How to reduce frequency of defrosts on Daikin Altherma?

Chris_Hill · 2025-01-10T22:32:45.187Z

i found the pump limitation setting , it was already set to 80% possible by me when i was previously playing with setting , ive now reduced this to 60%

divenal · 2025-01-10T22:38:15.173Z

Chris_Hill:

I think i am going to move to pure weather compensation without modoka influence ,
i noticed since changing my latest setting that the system is reacting to room temp , ie its trying to meet room target temp before anything else

Ah - I hadn’t twigged that there was much Madoka influence, other than the level of modulation. I wonder if that’s the extra factor I was missing in my ramblings above: if the room temp is below target, then it selects high P and F, because it needs to get more energy into the house.

dmajwool · 2025-01-10T22:40:27.832Z

Chris_Hill:

do you remember where the setting is for limiting the pump speed ??

Hi Chris,
The pump speed limitation setting is in the Space Heating/Cooling section.
Breadcrumb 4.7.

Chris_Hill · 2025-01-10T22:45:12.493Z

yep ive now reduced it to the minimum setting of 60% , hopefully i wont get the error message which can appear according to the question mark information

made the changes at 22:30 and so far it looks like its made a immediate effect on the patterns

https://emoncms.org/app/view?name=My%20HeatPump&readkey=1da9e37af3d5ac9669792233ea85675c

but i wonder if the modoka is still influencing it

Chris_Hill · 2025-01-11T08:14:06.096Z

ive now set the mmi on to ( control to leaving water ) or pure weather comp which has removed the modoka from the control its even disappeared from the mmi home screen
through the night my dT once the system had settled went up to 10, hopefully the system will settle better with new setting over the next few hours

Chris_Hill · 2025-01-11T10:27:44.682Z

some good news after moving to pure weather comp , efficiency is going up power is starting to look like its going down now things are up to temp and pump speed is lowering , hopefully this will increase the time between defrost cycles
@matt-drummer thanks for spending the time explaining what you have done with your system , this has certainly got me to where i am a lot quicker

the only other thing that might help is reducing the target dT lower from 12 , but at the moment im leavening this at 12

the modoka does interfere far to much

Chris_Hill · 2025-01-12T14:05:30.080Z

@matt-drummer are you reducing your flow temps to reduce the defrost cycling ? just noticed you flow temps have jumped up as it got warmer or is this to raise the house temps before defrost starts ? ( just before your hot water cycle )

matt-drummer · 2025-01-12T14:09:53.666Z

Hi Chris,

No, it’s just Daikin.

I haven’t changed anything.

It does it all by itself.

Flow has been set at 30c for the last couple of days.

Part of my frustration with it, it generally does what it likes.

I have lost interest, quite a long time ago actually, and just let it get on with it and live with the results.

Not great, but I think we all know what I think of Daikin heat pumps.

Chris_Hill · 2025-01-12T14:16:19.175Z

so the software made the jump , do you think this is in prep for the hot water cycle , it would be good if Dakin explained somewhere what there strategy was , if their is one

matt-drummer · 2025-01-12T14:21:55.118Z

No, it can’t be.

I turned off the hot water yesterday as we were Ok without it.

I promised my wife I would do it today though.

But I forgot to turn it back on so missed the scheduled time of 13.00

So I know it is nothing to do with DHW.

It was actually 2c over the set amount at night, reduced a bit as it got colder, and then crept up more. And then after the last defrost jumped up a bit more.

I don’t know why, and I don’t care, it is just what it does.

My 9kW was actually much better at holding the set flow temperature, but this one is awful, it is always missing it or even worse, hunting up and down.

I am sure it is not as well made as the bigger units. It was my fear about swapping.

I just want a heat pump that runs at a fixed flow rate and the temperature I asked it to.

Tempted to go down the Stiebel Eltron shop!!!

Chris_Hill · 2025-01-12T14:26:03.872Z

at the moment mine seems to be following the weather curve i have set , but will keep my eye on for any strange behaviours ( do you have a minimum and maximum room temp setup ) sorry to ask as it sounds like you have had enough of it

i ahve a maximum of 23 set but not sure if this will kick in now i a\m on Pure weather, and think i have a minimum setup of 18

matt-drummer · 2025-01-12T14:38:27.134Z

I have no room temperature control, other than me

I took out a three year old Vaillant gas boiler to do this.

I didn’t do it because I needed to, I did it because I wanted to experience something new and enjoy the journey.

I haven’t enjoyed this at all.

Well, maybe I have enjoyed dealing with the problems and extracting as much from this as I can.

But I have done something I never do, and bought the cheapest.

I normally do the opposite, everything I ever buy is the best and most expensive, cars, I have to have top of the range, musical instruments, the same.

But this, I should have waited, but it is one of my other failings, too impatient!

So, because Octopus were my only option at the time, I got lumbered with Daikin.

I should have known better.

I hate the thing and it will have to go.

Chris_Hill · 2025-01-12T14:41:31.526Z

i am not sure its room temperature control this is a setting in the mmi, but it must be taking the temp from the modoka , if it kicks in during pure weather comp , i will have to wait and see if it kicks in

matt-drummer · 2025-01-12T14:44:00.852Z

My maximum room temperature on my MMI is set at 30c

John · 2025-01-12T15:07:17.735Z

If you’re on pure WComp, then it doesn’t care what temp the house is. That’s not the HP’s concern! It’s the easiest way to get the curve dialled when it’s cold, and there isn’t solar gain. The you could switch back to Madoka+WC in the knowledge that it’s about right apart from external inputs like solar gain.

divenal · 2025-01-12T18:20:42.601Z

I’ve now made the same change, and it does seem a lot more stable, and after a defrost is able to (reasonably quickly) get back to a lower-power state. I’m stilling using a DT of 4, but I notice that straight after a defrost, it jacks LWT directly up to the configured temperature, so that it’s heating the cold water by say 8 degrees, rather than slowly ramping it up by, say, 5 degrees and allowing the returning water to gradually heat up. So I’m not really sure how much difference using a larger DT would make.

But for my system, using DT of 4 still seems to make sense since that seems to be expected delta once the system has reached equilibrium. When I had it at 5 (while still using Madoka control) it seemed to want to keep elevating LWT each time the RWT got up to (LWT-4). But I’d need to go back and re-test that having removed the Madoka input control.

Chris_Hill · 2025-01-12T18:22:49.059Z

have you got a link to your system on heat pump monitor so i can follow to see if we can see any differences that the dT is causing

divenal · 2025-01-12T18:34:45.540Z

Unfortunately not - don’t have any proper monitoring. I’m logging LWT via API every 10 mins, and the energy consumption from CT clamp from Zappi. Things like flow rate and return temperature I’m having to eyeball from the MMI.

Something I want to investigate is whether I can interrogate system parameters over bluetooth via the Madoka. But haven’t got very far with that yet. (I know there’s a hardware option that can be wired into the P1P2 bus, as well as ESPAltherma.)

2025-01-12--13:06: power=1572 outdoor= 2 room=18.7 / 20.0 hw=41  lwt=40 (offs=1)
2025-01-12--13:16: power=1840 outdoor= 2 room=18.7 / 20.0 hw=41  lwt=39 (offs=1)
2025-01-12--13:26: power= 302 outdoor= 2 room=18.7 / 20.0 hw=41  lwt=39 (offs=1)
2025-01-12--13:36: power=2550 outdoor= 2 room=18.7 / 20.0 hw=41  lwt=40 (offs=1)
2025-01-12--13:46: power=1748 outdoor= 3 room=18.7 / 20.0 hw=41  lwt=42 (offs=2)
2025-01-12--13:56: power=1618 outdoor= 3 room=18.7 / 20.0 hw=41  lwt=42 (offs=2)
2025-01-12--14:06: power=1624 outdoor= 2 room=18.7 / 20.0 hw=41  lwt=42 (offs=2)
2025-01-12--14:16: power=1422 outdoor= 2 room=18.8 / 20.0 hw=41  lwt=41 (offs=2)
2025-01-12--14:26: power=1403 outdoor= 2 room=18.8 / 20.0 hw=41  lwt=41 (offs=2)
2025-01-12--14:36: power=1392 outdoor= 3 room=18.8 / 20.0 hw=41  lwt=41 (offs=2)
2025-01-12--14:46: power=1375 outdoor= 3 room=18.8 / 20.0 hw=41  lwt=40 (offs=2)
2025-01-12--14:56: power=2040 outdoor= 3 room=18.8 / 20.0 hw=41  lwt=40 (offs=2)
2025-01-12--15:06: power=2503 outdoor= 2 room=18.8 / 20.0 hw=41  lwt=31 (offs=2)
2025-01-12--15:16: power=2822 outdoor= 3 room=18.7 / 20.0 hw=41  lwt=42 (offs=2)
2025-01-12--15:26: power=1764 outdoor= 3 room=18.7 / 20.0 hw=41  lwt=42 (offs=2)
2025-01-12--15:36: power=1420 outdoor= 3 room=18.8 / 20.0 hw=41  lwt=42 (offs=2)
2025-01-12--15:46: power=1416 outdoor= 2 room=18.9 / 20.0 hw=41  lwt=41 (offs=3)
2025-01-12--15:56: power=1616 outdoor= 2 room=18.9 / 20.0 hw=41  lwt=41 (offs=3)
2025-01-12--16:06: power=1622 outdoor= 3 room=18.9 / 20.0 hw=41  lwt=42 (offs=3)
2025-01-12--16:16: power=1630 outdoor= 3 room=18.9 / 20.0 hw=41  lwt=42 (offs=3)
2025-01-12--16:26: power=1630 outdoor= 3 room=18.9 / 20.0 hw=41  lwt=42 (offs=3)
2025-01-12--16:36: power=1634 outdoor= 2 room=18.9 / 20.0 hw=41  lwt=42 (offs=3)
2025-01-12--16:46: power=1634 outdoor= 2 room=19.0 / 20.0 hw=41  lwt=42 (offs=3)
2025-01-12--16:56: power=1631 outdoor= 2 room=19.0 / 20.0 hw=41  lwt=42 (offs=3)
2025-01-12--17:06: power= 604 outdoor= 2 room=19.0 / 20.0 hw=41  lwt=41 (offs=3)
2025-01-12--17:16: power=2362 outdoor= 3 room=19.0 / 20.0 hw=41  lwt=38 (offs=3)
2025-01-12--17:26: power=2663 outdoor= 3 room=19.0 / 20.0 hw=41  lwt=38 (offs=3)
2025-01-12--17:36: power=1804 outdoor= 2 room=19.0 / 20.0 hw=41  lwt=44 (offs=3)
2025-01-12--17:46: power=1458 outdoor= 3 room=19.1 / 20.0 hw=40  lwt=42 (offs=3)
2025-01-12--17:56: power=1457 outdoor= 3 room=19.1 / 20.0 hw=40  lwt=42 (offs=3)
2025-01-12--18:06: power=1452 outdoor= 3 room=19.1 / 20.0 hw=40  lwt=42 (offs=3)
2025-01-12--18:16: power=1634 outdoor= 3 room=19.1 / 20.0 hw=40  lwt=42 (offs=3)

(I’ve bumped LWT a bit since house has got a bit cold.) Looks like defrosting cycles at 15:06 and 17:06 ?

Not sure why power dropped at 13:26 - perhaps just LWT overshoot? I need to increase overshoot so that it tolerates requested LWT dropping when outside temperature rises, for example.

Oh, no, looking at the more frequent power logs on my zappi logging, probably was also a defrost.

John · 2025-01-12T18:42:24.681Z

Madoka BT - don’t waste your time, you can only update firmware from Onecta app!

Chris_Hill · 2025-01-12T18:43:11.580Z

which can take hours to update on certain sensors