Thanks @KnightPhoenix our setups look very similar - we have a room temp set of 20 and modulation of 8 + 38 and 30 degree WDC, but a schedule of 24/7. here is my MMI Export.
I have just tried limiting the pump to 60% the results are not apples for apples as the room temp was not 19.5 degrees at the start but around 20.5 (I will check again tonight and update) but I have noticed –
The l/min dropped from 27 to 16 l/min (as per the configuration limitation), then settled to the normal 7 l/min,
The DT was greater for longer, then settled,
the peak power draw was ~500W lower and ran for less time, I am sure this is because of the higher room temp starting point,
but the HP did not stop heating for 20 mins, trying to lose the heat from the loop…then startup again to settle
and I think the room heat up curve was lower, with a similar mean COP at 1 degree outside temps
I may look to drop ours further however we are currently waiting 4 more radiator swaps and I want to avoid a cold lounge (or further upsetting my very patient OH).
Interesting that it takes that long to stabilise after heating but a few people have noticed the 30-45 min spike on startup so maybe that would help.
Only thing I am a little wary of is limiting the pump speed as surely it would be better to have a higher flow and reduce the temperature further and allow modulation to push it up if needed?
Could the issue here be that on startup the pump aims for WDC until it has time to calculate return water temperature and see how much heat is lost before it starts to modulate (down or up)?. May explain some of the spikes on some systems.
Happy to be wrong (and who knows how and why Diakin seems to work this way) but I think a lot of this is going to be trial and error as even the installer reference guide is not great or clear at times.
Just an update, I am on a 70% pump limit, its been tricky to see a trend and change with -4 outside temps, the power demand peak appears to be the same as unlimited, but the delta T during startup is a little higher 5-7 ( 7-9 with 60%) rather than 3-5 on unlimited, the result is a lower heat up time and I think a greater COP.
I will leave it for a few days as its due to heat up over the next few days and my aim is to have a longer and slower heat up cycle during milder outside temps increasing the COP, rather than the DT narrowing and stopping the HP then starting up again ~20 mins later after the system tries to lose the heat then initiates a second heat up and peak of electricity before settling in to a steady state.
Its really odd as all my research infers you must have a high flow rate to lower the LWT, maybe in my situation, we have little resistance as a result of a full re-pipe 28 – 22 – 15 with oversized radiators, I will follow the data and take advice from others
Eventually you will reach a lwt that cannot give the dT required and then a higher flow rate is necessary to get the heat.
If the radiators can maintain a requested dT at a low flow temperature and need a low flow rate to do it then that is great…Generally I would expect that most homes won’t get a high dT at really low flow temperatures and therefore need a higher flow rate to get the heat.
As an example you could flow 10lpm at a dT of 8c or 20lpm at a dT of 4c, the heat produced would be the same, one way may use more electricity than the other due to pump speed and flow temperature required.
Just experiment until you find the best outcome.
You may find that tighter dT at a higher flow rate uses less electricity as the water comes back to the heat pump closer to the lwt but maybe not as it needs to heat more of it by less.
My own approach is the lowest possible flow temperature at the biggest dT and lowest flow rate, should produce the most heat for the least electricity. Less flow temperature also seems to minimise defrosts.
There is no one correct answer, heat produced is just a product of the loss of temperature of how much water. There is more than one way to get the same result.
Every home will be different and how low you can go depends on many factors.
I have gone back to an unlimited pump setting last night, I think it’s best for us to just let the HP do its thing, I did note the LWT was higher when throttled so I guess using more energy, also the heat up times look slower with an unlimited pump setting., at was our main goal
I think the Daikin algorithm (modulation) needs to influence and change the pump speed quicker depending on the outside temps so it does not overshoot the targeted room temp, again I am chasing diminishing returns, our space heating COP was over 3.5 at -4 outside, and a cop over 4.5 when around 2 outside at our off peak electric rate of 7p per unit it’s all good.
BTW have Daikin returned to tweak or dial in for settings?
last 48hr, 24hr with 70% pump limit then 24hr unlimited.
Hi @tiger_cook and @matt-drummer interesting discussion on configuration. I have a new Daikin 8kW EDLA08E2V3 installed by Octopus - same as Neil and just now trying to optimise the efficiency. Interesting links to videos although I don’t seem to have anywhere near as many controls on my MMI as the one in the video. Just noting that @tiger_cook said in the original post that he’d set up the ESPAltherma to monitor COP - just wondering what this was as I would really like to be able to monitor this and make adjustments?
For access to all of the settings in the MMI go to user profile and use the code 5678. This will unlock the installer menus and extra options.
The installer reference guide will explain all of these and is available from Daikin’s website.
When finished go back to user profile and set 1234 for advanced user.
Also make a note of all changes so you can revert them back if it goes wrong or in the installers menu page use the export MMI settings option (you will need a usb stick plugged into the controller but can export and save / share all settings).
Hi, happy to help if I can, here is the MMI guide to help with the parameters and menu tree, D series MMi.pdf (5.2 MB)
1st start with the WDC and then tweak the modulation, it goes without saying make one change and see the results, its tricky in the UK as it all depends on the outside temps, as from one day to the next could swing 10 degrees, and may take a few weeks to settle on a good profile for your house.
If you are using Madoka for thermostat control, rather than leaving water temp only, then I suggest you go into the Madoka settings and reduce the brightness of the screen and the blue ring light that indicates the heating is running.
I reckon the LEDs affect the reported temperature by at least 1C compared to local ambient. I’ve configured a -1C offset in the MMI for this.
In the case of the blue ring light, I was seeing a very quick drop of -0.5C as soon as soon the heating switched off. It played havoc with the thermostat control when I disabled modulation.
I’ve seen more consistent readings since changing these settings. I’ve turned it down until the values are just visible in daylight. There is also a “hotel mode” that switches off the backlight and blue light. I haven’t enabled that as I do like to be able to see the current temperature
Hi @squarepeg77 Jonathan, this is an excellent call, its incredible the Madoka was given a design award, negating the function of the unit….
I have made the changes, all lowest brightness on the Madoka, its even resulted in longer cycles and a continuous COP around 5 (outside 5 – 8), our HP has not stopped (ie reached room set temp) since it started yesterday, we have a steady hovering 21-degree room temp (set to 20) knowing it will stop the HP at 21.5…its really improved the modulation effect.
I did see an article of someone cutting a small hole in the bottom of the Madoka to enable the sensor to be exposed outside the case, but I cannot find it again to share.
@squarepeg77 you know what, I thought it was just mine that did this…its a terrible issue given its’ function and why I can’t use it.
I had discovered this about a year ago, and turned the blue light it down to lowest setting and it is still really obvious something is not right as minutes after heating switched on, the indoor temp rises before any real heat delivered from the heating system!
I’d quite like to go back to Madoka control, as I’m a little uneasy relying on cloud functionality to turn the heating on and off. (I’m now using leaving water temp with Home Assistant temperature control.)
However I really need 0.5C control in the Madoka schedule, not 1C. It’s silly that you can offset by 0.5C, but not set a schedule with a 17.5C target temperature.
BTW I have turned down all the brightness on the madoka, LED and backlight etc with an offset of -0.5 to give a really accurate measurement, I have other sensors that confirm this is good!
I have picked up a little config gem that I think works thanks @KnightPhoenix, after just one change setting the DT to 3 - after one heat cycle with similar outside temps the COP appears smoother and higher -
For my 9kW, I’ve found that lowering dT from 5C to 4C enables the flow rate to get above the minimum 10.7l/min more often.
I think (speculate!) this then enables the heat pump to modulate heat output by changing flow rate instead of having to vary compressor power, because flow rate is at the floor.
I’ve been running with dT 5C for a while, but your post reminded me to go back to 4C! I don’t think I’d tolerate 3C, that would probably give more noticeable noise from some of our lock shields.
It played havoc with the thermostat control when I disabled modulation.
