I knew that was the limiting factor the rest just falls into place.
I now run mine at whatever flow temperature gives me 900w and accept the heat produced.
It’s odd because sometimes, when it’s warmer usually, the overshoot kicks in and the flow temperature rises with no extra electricity, the heat output goes up and therefore so does the COP.
I think this happens as the house temperature rises and the radiator dT of 8c kicks the overshoot into action.
It’s always a battle, you get more heat than you want but the COP is better, what to give up?!
I was striving for better COP at one point, just to prove to myself it can do it, but I have given up now, it’s uncomfortable and a waste of time as it uses no less electricity, you just get more heat you don’t want.
One other big thing is the initial start up, the first 60 minutes or so came at a much lower COP which meant I always wanted to keep it running as long as possible when it was running at a decent COP. That becomes uncomfortable.
I have limited my pump speed to 60% so it never goes above 15lpm when heating starts, it doesn’t affect DHW. It makes the whole process softer and less aggressive, the COP is much better and I feel much happier running in shorter bursts.
So, I run as radiators, overshoot of 4c, no Madoka and therefore no modulation, no wdc, always a fixed lwt and the pump limited to 60%. Fixed lwt set to get 900w of electricity consumption.