I could.
But I still won’t be able to run my Daikin heat pump efficiently at flow temperatures below 30c.
Which is the question I was answering about my radiators being too big.
They will still be too big.
But none of it is the end of the world, it works OK, just differently to how it’s intended to and how I planned for.
I do have an extra room I can heat, a large timber framed office on the back of my garage.
I have everything I need to do it except the enthusiasm!
We’ve been trying the hot water at 45C.
Quite acceptable.
If we had guests, or a third wheel, then 48C or a 2nd schedule would be required.
I got around to going through the hot water settings.
I changed the Maximum Running timer to 95mins, the additional timer to 95 minutes.
The anti-recycle timer I left on 3.
The schedule is for 1pm to 4pm cheapie time.
The priory was set to hot water anyway.
Do these setting seem okay?
I assume if it’s finished before 4pm it would go back to space heating?
I might also try a water temp if 48C on ECO mode and see how it fairs.
Hopefully I’ll see overall COP increase to the mid 4s again…
Yes it will go back to space heating when DHW gets to target temp within the time schedule.
Keep in mind that max run time do not count if
Control=Room thermostat and there is a request for space heating
Thanks @markr
I can set up a heating schedule for a few degrees below normal room temperature to ensure no space heating request.
Or, is it better to switch to LWT only? - I’m leaning that way anyway.
Or, does LWT control require a schedule reducing water temp to below the normal temperature during the hot water schedule to ensure there’s no way it can’t interrupt?
Having UFH means very slow decay of room temperatures even on the coldest of days. So no problem there.
Sorry for all the questions - steep learning curve.
I run full WC with LWT and am very happy with the results but all systems are different.
If you are on LTW the max time run is not affected by room temp.
I would also assume that reducing room temp would also work
The only thing with a manual set back is that the hot water could have reached temp but the schedule will be longer (to cover worst case heat up of tank from almost cold).
That gap would mean the pump spins down and then works harder once the heating schedule is back on.
Perhaps I’m over thinking this…
I’ll try tomorrow with space heating set back on schedule and see how it goes.
Then go full LWT…
I’ve been working through the formulas for kWh output etc. And I’m trying to see if I’ve made an error or not. Assuming you are running on weather comp at max, ie 45c flow rate and have managed to nail delta T at 10, so the flow rate has settled to 7L/m, then the max output I can obtain ( on the 8kw ( nominal ) altherma) is 4.88kw. So if I need more I would have to switch across to temp control and hope the system would push up the flow rate and hope that that gets ahead of the dropping delta t, to give more Kw’s any thoughts and real life experience to support either of those or something different. Thanks.
So I’m about to go LWT control.
I was wondering about how the heat pump turns off once the weather is warm, or if we get a particularly ‘warm’ day in say March?
Google AI came up with this answer
" When using the “Leaving Water Temperature Control” on a Daikin Altherma 3 heat pump, the unit will automatically turn off when the weather is warm because the desired leaving water temperature is reached, meaning the system no longer needs to produce heat to maintain the set temperature, effectively shutting down the heat pump operation."
Is this true?
What is the definition of turn off here?
What do LWT users do for summer?
It is not true.
The heat pump will no longer run when the outside temperature you set the limit to is reached.
Otherwise it will continue to run until you turn heating off and will not resume heating until you turn heating on again.
I do this from the Onecta app
Thanks Matt, I did wonder…
Good to know the Onecta App has control of Off/On still.
Don’t want to be getting to the MMI every time.
Will be nice to have LWT reductions scheduled at night and high tariff period to eek out a little more economy - and to get the scheduled hot water run on ECO fully completing to temp and then automatically going back to Space heating.
These two outweigh the hassle of manual intervention via Onecta to hard turn off/on once things are so warm heating is not required, I think…?
One day we may have it all🙂
You can adjust [4-02] in the installer field settings menu to the outside temp you don’t want space heating above. The lowest it goes is 14C, which is fine for me. At that and above, the HP is off for heating with no intervention on my part.
Yes John, that is what I said above.
But sometimes you may just want to turn it off, I am sure we will see this later from @HeatStig
I have mine outdoor temperature limit set to 30c!
I had to, because my remote outdoor temperature sensor is on a NW facing wall and at one time of day it gets some sun on it and records a much higher outdoor temperature.
I found this out when my heating suddenly turned off one day, it was about 10c outside but the temperature sensor was showing much higher and had exceeded the heating off threshold.
It took me a few minutes to work out what had happened as it was early days with lots of other issues.
can you add a sun shade to the sensor so the sensor is always in shade and dose not get affected by solar gain ?
is there way to over ride this if the internal temps drop to low , ?
As you can see by this chart I am having trouble with the HP and outside temperature ( current outside temp is 16°C:
Reading comments it would appear ( if you are running LWT and WC ) you have to adjust the settings for outside temp in the MMI and this should turn off the pump when upper limit is reached. Would the problem be deciding the upper temp limit, be a bit hit and miss as this time of the year as we do not get many warm days, so have to keep changing limit. Otherwise you have to manually turn off the HP through the Onecta?
Am I thinking correctly on what is happening.
You believe you have found a steady solution to running your HP and it throws something else at you.
No. Just don’t set it too low!! It’s unlikely you need heating at 20C external, given people, cooking, DHW cooling etc, so anything less than that that suits you. You could try to find the equilibrium temp, where the house is neither cooling nor warming given the usual inputs, it’s usually 15-17C.
What’s the internal temp you’re aiming for? It’s not on your graph here. If you’re above that, then you might consider setting the max external temp for space heating to 16 or 17, because you don’t need it, and then it won’t cycle madly.
At some times of year, a simple boost button that turn on CH for an hour with fixed flow temperature is likely to be best option.
our home has raised to 23 degrees today but dont want my flow temp any lower than the current 29 , so i have put the setting to shut off the heat pump at 15 degrees C and see how we get on
Thanks. My wife is not very well so I am aiming for 20/21°C in living room and 18°C in bedrooms.
