I dont think the Mitsi COP estimate is very accurate. Mine shows a lower COP than my measurements with proper heat meter. The Mitsi system uses a vortex-flow sensor and might be using the strap-on sensors… not certain. Anyhow, my new and old units do what it says on the tin, BUT my new one does these strange dips in output when on low load (as graph). here the average heat output is around 3kW… It should do that in steady state. COP here (in ideal conditions, 7 degrees out) is 3.94, but the tail end 17:32 to 17:37 is COP 4.5. I think it should do steady state with better COP than it is. I don’t know if you are getting these drop-in-output issue too, or if your COP estimate is low
