Something has gone quite wrong with my 8kW Daikin today!

tiger_cook · 2024-12-06T12:01:46.924Z

Chris_Hill:

Does it shut off completely ??

I think so, I am sure others will chime in if i am wrong.

Chris_Hill · 2024-12-07T09:54:08.785Z

another thought , octopus left my heating circuit at 1.5 bar and i have been making sure it stays around 1.5 bar , i have just been looking through the daikin stuff and 1.5 bar is the minimum pressure so i am going to increase mine to 1.8 bar and see if it makes any difference

Mld · 2024-12-07T14:05:02.191Z

My installer did say he like to leave it closer to but not more than 2 but didn’t say why and I didn’t question it at the time.

meatballs · 2024-12-07T20:33:45.217Z

@matt-drummer with the significant radiator changes made to the system did you also look at the pipework calcs?

matt-drummer · 2024-12-07T20:47:01.443Z

Hi Ben,

No, I just fitted much larger radiators.

Why do you ask?

Timbones · 2024-12-10T13:15:54.278Z

36 posts were split to a new topic: Heating power calculation from ESPAltherma data

tiger_cook · 2024-12-09T08:47:25.361Z

meatballs:

@matt-drummer with the significant radiator changes made to the system did you also look at the pipework calcs?

Hi @meatballs, is this what you are thinking?

image1609×843 156 KB

tiger_cook · 2024-12-09T08:50:33.187Z

tiger_cook:

Like all trial-and-error methodology, make one change and see the result.

The immediate result is now on the MMI screen I can see the LWT at 35 not 31, can your system get up-to 24 L/min on an air purge test (I think you also have limited the pump to 60%)? If not, could this be limiting the unit not changing the LWT, on your manual input, just like my experience?

I will also report back when the heating switches back on with the results, the house is up to temp now.

Monday update, yes, opening the radiators 100% downstairs (sized correctly to the heat loss) helped me get a higher more accurate LWT, hope this helps others?

matt-drummer · 2024-12-09T09:40:28.833Z

Hi Neil,

My flow rate is only affected at the start of a space heating cycle in reality.

All my 60% limitation does is stop the amount of heat produced in the first 20 minutes or so and this is only of use when running low flow temperatures at higher outdoor temperatures.

Otherwise I don’t need the limitation, and I probably don’t need it at any time now as I have worked out that really low flow temperatures are a no go.

So, even if I removed the pump speed limitation I would still be running on radiators at a dT of 10c with the flow rate firmly fixed on the bottom.

Unfortunately, although Daikin say that higher flow rates result in higher efficiency, their heat pump cannot run at a consistent higher flow rate, instead it constantly changes from one extreme to another trying to get control of the return temperature.

I have found this to be less efficient.

With regard to pipe work and radiator sizes, changing the radiators has not changed the heat loss or the amount of heat I want the heat pump to deliver, I am just able to do it at a lower flow temperature with bigger radiators.

I am pretty sure that even the worst pipe work can deliver a maximum of 4kW at 7lpm.

squarepeg77 · 2024-12-09T10:44:53.866Z

Hi @alibloke, I was told the firmware was supposed to improve the responsiveness of the expansion valve. That’s all I know and I can’t say I noticed any before/after changes from my monitoring of it using ESPAltherma.

I think the big improvement for my system was getting the tape heaters disabled. Before, my system would not deliver a reliable delta-T to my house as it was tape heating the water returning to the heat pump!

tiger_cook · 2024-12-11T12:03:44.779Z

Chris_Hill:

This is a long shot , I did see some strange behaviour once , after a change I made to the weather curve
. This continued for a few hours and after that I removed the mmi causing it to shutdown ( pull just at the top ) after the reboot things went back to normal , might be worth a go
Chris

Hi @Chris_Hill you may be onto something, I made a change yesterday morning that caused a reboot – nice steady LWT and constant 500w draw, ~12hrs later back to fluctuating power and LWT, this morning I initiated a short on/off via onecta and its back to a nice steady LWT and constant 500w draw. This could be good evidence for a Daikin support ticket?

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Chris_Hill · 2024-12-11T16:26:27.081Z

the only down side to doing this , is the hot water cycle starts after the restart if your water in tank is cool enough , did you just switch on/off the Central Heating in the app ( does this start the hot water cycle ??

tiger_cook · 2024-12-11T16:39:48.833Z

Yes, I just turned off the space/central heating via the API in HA (same as in the app), no DHW heat, just the mini peak before settling down.

Chris_Hill · 2024-12-11T16:58:10.684Z

makes you wonder if the long runs are over whelming the refrigerant over the long runs

or the inverter is running at such a low frequency (Hz) compressor is struggling and if this is the case the compressor is going to have a very life span, ideally the frequency should be running the compressor between 40-70Hz once you start running outside of this the inverter and compressor will have reduced life

Robert.Wall · 2024-12-12T21:01:26.353Z

12 posts were split to a new topic: ESPAltherma / ESP32 power supply problems

matt-drummer · 2024-12-12T17:34:01.078Z

So, this thread has gone into areas outside my original problem, which is fine, and has been useful.

My original problem has not reared its head for some time with me which is good news.

My heat pump is in a fairly exposed location, against one wall of the house but wide open at the sides and the front.

Now that the wind has died down it is running very steadily.

So maybe air flow (wind in this case) is an issue. It has certainly made the heat pump less efficient by the looks of it as now it is calm it is running really well even though the headline outside temperature is no higher.

I feel that it is all rather sensitive to the weather, wind (turbulance?), wind chill, and higher outdoor temperatures coupled with low flow temperatures.

I feel happier that I have some idea of what is going on and what to treat as normal behaviour.

dmajwool · 2024-12-12T22:23:40.690Z

matt-drummer:

My original problem has not reared its head for some time with me which is good news.

I’m not so fortunate @matt-drummer. Mine has been erroring twice a day like this at 8pm today:

Screenshot 2024-12-12 2215041114×583 87.4 KB

At midnight last night I saw it starting to error and switched off heating using Onecta and immediately re-enabled heating. When the pump started up again, it was not in the error state:

Screenshot 2024-12-12 1040241107×583 88.4 KB

I’ve started a discussion with Octopus aftercare engineers about this and will report back when that conversation concludes.

Cheers, David.

matt-drummer · 2024-12-16T19:11:36.130Z

So, the first time I have seen it on anything other than an 8kW although I’m not sure what this really is as the flow temperature increases, so maybe not the same issue?

This is @Chris_Hill 6kW in space heating and the run came to an end, so either @Chris_Hill shut it down or it did it itself?

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Chris_Hill · 2024-12-17T12:22:38.202Z

what day was this and what are you pacifically looking at

matt-drummer · 2024-12-17T12:26:50.298Z

Hi Chris,

It was yesterday.

It looks odd but maybe not the same issue as I thought me and others have experienced.

Large increase in electricity and not enough heat for the consumption (shown by the plummeting COP)