Beef

Hmm, I might try tuning the hysteris then, see if that has any impact.

Ok, so I have data in home assistant showing the in/out water temps, plus the amount of electricity it's consuming. I have a separate meter for the heat pump (and another for the immersion), and I've confirmed that home assistant is pretty accurate with what it's recording So can I somehow calculate SCOP from that? In these cold days it's running 24/7 - I only have the reused Nest acting as an over-temp cut off. Interestingly, my pump gently cycles up and down during the day; it's not the defrost cycle as that looks different, but I've attached a screenshot showing what I mean. It's not causing any problems - the house is warm - so I'm figuring this is just hysteris, but would like to confirm. Thank you both for your advice and help, it's really appreciated

I see, that's unfortunate. How do I determine the actual seasonal COP? I want to be sure I'm getting the performance quoted Thank you!

I have a 16kW Therma V, installed in the summer. I'm happy enough with the result - house is warm, water is warm, but I can't see how I can tell/monitor what the COP is on the installation. I've looked through the control panel, and the app, but nothing stands out. Is there a way to monitor the COP, or have I misunderstood a fundamental concept? Thanks in advance