FrankG

@JohnMo, @ReedRichards and @Temp, your questions lead to a small test I just did. Attached picture says it all - the temperature of the heat pump / hydrobox does not get above 44C!? Already after 18 minutes the heat pump stops. Not sure why. The operation time is set at 60 minutes, max temp at 50C. What setting (FTC or dip switch) could be wrong here? What's next to test?

@JohnMo, my house (so also the whole installation) is new - installed in 2020. See attached the plate of the boiler (sorry, in Spanish ...)

@TW9I just ran the experiment: set max temp from 50C to 55C. Heat pump stops again at 38C (the power consumption go down), and the FTC shows on the display that the immersion starts (see attached picture). I also tried to set the DHW (hot water) mode in Normal, or ECO - does not make a difference ... What I do notice in my power consumption (I have solar panels, so I can see this almost real-time) is that the heat pump only uses 1.3 kW when in use. I remember in winter that this was a lot higher!?

@JohnMo My cylinder (I assume you mean the cylindrical boiler) gets its initial heat from the hidrobox. And it has an electrical immersion heater (that should not be needed in summer). Where can I see the flow temperature? @LA3222, i read the user manual twice, compared notes and all settings with the installer. I guess I will have to read the Service Manual now? @Dan F My hidrobox is the Mitsubishi EHSC-VM2D.UK.

My Ecodan only heats the DHW (Domestic Hot Water - in the boiler) to 39C by using the heat pump while it is 30C outside. I have to use the immersion heater (= pure electric) to increase the temperature further!? My installer tells me that this is normal, because heat pumps are designed/optimized to work in moderate temperatures. To me this sound not very logical. I've read the user manual, service manual, but did not find useful/relevant information. Who can help me?