Ecodan 'Coeffeciency of Performance', can I improve it?

Thank you , very helpful. The homely device would be handy and something i would be interested in. So i just completely ignore the thermostatic now.  I did have mine on  auto adjust mode, but i noticed (although the house was warm etc) the pump/fan was off a lot and the COP was 1.48 for March.  This morning the fan was on but not rotating too fast.

I check how the cop is doing on my Daikin by recording the input and output values every day (I may be a bit obsessed). If yours is running slower and more consistently now you should see an improvement in the numbers straight away,

 I might just do this too!  So you’re technically doing a daily COP and what are you hoping for? Anything over 2.8?

It did get to an average of 3.47 in May 2021 but something happened which meant it dropped to 2.25 on average over the winter. My installer is due to check it out soon. The best it’s been recently on a warm day was 2.95 for the heating. I’d hope it could get to 4.0 as that’s not unusual for a heat pump, some reckon to get 5.0 or more.

Wow 3.47 seems excellent. And should the COP remain static through the months or do you see fluctuations?  How do i improve the DHW Cop? I have it on constant Eco mode and its 1.48 COP in March.

It’ll definitely fluctuate throughout the year. Not sure about your dhw 1.48 not very good ☹️

Do you keep adjusting it throughout the year or leave it alone once you found the temp that suits your house? I know i don’t touch the thermostats when on this mode but do i use them as a guide to know what temp the house is at ? I.e i could find at 23c is comfortable and then end up with huge bills getting to that temp!

On the question of dhw cop (sorry one question behind) 45 deg is good and low so no prob there. I heat my hot water two times a day - at 3am and 3pm. The 3pm is generally the warmest part of the day so I don’t miss the heating then (as the system only does dhw or radiators but not both together), when the air is warmest outside the hp is most efficient. At 3am it’s less efficient but suits me as heating not missed then either. If you have a cheap rate electricity tariff then that’s a good reason to heat the water during that time. 
With solar panels of course the time to heat the dhw is when they’re producing lots of free energy, so it doesn’t really matter what the cop figure is.

When you say ‘constant eco mode’ is that reheating throughout the day ? I’d switch it to a schedule eg like mine, I think you have to specify how long it’s doing dhw so that’s prob trial and error depending on what volume it has to heat etc. Mine takes about 50 mins in the afternoon to get to 48 degrees.

The goal is to keep the house at a temperature that you are comfortable with, 21 degrees works ok for us, though I’d love it to be 23 that would be extravagant.

On a sunny day we get lots of solar gain in the mornings and because our system has ‘modulation’ (maybe similar to your auto adapt) it decreases the radiator water temp according to the temperature sensor in the house. Nb this is not the same as a thermostat which is basically an on/off switch triggered by a temperature setting.

Having said that, in the summer the indoor temperature is generally higher than 21 degrees and the heating doesn’t come on at all. I think that’s because the weather dependent graph would set the radiator water temperature to less than the minimum for the system, so it just doesn’t run. I never actually turned the heating off last summer.

 The thing you will be tweaking will be the two ends of the weather graph (it’s a straight line so no idea why it’s called a curve). You should set the room ‘thermostat’ to higher than your target temp so it doesn’t switch off the heating, and just use the graph to set the radiator temperature. All sounds a bit counterintuitive I know…!

As @M.isterW mentioned earlier, not sure how having 2 thermostats affects this ??

Good luck ! Let us know how you get on.

Maurice Kelly Why would you want the ASHP to be running after it has reached the desired temperatures? If the pump ran continuously you would be paying astronomical bills… My Ecodan was fitted at the beginning of May and although I am super pleased with having hot water on demand and heat in my home within about 15 minutes of demanding it, (compared with my old storage heaters and Horstmann water control), the COP isn’t brilliant, about 2:1 at best, 1.5 average. COP is not a critical factor for me (as long as it is ‘t negative….!) - any savings are a huge bonus - but it bothers me that it is supposed to achieve 4:1 in summer conditions and it only achieves 1.5.

It is set to Auto Adapt, and it is not set to timed settings for either heat or water. This is logical for our wintry conditions here from November through to April,, because if it were timed, it would spend ages cranking up the hot water temp before the heating could kick in, and then it would spend ages cranking up the heating from cold. 

I am finding that as I have used the heating occasionally in the past couple of weeks, it has been slightly more efficient in correspondence. Obviously it will consume a certain amount of electricity even for minimal use, and it appears that that baseline amount of electricity is 2.5Kwh a day. That gives me hot water on demand, but no heat, as I don’t require it. If you don’t require it to deliver heat often, as in the past couple of months, then it isn’t going to achieve a COP of 4:1?

I find that if I want heat I just flick up the target temperature on the indoor thermostat by 0.5 or 1 degree (I have it set at 18 at the moment, 17 at night) and the ecodan soon kicks in, brings the temperature up and then stops, kicks in again if the temperature falls below the target temperature. If it kept running after reaching the target temperature, I would be worried…

I have big radiators with thermostats that are all set to open, one zone only, and the water temp is set to 50 with 40 as the trigger temperature for water heating. On this setting the water heats up about once every 12 to 15 hours. I have fathomed out some of the settings, but I was left with zero information by the installers, so it has been a learning curve.