Thanks to those involved in getting my overshoot back, I missed it and I am very happy to have it back.
It has solved many of my issues.
I have had the 8kW for nearly six weeks now and here are some unstructured ramblings.
It’s performed really well but I don’t like it very much being honest.
My main focus, as it should be, is on heating our house and it does that well, no complaints.
I have less heat than I did with the 9kW so that is really good and it uses a lot less electricity.
I like the heating on all the time when it is needed, I prefer that to the house heating up and cooling down with the heating coming on and going off, its just what I prefer.
I find it more comfortable, more efficient in terms of COP and very little difference in electricity consumption. We also like a warm house.
I never liked running the 9kW with a fixed dT using either fan coils or UFH, it worked best on radiators with a dT of 8c that I could never achieve at the flow temperatures I was running at.
Like this, the flow rate was on the floor and the heat output was determined by the flow temperature I chose and by the outside temperature to some extent. With the 9kW I just used to focus on getting the electricity consumption to 900w and dealt with what heat it produced.
With this 8kW I want to run on radiators but can’t really because the overshoot is fixed at 1c.
I can’t run as fan coils either for the same reason so now it is on UFH.
I don’t know exactly what the difference is between fan coils and UFH but I can see a difference.
What I don’t like about a fixed dT is that no one value is suitable for all conditions.
I don’t like the way the fixed dT is handled by the heat pump, it is not stable, the focus seems to be entirely on maintaining a return temperature with the flow rate and flow temperature changing erractically to do this.
I can’t help think this is inefficient, I don’t know why it doesn’t hold a flow temperature and vary the flow rate to maintain the requested dT, it always overshoots the required flow rate to be stable, it’s always over compensating.
My biggest problem though is the flow temperature I need to remain most efficient, the same as with the 9kW, I find I need to increase the flow temperature as it gets warmer.
I have found both Daikins to be really good when it is cold but difficult to find good efficiency when
warm.
For this reason I don’t use the Madoka.
One other problem seems to be my flow rate, my maximum seems quite low compared to others.
My heating system may be at fault or not the best but I even notice this when running DHW compared to others, there should be no flow rate problem here.
Although I can now lower my flow temperature I find the heat pump becomes unstable, the flow temperature decays dramitically and it just doesn’t work very well.
I could run at 29c last night but as it has got warmer I have had to increase the flow temperature to 31c to maintain efficiency.
It use less electricity at 31c when it is warmer than it will at lower flow temperatures.
I can only guess that the compressor likes some load on it.
Ultimately I will just have to move to the Madoka and leave it alone but I like to find out what is possible and what works best.
I still wish I had a Vaillant though.
