Also where can I find info on these Daikin Altherma options?

And also wondering, where I can find info on these Daikin Altherma options?

Are you using control over the Leaving Water Temperature and also toggling on Weather Compensation? Rough and ready starting point as follows:

Set LWT to 35 degrees.

Go to the Weather Compensation settings, and set the slope  so that it is a few degrees higher than at present and possibly raise the minimum line on the middle point of the slope a few degrees so it makes the WC slope less steep. Tou can also raise the right hand side setting a few degrees so the the slope tails off at a milder temperature. Daikin explain this about as clear as mu with their graphs, X and Y’s - so I’m sorry if my directions are a little on the crude side - but what my directions will do is raise the various parmeters so that they will work at milder temperatures for you. Once warm again, try trimming back to be more economical with those Watts!. Regards, Toodles.

Thanks for the response!

I think in Daikin Altherma 3 the leaving water temperature is "Minimum set point"? After I set that to 37, our room is warm again.

Anyhow, I couldn't find setting for leaving water temperature.

Thanks again!

@aksel I have just remembered that another setting had to be changed by my installer some time back; when we went inyo March I think it was, I found that the heat pump was reluctant to start up in miler weather - though it was happy to run when the temperature dropped again. My installer checked th configuration and found that it had been set (by them) to cut out at +10 degrees and so milder conditions would make it shut down. I can’t remember the setting he adjusted but he raised it to something like +18 degrees and it was fine then. Regards, Toodles.

@aksel did you ever find a solution. If you did, please share it here.

Hi!

Yes, I needed to go to installation user and then set "Minimum set point" to 37, after that room is warm again.

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@toodles I read this with interest - I have a Daikin too and have been fiddling with the WCC forever. I like this approach (if I'm right in my interpretation) of setting the minimum LWT to something fixed, but also having the WCC toggled on. In my head this basically holds a fixed LWT above whatever outside air temp that corresponds to on the WCC; at colder temps the WCC would increase the LWT. Kind of a hybrid approach rather than just running on WCC? And as you say, play with the minimum LWT setting until you hit the right setting; the WCC will still control (i.e., raise) the LWT below that point. Have you compared the kwh consumption of this hybrid approach (if indeed that is what it is) with just running on WCC? My Daikin doesn't give me any consumption data so I have to rely on total grid consumption and break this down based upon what I know about my background usage etc from a few years of trial and error. Agree Daikin's manuals are almost impenetrable!

@marzipan71 I didn’t get round to making comparisons of consumption as we set up WC from day one. On our model, we can see the ‘consumption according to Daikin’ on the MMI and on the Onecta app. crude though it may be. As we had the Homely controller fitted last autumn, we no longer use the Daikin settings directly but just leave Homely to manage everything. With the mild weather we have been experiencing in the last week or two, we are staying cosy at 22.5 degrees C. 24/7 consuming approx. 0.5 kW/h.

Regards, Toodles.

Hi @toodles thanks for the update. My 16kw Daikin HT (run at LT) uses one of the old controllers - the next to useless EKRUAHTB - which gives me no information at all alas. I'm able to monitor grid consumption and then by a process of elimination estimate heating consumption vs everything else. You're obviously running at a great level of efficiency, and I may yet fall for Homely's charms. This heating season (since early November) we have been using on average 28.5 kwh per day for heating (inc. DHW) - either 1.2 kw/h or 2.0 kw/h depending whether I look at it as consumption over a 24hr period or just actual 'heating hours' when space heating is 'on' - I don't use setback. Actually, since our house is 240 sqm my daily heating kwh/m2 would be 0.1188; looks like your comparable figure would be 0.1237 (I think, using sq m data from your profile and 0.5 kW/h consumption) - however we keep the house at a slightly lower 21C...so doesn't look we are a million miles away in terms of efficiency? Looking at that another way - 240/97 = 2.5, then 12 kwh/ d * 2.5 should be around 30kwh per day for my house - so our average of 28.5 is about right. All good, unless my maths is way out!

@marzipan71 Looks as though we are in the same region for our heating needs (my DHW is separate as it is via a Sunamp Thermino) During the cold snap of -6 - 7 degrees C., our demand increased to approx. 2.0 kW/h - glad we don’t have too many of those days! Our house demand is approx. 10 kW/h and the Sunamp averages approx. 4.0 kW/h per day. This means our highest demand days reach about 62 kW/h - but they are thankfully, fairly rare! Regards, Toodles.