Hot water and heating control with my Mitsubishi Ecodan Air-Source Heat Pump (ASHP)?

Hi there, new to all this, and just had the heatpump installed and I've tried to find out answers to my questions but not getting much help!  So hoping someone here knows more 🙏   I tried to post a question as a new thread but it is not easy to do....so replying here, in the hope someone can help me and it gets read?  Many thanks.

So my heatpump setting and hot water setting are both on standby, but I assume it is the pump in the cupboard making a noise (running) fan is not running, and from what I've read here, this is because of low outside temperatures and to stop pipes freezing?  My question is, is this costing me money?   If I have my heat on (it's not off, just i have temp set lower as I have a chinchilla and we don't like it too hot) would that reduce the need for the pump to run on it's own?  On days like this week we might have some heat running first thing and after 7pm for a while, I imagine when it's very cold like tonight I'll leave it on say 15, so it would probably come on and off during the night.  I usually have it set on 16, when I want the heat on, room temp is usually between 15-16....and having heat on to go to 16, actually heats the bedroom to nearly 18, which is fine but I don't want it higher than that.  I should say we are in a one bed bungalow and boiler and pump are in living room pantry which backs into the bedroom.

The other thing is the hot water seems to heat everyday, I also read on here, the water heats up when it drops 10 degrees from set temp.  I have no idea what that set temp is....but I've seen the temp on the panel as high as 59, and as low as 43.   I cannot change these temps.  It is too hot for me as I only use hot water for hands and washing up as I have an electric shower and no bath.  I feeling such a waste reheating everyday.  I did ring the tech people, they said putting it on a timer would cost me more?  Is that right?  When I switch to octopus cosy tariff I dont want it turning on between 4-7pm as it will be way more expensive then!  So I'm unsure what to do there, and I recall the installer saying after initial setup water is free, not sure how but is this reheating costing me, it must be?

I'm sure I had another question but I can't think what it was at the moment!  But if anyone could help that would be great.

Thank you 😊 

Hi @Auds we will help !! Can you tell us a bit more about your system: is it an Ecodan or another make ? Can you post a photo of the controller screen so we can see how it’s set up. Where are you in the country ?

You can definitely change the hot water to heat to your own requirements and it is better to not heat to above 50 degrees, which would be more efficient with a heat pump (hand hot is nearer 42deg I think). Your installer probably set it up to heat it to 60 deg once a week to kill off legionella, but the general feeling is that it is not necessary in most cases. If you were storing hot water for use in a care home or hospital that’s different, but showers are the most likely place where it occurs and as you have an electric shower it isn’t relevant.

Hi Juliamc,

Just sent photo of control panel as it is now.  Water was 61 a bit ago!  Burn my hands lol!  Yes it is an ecodan.  I'm in Staffordshire.  Ahhh that may be why its heated to 61 today then.  But it also heats up everyday as and when it likes, whenever the temperature of the water drops to 40-40 something.  I feel that's such a waste of energy.  

@amanda1 will explain the controls (mine is a different make so not much help here). She also had her room temp cool like yours - I’m a soft southerner and mine is 22degrees. You’ll get a very efficient system running it around 16 to 18 deg*. Although it seems wrong you could leave it at a steady temp all night and day, like you would the fridge. Then the heat pump will tick along nicely. It’s the stopping and starting up again which makes it inefficient.

Each time it heats the hot water it stops sending heat to your radiators, so it’s best to schedule the hot water at a time when you will least notice. Mines done at night (00:30 on cheap rate) and at 14:30 when the outside air is warmest so more efficient. You’ll probably only need one heat up and on your system you can set how long that runs for.

*your system would probably have been designed to run at 21 degrees indoors so it may not be efficient to run it at your low temps. I’m only basing that on stuff I’ve read as I’m not a real heating engineer!!! I may well have misunderstood.

Hi, thanks for info.....I'm still unsure how to actually set everything and can I change the setup 21degrees as if it will never be efficient then what is the point of having it? I told the engineer I don't want it hotter than 18 due to my chinchilla and that we don't like it hot, so would have hoped he'd have listened to me.  I did see 23 on the control at one point the day he was doing it all.   I think I'm going to have to ring Broadoaks and ask them to send out an engineer to go through it with me and set it up to my preferences.....I can't afford to be paying silly money for something I don't really need to use that much really.  I had no choice in having the system as I'm in council property.   They installed solar too, but I don't think they are working as the app shows no productivity at all.  I'm anxious and annoyed.  I'm all for green energy but I need to understand how to use it and keep cost down and heat low.  Thanks for your replies though, appreciate it....could really do with an engineer coming here and going through it properly with me as I didnt get anything other than very basics explained.

The installer should explain the controls but when it’s all new it’s difficult to remember everything that’s said. They have a habit of saying it’s all set up for you don’t touch anything (that’s what mine said). If you told the installer you wanted 18 that should work fine, ignore my prev comment!!

There are some videos of Ecodan controls which are useful, just to get a hang of what’s possible. I’ll get some links…

Let's start with your hot water. At the moment it's set to reheat when the cylinder temperature drops. Many of us find that inconvenient so we change it to heat the water once or twice a day on a timer. Have a look on YouTube for instructions on how to change the settings.

Next, your hot water is probably hotter than you need. Turn the temperature down (again, instructions on YouTube) until it is just hot enough for your needs. I think ours is at 50 degrees.

This video shows the three heating modes that the Ecodan can run. @Auds  yours is running on Auto Adaptive which is shown 2mins 10secs in. It will vary the flow temp (ie the temp of the water in the radiators) depending on the outside temperature. Your installer would have set the weather dependent graph already. As the video shows, you set the room temp you require and the system will adjust itself accordingly. Your best bet is to set it to 18deg and leave it like that night and day. 
Have a look at that and report back !! Meanwhile I’ll see if I can find more about setting the hot water.

Lots of people find auto adapt mode to be the most efficient way to run an Ecodan heat pump. Don't be tempted to vary the temperature too much during the day. As Julia says, it's better to set a temperature and leave it although some people like it colder at night so it's okay to drop it a couple of degrees.

You mention switching to Cosy Octopus. If you do, you can heat your water and warm the house during the cheap periods.