I have been reading through the length Grant thread and saw in this post that there is a limit of 25 on the standby pump option and 30 on the minimum
I can confirm after updating my minimum to 30 the flow rate immediately dropped from 18.33L/min to 13.3L/min
The compressor also seemed to immediately work less hard, despite outdoor temps continuing to drop - so reducing the minimum flow rate has improved the efficiency? Makes you wonder why it has a default minimum of 50%… delta T remains the same at around 3c
I also really don’t understand why when the heat pump is idle for a long time it doesn’t stop pumping water. I may ring Grant this week and ask.