Have you tried restricting the max pump speed? (Not just restricting it during sampling)
I don’t think you can?
our 8kW unit goes down to ~280W
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TBH I have not tried, do you know where this setting is within the MMI and does this also effect the DHW?
Ah RTFM, what speeds have other set?
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That’s good, thanks for letting us know.
So they are all the same I would assume in the 4 to 8kW range.
Mine goes as low as 860w if I really, really try!
But at least we have the extra 1kW of heat when we really need it, or maybe not! 
It really isn’t what you would expect.
I have now gone back to Madoka control of the room temperature on a schedule.
It will be interesting to see what happens.
I have shut all the windows now too!
I have a fairly flat WD curve with about 37c flow at 6c outside, I find it hard to judge exactly from the graph on the MMI, maybe I need to look elsewhere for the actual figures?
Overshoot is still 4c
Modulation is 2c as I had last time I used it in November.
I remember the room temperature going over that set on the Madoka by 1.5c to 2c
I don’t recall ever seeing anywhere to set by how much the requested room temperature can be exceeded by or at what point below that requested is heat called for.
I never wanted to run with a room thermostat, that is one thing I was hoping to eliminate by changing my newish gas boiler for a heat pump.
I just wanted heat dribbled in to match the heat loss of the house.
I can’t do that with this heat pump unless I control it myself with windows and doors.
Never have I been so disappointed with a product.
Now I just have the same as I had before, the only good thing is I am not burning anything.
It won’t be as efficient as I hoped for and I will still get the constant heating and cooling cycle that I really wanted to eliminate but I can’t carry on as I have been for the last month, it’s ridiculous controlling the heat with ventilation.
We’ll see how it goes.
Hopefully a week and a half running like this will give me some armament to make my case to Daikin next week.
I made a mistake in looking at the heatpunk schedule with the room temperatures I am aiming for (19C living rooms, 19C bathrooms, 18C bedrooms). I have configured the MCS design temperatures, and heatpunk shows a heat loss of just over 7000W.
So, I’m not (currently) thinking I want to take up the challenge of getting Octopus to swap the heat pump.
@KnightPhoenix I take responsibility for much of this. We recently had the bathrooms refurbished with “nice” towel radiators that fit the space and design and I was determined not to have those replaced by Octopus or my flooring lifted to fit an additional cheap towel radiator. Our towel radiators are fitted with “dual fuel” heaters and this seemed to satisfy Octopus and we could have the bathrooms left alone. We are satisfied with the temperatures our bathrooms are reaching and have no plans to change anything.
The survey showed the living room needed another radiator and the only suitable wall meant a vertical one had to be fitted, hence the large excess. It is nice and warm 
The hallway and kitchen are open plan, and open to the stairs. I don’t think they are as over-heated as implied, especially since the K2 in the kitchen is probably the last radiator in the entire system with a flow temp 5 or 6C below LWT.
I have three gripes with the radiator schedule and only one is Octopus’ fault:
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one of the bedrooms is a home office and was not given a target temperature of 21C; it was treated as a bedroom at 18C. I should have spotted that. As it is, it comfortably heats to our comfort temperature of 19C+ when I am working in there. (A human body and compute equipment go a long way to making up a small heat deficit
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The MCS design temperatures have a 3C difference between 21C living/dining rooms (typically downstairs) and 19C bedrooms upstairs. We find even a 2C different is VERY noticeable - you feel quite the gradient going upstairs. We’ve evened that out a bit, but I’d be surprised if people really want such a noticeable difference.
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22C for bathrooms required by MCS for bathrooms is luxurious but wasteful, IMO. The shower / bath does a great job of making up the shortfall in our bathrooms. Maybe I’m not using the bathroom right
I searched the installer manual for hysteresis, and found this buried in the Field Settings:
That’s all the information there is. I cannot relate 1C of hysteresis to the behaviour I’ve seen from the Madoka / system though! With a target room temperature of 19C, we see overheating to 20.5C and it doesn’t call for heat until about 18.5C.
My Madoka is set at 22c, it began heating today at 21.8c and stopped at 23.0c
It used as much electricity in 70 minutes as it would have done producing more heat in 2 hours and 20 minutes as I was running it previously.
I don’t have to concern myself with opening windows and doors by using the Madoka but now it is noticeably warmer and cooler in here as the temperature builds to 23.0c and then has to fall to 21.8c before we get heat again.
Just like my gas boiler.
Now it is at 21.6c and still doesn’t heat, I don’t get it, inconsistent and unpredictable.
It’s like a box of chocolates!
what I notice with the madoka and modulation, the system schedule is on 24/7 as I work from home.
our room temp is set at 20, it starts to heat at 19.5 and stops at 21.
I have changed the modulation last night and have the following results from 2 to 8 = a greater COP and a longer heat cycle with similar outdoor temps. The long consistent dip is DHW heating. Overshoot never changed and is 1 and WDC not changed.
note the average temp is from 3 sensors not the madoka exclusively
modulation of 2 - yesterday night - mean COP 3.84 inc DHW
modulation of 8 - this morning - mean COP 5.19 inc DHW
note the fluctuations are a dependencies of the sampling of the Daikin every 30 sec (ESP Altherma) and power measurements every few seconds (ShellyEM), that works out our COP, to maintain a flow temp the daikin modulates the power up and down -
Tick over power draw state fluctuates 250 - 450 W
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To see the effect of modulation on the control mechanism, I suggest you also plot graphs of:
Leaving water setpoint
Leaving water temperature
Thermostat temperature
Target temperature
Outside temperature
That set has enabled me to see the setpoint modulate with no difference in outside temperature, but as the thermostat temp approaches the target
In the case of the 9kW Daikin none of it matters if you are at 900w of electricity input and 4,500w or so of heat output.
You can’t do any better with it in terms of efficiency.
So, if like me, you don’t need 4,500w of heat continuously then you just need to get to 900w/4,500w as quickly and efficiently as possible to get it over and done with.
At the minimum input there is no benefit from reducing flow temperatures, modulating or anything else.
Things are different with the 8kW as you have room to reduce the electrical input much further, down to less than 300w.
The circulation pump in the 9kW uses more than half the electricity at times as the whole 8kW heat pump uses to heat a house.
At 90% I think the pump uses about 150w, maybe a little more. Looking back to my early days of heating I can see that the pump uses just over 150w at 20lpm
So far my return to the Madoka is going better than I expected, the new radiators have improved things immensely.
If I could get to 900w sooner and reduce the initial 3,000w power consumption I would be happier.
I run off batteries as much as I can and 900w is much better than 3kW as the higher power draw means I will be importing if anything much else is going on in the house.
The key to understanding the 9kW Daikin is the minimum power consumption, it’s just not very low and settings that work with the 8kW won’t really do much for this one, our options are limited by the inappropriate minimum output.
I will add that I speak from a position of the heat pump being too big for my house and so my views apply to those circumstances.
However, I suspect that this heat pump is likely to be too big for most of the homes it is fitted in most of the time.
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I still don’t know exactly what is making my heat pump turn on and off.
It isn’t the room temperature on the Madoka.
My set room temperature is 22c, it only drops to 20c between 00.00 and 04.00
The heating seems to come on between 21.5c and 21.8c, we don’t lose a lot of heat really so there is quite some time difference.
Yesterday I saw it turn off at 23.0c but now it is already at 23.5c.
I remember this from my previous time of using the Madoka.
Does anybody know what determines the temperatures at which heating stops and starts, it seems variable?
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Have you checked against the Daikin Installers Reference Guide, Matt? I just speed read this and you have far more knobs to twiddle than I do with my Samsung.
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“Smart” roomstats often anticipate an action (e.g. on/off) using 3-term control, and “learn” from the user’s past operating preferences (not always what the user intends!).
Hi Sarah,
I need to look again at the manuals although I don’t recall them going into sufficient detail about how much of it works.
It is one good thing (I think) about the Daikin heat pump and that is you can customise quite a lot to suit the installation, you’re right, a lot more to play with.
matt - just a thought for you. one user on renewable heating hub has positive results with homely’s controller and daikin. here. worth you investigating ? it does appear there’s an explicit setting for the hysteresis.
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Hi Ian,
Thanks for the link.
I read the thread and it’s very interesting, it’s something I would love to use.
The person concerned has an 8kW Daikin and that is very different to what I have.
The Homley system relies on being able to modulate the heat pump output to match the house and the electricity tariff.
I love the idea and it is really building on what I would like to do with my heat pump, I just want to run it continuously at whatever flow temperature is required to maintain a set temperature in my house.
I can’t do that at the moment, well not easily.
One way is to run at 900w input, accept 4,500w of heat and control the house with doors and windows, not really a great plan.
The other way is to run at 900w and drop the flow temperature as low as necessary to keep the house at 22c. I could do that but I won’t save any electricity because it will still use 900w, I will just have less heat and lower efficiency.
I am getting closer to accepting the lower efficiency but like many of us, I suspect, we want it to be efficient.
Whatever I do I can’t escape the fact that a continuous 4,500w of heat is more than my house needs or can take on all but the coldest days.
I either have to have smaller blocks of 4,500w as required or settle on a lower COP.
The heat pump isn’t really too big in theory. It is just the execution by Daikin, it has a compressor designed for a 16kW heat pump and a circulation pump that is for houses in the 250m2 to 600m2 range, not a 98m2 house with a 13m2 conservatory.
My circulation pump is using nearly 200w at times, that is nearly as much as the whole 8kW Daikin heat pump in the thread you linked to uses to heat his house at the minimum level.
As much as I would love it I can’t see any automation making what I have any better, my house is warm enough and I can’t use any less electricity.
Now that I am back under Madoka control it’s not so pleasant in the house, there is no heat for two to three hours at a time and I find a 2c temperature swing uncomfortable. In our conservatory the temperature swing is greater due to the higher heat loss.
The Homely would fix that but this is not a heat pump that is going to be happy turning on and off every 15 minutes.
Sadly, I have to agree with @marko, my installation was carried out by clowns.
I emailed Daikin tech support UK today to ask if they can improve modulation on the 9kW unit by lowering the flow rate and compressor speed, via a firmware upgrade.
I got a response quickly, but they said there’s some physics involved in keeping the pump running correctly. They want to look at my heat loss, emitter settings etc.
I’ll report back if anything new is learned.
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