Flow Temperature settings of my Mitsubishi Ecodan heat pump set correctly?

The controller is in a hallway, large one. If wc is set at 35/-5 im not sure why when i changed heating mode to room stat the flow temp jumped to 48 degrees?!  I thought it used the wf settings in background somehow? 

I’m experimenting at the moment with a setback of just 1 degree from 9pm to 6am. The heat loss continues day and night of course, and usually the temp difference is greater at night so more heat loss then, and that’s when I get the cheaper electricity.

Usage pattern isn’t really relevant, the effect of people being in the house will add heat, opening doors will move heat around or lose it if an external door, but the hp will just tick over more efficiently if it’s left at a steady target temp.

Oooh, that does sound wrong, sorry out of my depth now as mine’s a Daikin. Can you post a pic of the controller screen and a Ecodan owner may help here…

@Jenp just lost an entire reply so here goes again: 

1. Get a wireless remote thermostat see photo.
2. Do not demand instant water heating via the melcloud app or the thermosat - this relies on the immersion heater. If you have it set to auto adapt (ie Room Temperature control) then it will heat the water when the water temp drops below a certain minimum. In my case it heats the water every 15 hours or so. 
3. Use auto adapt and get used to the idea of the pump running when it chooses, not when you choose it to.
4. Do not use timed settings. It is not a gas boiler. 
5. I have stopped using any degree of set back at the moment and the house is warmer as a result and the usage is about 20kwh a day for the whole house, not just the pump but the oven, tv etc etc as well. My Wireless Remote Controller is set to 19. Temps here in the Cairngorms lie between -18C and 5C or so in Dec through to February. We have had a couple of weeks of -10C or less and max total electricity consumption was 38Kwh. 
6. Expect the pump to cycle on and off every two hours or so on the coldest days.
7. Make sure your system has glycol in it and turn off the Freeze Stat function. 
8. Don’t demand tropical temperatures from it when it is minus C outside. These pumps struggle most around the 0 degrees C mark, and the hotter you want your house the more it’s going to cost you.

My ASHP is on auto adapt, my room temperature setting is 19C, my DHW is 50C with a max drop of 10 degrees before re-heating, my Dec to Jan bill was £200 with a standard variable Economy 10 tariff from OVO, but my bills in Dec-Jan before getting the Pump (ie with storage heaters) were £350 a month. The ASHP has nearly halved my annual electricity costs.

I also came across some stats from a research project in Norway, where they use ASHPs a lot, that suggested that having the DHW desired temperature at 35 or 40 meant that the COP of the pump increased in colder weather.

The more I read in these forums and on FB from local folks who have Heat Pumps, the more I suspect that people are trying to use their ASHPs as if they were gas boilers. I also think that installers don’t explain that if you want to “advance” the heating of the water, then it will be the immersion heater that does the heating, and this costs ££££. If you have your water on timed settings, and it drops low in temp during the off period, the ASHP prioritizes DHW heating and it will spend an hour or more getting the water back up to temp before it starts to heat your house. If your heating is also on timed settings, then your house will maybe take more than an hour after that, to get up to temperature. If you want it to be 23C in there, then it will definitely cost you!

Get a wireless thermostat, use Auto Adapt / Room Temperature Control, and let the pump do its own thing. Keep the wireless thermostat in a room that is reasonably central, and not drafty. 

Hey @Jenp,

Unfortunately, I’m not an expert in this area.

However, I wonder if any of the following Community Members might be able to offer advice: @Ecodanwarrior @James_N   @bgreenwood2000 @Cwriggers @Mimi @OrphM62 @Nicllb @amanda1 @Speps @zzzzz @New ASHP  

There might be some insights in the following topics:

It may be that the flow temp was 48deg because it was heating the hot water. Where did you see that value ? Do you have underfloor heating or radiators ? What was the temp in the house when you saw the 48deg flow ?

Thank you for your reply, i used to work in the gas heating industry so understand more than most i guess, i know this runs low and slow, so ve been running in comp curve at 42/-2… so generally runs 24/7 at about 35/36 degrees unless its freezing. Im happy with the running temp etc but wanted to investigate this Aa mode of running. I have solar so dont run anything on a timer as solar heats a tank during the day. Can you advise why i need the wireless stat.,does Aa only run with one of these and it wont work using main controller? Ive lookef at the settings and its set up for ‘main controller’?  I dont understand why putting my main controller on room stat mode it shot up to use 48 flow temp… isnt this linked to the weather comp? What is the benefit of another room stat controller please? This has confused me somewhat!.. many thanks, thought id sussed this ashp just using comp curve… im on comp curve 24/7 with no timer settings. I believe timer settings for hesting only work with aa/room stat mode and not beneficial for ashp that needs running 24/7 or it just goes on and off all the time?

Flow temp of 48 is in melcloud reports and on the controller initital settings, you can see the flow and return. Rads were red hot it was not the dhw as this is permanently off as i have solar.

Auto Adaption doesn't use the weather compensation curve you have been adjusting in the weather compensation feature.

Auto adaption will boost the flow temperature to get to the room temperature you have set. 

The flow temperature will adjust to as low as possible to maintain the room temperature over time. 

You would need to run the heat pump for a reasonable amount of time under both Auto adaption and weather compensation to see what works best for you in terms of comfort and cost.

For example you'll find Auto adaption reacts quicker when heating a home from cold.

Ah! Thats why flow temp shot up to 48…. Nothing to do with comp curve settings… interesting. 🤨 so thats really confused me as to how other ppl have told me to set the curve but use aa mode so flow temp is low.. one guy said set room temp to 28.. they must have individual room stats or something?! Thank you for taking time to reply, much appreciated