Hi Peter. Welcome to the forum. I too have a the Ecodan but the 14kw. Can I ask, do you have the package with the pre-plumbed cylinder?

@hjd no we don't, we have a 250L tank made by a company called Telford.

@peterr your energy figure, is that heat delivered or heat used? I ask because those are two very very different things. It makes more sense for that to be delivered heat. a COP of 1-2 is pretty low especially if you have underfloor (which needs less heat). I have rads and I am running at 3-4 at the moment and I'd say my weather compensation is very similar 50@-4 and 25@16

I agree with @batalto - your KWh figures @peterr look like they could be delivered rather than consumed. For comparison, mine is about 300kwh consumed and c. 950kwh delivered as of today.

On weather compensation, that is what I currently have running and it seems to be coping well so far but as you say, we haven't really been tested (yet) with dropping temperatures. 

In terms of pumps running, I have the same situation. If you have zoned UFH / Radiators the pumps will run for as long as the thermostats are calling for heat. However, in weather compensation mode the main circulating pump is switched on and off by the FTC unit linked to flow temperature. So at times they are out of sync with each other.

I believe that the suggestions elsewhere on the forum would be to remove the zone manifold pumps and actuators completely and have a single run system all at the same temperature and let the FTC and the main circulating pump deal with everything using just the weather compensation mode (or the auto adaption with the additional remote room sensor) ..... but I haven't been brave enough yet!

@peterr,

We have a 14kWh Ecodan, 160m2 bungalow. 21-22C throughout, all radiators.  From 1-18 Nov we used 330kWh heating and 30.2kWh HW.  For the first week of that time I was using the thermostats to control room temp and weather compensation for flow temp; since then only weather compensation with thermostats at 30C. My compensation curve is similar to yours. Yesterday from 11am-10pm we were using an average of about 0.5kW for heating, also with ASHP cycling every 30-40 mins.  I don't know my COP because it's not recording properly.  If a lot of your use is HW your COP won't be high. Less than two sounds very low though. 

You may find the cycling will stop when it gets colder. At the moment, because it's mild, I think my ASHP's minimum output is heating water faster than the radiators are emitting it, so it runs for a bit, hits the weather compensation temp, stops while the water cools then repeats.    My ASHP stops cycling at 7-8C outside temp.  It then seems to run at at its minimum continuous output, at which time it's using about 1.2kW. Cycling twice per hour isn't going to do any harm. 

It does sound like one of your energy recordings isn't right. Are you using the Ecodan controller's energy consumed?  I always found that matched Melcloud very closely.      

I don't know about the pumps, sorry.

I think weather compensation is better than a set flow temperature although it takes a bit of experimentation to get it right.  Whether it's cheaper for me to turn the heating on and off with thermostats or run it 24/7 I don't know yet.  The Ecodan FTC5/6 controller also has a feature called auto adaptation, which uses room temp and weather compensation but it doesn't appear to work with 3rd party thermostats.    

@batalto unfortunately those are consumed figures 😳 

Consumption summary from the app:

 Detailed consumption on a daily basis:

And delivered energy on a daily basis:

To me the figures look pretty horrendous, which is why I made the change to Weather Compensation mode about 2 days ago. Yesterday's figures will include a good amount of energy consumed with the heating on constantly to get the UFH slab up to temperature.  Hopefully the daily figure for today will be a lot better!

Posted by: @hjd

I believe that the suggestions elsewhere on the forum would be to remove the zone manifold pumps and actuators completely and have a single run system all at the same temperature and let the FTC and the main circulating pump deal with everything using just the weather compensation mode (or the auto adaption with the additional remote room sensor) ..... but I haven't been brave enough yet!

This is essentially what I have just started doing.  I have turned up all the stats so that they are constantly calling for heat and just letting the weather compensation set the flow temperature.  It seems to be working well so far - 48 hours on from making the change and the house is sitting at a fairly constant temperature.

It took me a while to pluck up the courage to make the switch from room temperature control to weather compensation - it was looking at our energy consumption that finally gave me the push I needed 😀 

@kev-m 

Most of our consumption has been heating, I think it has been so high because we were using room temperature control, so when the UFH started calling for heat the ASHP would expend a lot of energy heating the slab up.  When the room reached the required temperature the ASHP would switch off, letting the slab cool back down again, while the room still stayed fairly warm.  Only when the room dropped below the stat temperature would the ASHP kick in and start the whole process of warming the slab up again.  I am hopeful that now the slab is up to temperature it won't take as much energy to keep it there.

The same is probably true to some extent for the rooms heated by radiators, they were constantly heating up and cooling down, so the ASHP kept kicking in to get up to a 50 degC flow temperature.

@peterr your house size is about the same as mine. Given you've got UFH you should be using less power. Have you done a heat loss assessment? How well are you insulated?

Ours for the same period.  Our house is a lot smaller than yours though. The peak on the 7th was changing to weather compensation.  That heated up the whole house to over 23C before I lowered the curve.  I'm sure you're going in the right direction.  Ignore my COP (obviously!)