@bontwoody scop of 3.2 is certainly achievable, but not very easily on a retrofit unless you design for 45 degree flow, maximum. With octopus (for example) designing for 50 (nothing wrong with that), I expect we’ll see quite a few systems running at 3-3.5 ish.

It isn’t as clear cut as it seems…. And yes I probably was generalising massively with my statement.

@bontwoody Togfather, my Daikin is basically based on WC as seen by the Homely controller; here is a graph of OAT for the last week working at 22.5 degrees C throughout the whole house. (Yes, we like it warm) with a COP of 2.64; the temperature has ranged from 6 degrees to -4 degrees during this time. When we have perhaps 6 -8 degrees, the COP is over 4. Regards, Toodles.

@togfather so unfortunately we have heard a lot of cases of Eco4 installs using several methods that are bad practice for ASHP installation, all at the same time.

 can see a flow rate of 10 l/min in your pictures. That could be part of the problem as thats way too low to move 11kw, at the DeltaT (DT means difference in temperatures between warm to the radiators and cold coming back) needed by a heat pump system (DT5). 10 litres a minute only moves 11kw if the DT is 15. DT15 is not going to work on a heat pump. So the effect is that if the DT stays at 5, you're only moving 3.5kw, which is almost certainly not enough to heat your house in freezing weather, which is (at least partly) why you're cold.

So you need to get the flow rate up:  Can you post photos of your system, what circulation pumps do you have and what setting are they on?

the fact your're only moving 3.5kw and its still costing you loads suggests as others have said that a backup resistance heater (basically a 3kw immersion built into the heatpump as a BACKUP - not for permanent use) may be running all the time

@ other daikin users on here - can someone please advise the OP of config parameters for WC, and how to check if the resistance backup heater is running and configure it not to?

do you have TRV's on your radiators? If yes, please open them all up to 5 , or remove them. you also mentioned multiple zones - please make sure both zones are always on - are they controlled by the external stats? if so, set that stat higher than the current temperature. But those can wait as I think the flow rate and backup heater (see above) are the first priority.

Do you understand what weather compensation is? This controls the setpoint for the water in your heating system according to how cold it is. The colder it is outside, the warmer the heating water, and vice versa. This is absolutely essential for an efficient system. It appear your system is not configured in this mode. 

can you just get your installer to come back? tell him what you've said here, your house is way too cold, its costing you lots of money - clearly, they haven't set it up properly.

@hughf Ok Hugh, thanks for the explanation. Flow temperature certainly is a big factor. Personally I wouldnt advise anyone to go for 50C flow.

@iancalderbank Good spot on the flow rate Ian!

@bontwoody Togfather, if you wish to try using Weather Compensation and are unsure of how to start, may I suggest that you tap the left hand button dial on the MMI and scroll to user profile and tap the button then select ‘Installer’ by tapping in the code 5678 - this should then give you access to all the settings menus? You should now be able to scroll to Main Zone, select, then scroll down to Weather Dependant, select, then you will have the ‘curve’ displayed ready to set. Adam from Heat Geek made a You Tube presentation about setting up WC which I’ll go away and find and post the link shortly. Regards, Toodles.

Togfather, I have the Heat Geek link for you:

I mentioned using the user profile setting of installer as I can’t recall how much access the default setting access allows on each menu; I don’t wish to alter any settings on mine as Homely might smack my wrists for interfering! 😉 Have Fun and I hope this warms you up and lowers your bills!

@iancalderbank I did complain and got the installer back, together with a Daikin sales engineer. They both said that I should not use the WC setpoint sytem, as it would cost me more money. They also said the system wasa set up correctly, with no mention of a backup heater.

Both were very courteous and friendly, but I am sceptical because the installer is giving Daikin a lot of ECO4 business, who therefore has no motive to be impartial or in favour of me.

So, I now have two questions.

Should I turn of the backup heater, and if so, how do I do that?

What settings should I use for the WC setpoint to experiment?

Best wishes. Tog 🙂

@togfather Togfather, the settings as advised by Adam Heat Geek will be a good starting point - you can tweak them later if required. I know nothing of the 3 kW heater settings as my pump doesn’t have one but I suspect it is within the Installer Settings for which you will need the user profile - code 5678 to access. When you enter the installer settings area, you will find many options and there should be one for back up heater (or some such name) did your installer leave you with a manual for the Daikin? This is fairly heavy going in places but is detailed and may assist in the settings. Regards, Toodles.

@toodles Thank you for this. I will give it a try 🙂

@togfather Go and check whether the back up heater is running. See attached pictures. You need to go to the actuators menu.

@togfather They said using Weather Compensation would cost you more money to run? This just gets better! 😆 I am gobsmacked by what these installers seem to get away with.