A lot of stuff is missing and can only be found in the field code list at the back of the manual.- field codes 8-00 and above for example.
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I found the settings OK and have looked at the list, but there is minimal/no guidance on many settings.
They are only accessible in installer mode and I assume you are just supposed to know, if you donât leave it alone!
Trystan installed a P1P2 monitor which reads all the Daikin data. I just connected it to the two wires into the Madoka - I think he has referred to where he found it early on in this thread.
OK, I will look back.
Espaltherma adds a `readerâ into a connector on a board inside the heat pump and can retrieve all this data. Itâs just HA is not in my skill set and I almost had it installed on a standalone pc until one piece of software corrupted my Sandisk usb drives. I have new ones from a different manufacturer and should have another go.
Thanks.
What is your heat loss Colin?
9.8kw at -2c calculated and empirically checked when I had the gas boiler. It was -2 ish outside for a week and I limited the boiler to 11kw and it kept the house just warm enough.
It was then I realised that the original plumber had installed a 37kW gas boiler which modulated down to 11kw !! So I was very wary of the HP people doing the same gross oversizing. In the gas boiler case it was oversized by 400%!!
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Page 176 in the installer ref guide does mention the 9-04 overshoot. I have yet to find any mention of 9-0C the room temp hysteresis. Mine is set on 1. You could try increasing this to see if the comp stays on for longer - at the expense of a house temp variation which you might feel.
I just record any of these changes in a small log book so I can readily reverse them if I mess things up.
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I think Octopus calculated my heat loss at 7.3kW/-2.3c outside/21c inside
But then I also saw 6.5kW somewhere.
It includes a conservatory that I would shut off if really cold, just because we can although the radiator was plenty big enough with gas so we kept it open except at night.
I donât think the heat loss of the actual house is very high, somewhere between 4 and 5kW is what I calculated.
House was an EPC of B/89 when we bought it two years ago.
I have always had the house warm and it had an 18kWh Vaillant boiler with a vented tank.
On the worst day last year we consumed 110kWh of gas and that included heating hot water.
Assuming 90% efficiency of the gas boiler and ignoring hot water our house lost 100kWh in 24 hours I remember the day and it was about -5c all day on average.
With that being the case I think our heat loss is about 4kW at the design temperatures.
The heat pump is too big, I am pretty sure of it.
A similar worst day using gas for us was 180kW gross so probably 160KW into the house at approx 19C average room temp
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Itâs easy to use a USB stick in the MMI USB port, and use Export the settings in Installer mode to export all of the settings to the stick. Itâs just a text file - db-export.ini, and pretty clear what all the settings are, including the âmagicâ ones like [09-04] - at least, as clear as the manual is!
Then you can look at them easily without going to the MMI all the time - mineâs boring to get to/look at.
I donât know why we donât use this facility more often to compare settings in a more systematic way.
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In my experience your unit (and mine) will probably produce about 7.3kw at -2.3 due to the defrost cycling every 35 mins. So the question is do you want to pay more in Spring and Autumn for a lower efficiency unit OR need supplementary heating for the few Winter days when that really is the AVERAGE temperature? Installers always opt for a much bigger unit and probably always will in the future.
I think you are correct Colin, given the choice of a smaller Daikin or the one I have now I would probably stick with what I have. I am sure that it will be able to heat our house however cold it gets and the performance now is not disasterous by any means.
However, COPs of 5 are quoted at these flow temperatures and outside temperatures. I feel a bit misled. My documents quote a SCOP of 4.36 at 35c flow temperature. Iâm never going to see that.
My biggest issue with it all is heatpumpmonitor.org. Here I can clearly see what I could have had!
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My house has been at the same temperature pretty much constantly for the last two weeks.
Looking at my data I could say that my heat requirement at around an average of 10c outside and 21c indoors is about 40kWh at most.
So that gives me a heat loss of 1.7 kW.
Assuming a linear calculation my heat loss at 21c indoors and -2c outside is 3.55 kW
Nowhere near 7.3 kW, itâs not surprising that I am struggling with it.
Just looking at the first 12 hours of today. 17.287 kWh of heat required to maintain 20.6c in the house with average outside of 10.9c. Heat loss is 1.44kW which translates to 3.4kW at 21c/-2c
Iâm currently running my âIpswich Simulationâ âŠAt 10:28 I switched off my 4 fan convectors and at 11:10 switched off another large radiator so I am down to maybe 30% of my radiator capacity. In theory Basingstoke should now behave like Ipswich⊠except that I am freezing in here and have just added a fan heater!
It has just started cylcling;
As you can see the COP (black line) has dropped from 5 to 4, the compressor was using the same amount of power (minimum setting) but only heating a small part of the house
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Thanks Colin.
Itâs very interesting.
I called Octopus aftercare a while ago and an engineer called me. We knew each other as he had done a post installation check at my house in July.
I was asking him about fitting an OEM system but he though it was unnecessary and that I should just run it like most other customers do.
He thinks my heating COP was good and better than most others he sees, that doesnât really make it better!
I explained why I thought the heat pump was too big and he says he is going to talk to somebody about getting it resurveyed.
I also asked why it was setup with fan coils when I have radiators and he said that is what they usually do. I couldnât get a reason for this.
I also mentioned the other heat pump data I have access to , like the 8.6kW Vaillant that produces 3.40kW of heat for 560w of electricity in a similar sized house to mine.
I doubt the oversizing would be so much of an issue if my heat pump wasnât a Daikin, particularly a great big one pretending to be small!
Iâve reverted to normal now as the point seems to be proven (Basingstoke vs Ipswich) with the chart below. Compare before 10:30 = Basingstoke and after 10:30 âIpswich simulationâ
My COP drops a lot when the radiator output is limited (and my house gets cold)
So the main question now is how to get our Daikins to cycle most efficientlyâŠI doubt on this evidence that there is anything wrong with your unit⊠and you have adequate rad capacity to keep your house warm.
Decreasing the cycling frequency to give longer run times (and longer off times) would be my best guess at doing this. Hopefully experts reading this can suggest the best way.
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Thinking this through a bit more,
- You want a COP of around 5.0 with outside temp of 10c and know this is achievable with the Daikin unit (when it is running in equilibrium at a flow temp of 37c.)
- Your unit has a minimum compressor power of 920 w so that means you have to put 920 x 5 = 4.6kW out from your radiators as a minimum.
- Your house needs, say half of this - around 2.3kW to equilibrate at 21c internally when it is 10c outside. (it would equilibrate to 32c with the full 4.6kW)
- So you need to a) cycle 50% on and 50% off with the on and off periods as long as possible and bearable and b) get the radiator output to 4.6kW when the room temp is 21c.
Lengthening the cycle might be achieved by increasing the on-off hysteresis using the largest overshoot/hysteresis settings for both room temp and for Leaving water temp.
Increasing the rad output can be done by either increasing the rad sizes or increasing the Flow temp above 37c. With the latter solution there will be a trade off with COP but I suspect your optimum is above your current 37c setting. I would try it at say 45c to see what the COP looks like then, if it is no better than now then drop that to 40c.
I do hope this helps. One final check/question - is your unit set for RT control or Ext RT control? Field code C-07 = 2 or 1. It should be 2 as that uses the Madoka properly.
All the best.
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Hi Colin.
I have it set to use the Madoka controller, it is not set for a third party controller.
Last Friday I set the target room temperature to 30c and went a full +10c on my WD curve.
The flow temperature got up to 49c.
The COP was 3.17.
Our house needs less than 2.3kW to maintain 21c, when it is 10c outside, we need about 1.5kW.
My heat loss is about one third of the minimum output at a COP of 5, oops!
Even if my heat loss was the 7.3kW they calculated at 21c/-2.3c I would still only need 3.46kW at 21c/10c. This heat pump does not have the range of operation required for the houses it should be fitted in and that is because it is basically a de-rated 16kW heat pump.
I have tried it on my weather curve and then +2, +3, +6 and +10. None of it makes much difference.
When you looked at the run this morning it probably turned off early because the room temperature + the overshoot had been reached. The Madoka is currently set at 22c but the room temp is actually 22.9c
I will look at the other settings you suggest, the overshoots on room temp and lwt.
I suspect I am close to as good as I am going to get with everything as it is now.
Larger radiators will probably let the heat pump `breathâ more freely.
It will be a trade off between COP and overall energy consumption. I expect my best economic performance will not be at the best COP.
It should be better when colder and I can probably maintain a healthier COP at those times making periods like this less painful.
I am now 99% sure that the heat loss survey was carried out poorly, the heat loss was vastly overstated and that has lead to a heat pump being installed that is incapable of running at a low enough output to satisfy the heat demands of this house in moderately cold weather.
I will have to think about my best solution.
One problem I have is the location of the heat pump, asthetics are a concern amongst other things.
This is the smallest Altherma 3 monobloc available, some other Daikin is possibly an issue.
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One other thing I was told today by the engineer when I was explaining my problem with running on pure WC was that they donât offer a `bespokeâ setup for each home and that they install with the expectation that the Madoka thermostat is used.
I am bitterly disappointed with the whole thing to say the least.
One final thought on weather compensation. I donât use it, despite the expert advice because 1) my flow temp range is limited to 33 to 39c. Why? At 32 c the fan convectors do not operate and my rad output and so COP drops a lot and at a 40c setting which equates to -2 c outside my heat pump never reaches that flow temperature anyway because it takes longer to get there than the 35 mins it takes before needing defrosting. I can get the same optimization by using the modulation settingâŠa 36 âfixedâ flow temp with ± 3c. This will mean that the unit optimizes the temp between 33 and 39 depending on demandâŠand hence outside tempâŠand room tempâŠand everything else.
Your unit will use different logic but might still find modulation to be better. ie your minimum efficient flow temp is not the lowest temp possible because of the proven rad output limitations. So your minimum might be 37c and max 45c. You can achieve this with a fixed flow temp of 41c and modulation of ± 4c
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