No problem - my back up heater seems to kick in sometimes for 5 mins only. Sometimes when the HP fires up for the first time after being off all night.
It must be a system thing because I have set it to only come on below -6c
This morning for example…
Modulation - there are two field code settings, one just switches it on and off and the other sets the number of degrees. So if you switched it off the degrees number will have stayed at 10
I have ordered the rest of the new radiators, the K3s.
Hopefully that will make things better.
I have also ordered some Speed Comfort fans to try on a couple of radiators.
I should have them tomorrow or the day after so it will be interesting to see what difference they make to the rooms I intend to use them in and if there is any improvement in the heat pump performance.
The fans can be used on the new radiators too as one of them is in our conservatory, any extra heat there is ok.
EDIT 14/11/2023: subsequently found another filter/strainer on the return (correct) that I initially thought was a standard lever shut off valve. It was way worse and jam packed with black debris.
See post below:
@matt-drummer & others
Since I installed ESPAltherma, I can now see flow rates, which seem(ed) stuck around 24L/M - yet I seem to remember soon after installation (September ‘22) seeing just over 30L/M……and have seen other similar units with higher flow rates
I had to ring Octopus in October re: annual servicing, and the earliest they could do was start of Jan ‘24 
So decided to investigate and came across two pretty easy serviceable elements: filter/strainer that when particles accumulate, flow is restricted, and magnetic filter.
Note: Octopus did not power flush/clean the existing system prior to connecting heat pump. (Controversial I now know…)
I used these resources amongst others:
Service Manual for Daikin Altherma 3M
Service Manual altherma_3_m.pdf (7.1 MB)
Mine was filled pretty badly with black gunk (but maybe not as badly as I expected and forgot to photo it prior to cleaning out.
I’ve gone from 24L/M to ~30L/M (yay! But wait til the end…)
Also worth checking two other things:
Is the filter on the correct connection (should be on the return to the unit to protect the outdoor unit - mine below is on the bloody flow/output from the unit!!!
This is the printed supplied documentation that came with the revision of the physical unit we had installed in September ‘22: you can clearly see it matches our unit (quelle surprise), but that it’s fitted wrong way round (as in on the flow rather than return…:
The only minor plus point is the strainer/filter is at least the correct orientation to catch stuff before it heads back into the house….
This is from a PDF version I found that thought was the same, but Daikin have clearly swapped positions of flow/return, and Octopus were (are?!) running off maybe a previous revision/iteration:
Lastly, the Fernox TF1 that Octopus seems to install as standard was also easy to clean out/check, and again not great but not terrible:
Interesting! There is a setting that controls the maximum pump speed - is yours on 100%? Mine’s set to 6, which is obviously less, and the MMI is showing maybe 26lpm at times, more at others. I am about to install the eSPAltherma, so that will be worthwhile.
Hi @John,
I assume it’s this? If so, I have actually tried a number settings and at present back to no limits - to be clear, the thing that sorted the max flow rate was cleaning the strainer/filter (that is stupidly on the flow from the outside unit, when it should be on the return just before it goes in)
Unit runs at a whopping 300watts now when the compressor isn’t running and flow is ~30L/M!
Do you have a photos of your pump speed “6” setting?
What action against Octopus would others take on the Strainer/filter installed on the flow rather than return?
Ask Octopus to fit correctly on the return and replace the PHE in the unit as likely filled with debris? Or is the second point too far?
MCS?
This has definitely had an impact on flow rates - that important and on-topic has only really been shown via OpenEnergyMonitor
Hi Stephen,
I have just got home from work and checked mine. I was sure it was fitted on the return but wanted to be sure and it is.
I would ask them to install yours correctly.
I don’t know the impact of incorrect installation but I would imagine that when the filter is installed correctly any debris will make its way to the filter.
Whether any damage has been caused, who knows.
I was wrong, Octopus did put a strainer/filter on the return correctly as well as the flow out to the heating system.
I hadn’t appreciated there might be two, and the second on the return looked like a standard isolation valve.
Unfortunately it was jam packed with debris - literally so bad whilst still in the valve, I couldn’t get a finger in and had to dislodge the sediment which promptly fell onto the floor. No idea how it was still working.
I then pulled out the strainer/filter on the return, and this is what was left:
Up to a max of ~34L/m now - that’s up ~10L/m (~40%) from yesterday after cleaning out both strainers/filters (the other way of looking at it, it was down to ~70% of a near clean system at my house):
My system clearly needed flushing, and still does.
Until then I’ll keep cleaning these both out and keep an eye on flow rates which if monitored over time, can show how healthy things are.
I will update/edit my post above to reflect the other strainer/filter.
Worth checking!
I see that @Zarch noted this (and strangely the exact same % drop in flow rate!) on his annual service a couple months back, so really is a thing and I guess maybe more focus placed on relative flow rates vs new/clean system, as it could be impactful and very very easy to clean out.
https://twitter.com/Zarch1972/status/1701963948147286116
Servicing works!! Don't scrimp on this!!
— Mick Wall (@Zarch1972) September 13, 2023
I never realised the role the strainer played in the whole system.
DHW run before cleaning: 840 litres/hour
DHW run after cleaning: 1190 litres/hour
And there wasn't a great amount of crap in there really.#checkyourstrainers… pic.twitter.com/YyT4KP74rP
Wow!!
I’d be having a serious go at the installer!
Ooo that’s an annoying change to catch out installers!
[edit after seeing your second post]
A strainer on the flow FROM the heat pump with dirt in it can ONLY have dirt in it if there was dirt running through the plate.
There being two strainers is a little suspect. Did the installer realist their mistake AFTER having filled the plate with muck?
@marko Octopus haven’t been back since the install in September’22 (annual service booked for Jan ‘24)
No idea why there are two: that’s what caught me out as I had insulated them and only uncovered first one fully. It was only my curiosity and to make sure I got my facts straight that made me look again before I called Octopus to get them to sort it out.
I guess the second strainer will have stopped some debris making its way into the Mixergy PHE! (Trying to put a positive spin on this)
I’m adding this info to this thread as it’s related to performance, and I’ve really only spotted the issue once OpenEnergyMonitor data can be seen visually: pump running max all the time and only reaching 70% - maybe @matt-drummer has debris build up in his strainers?
Maybe this will help others out, and re-enforce the importance to have a flush out prior to new unit - and also regular (at least annually) clean out of strainers / filters!
Hi Stephen,
I think I only have one filter outside but I need to check when it is not raining.
The one I can see easily is on the return and is identical to the one you showed in your photograph fitted on your flow.
My filter(s) outside and the magnetic filter indoors were cleaned three weeks after the install.
The one(s) outside were full of installation debris according to the `engineer’ and the magnetic filter was very clean, nothing there of any note and the water was clear.
The water from the magnetic filter was also clear when I drained it a month or so ago to fit my OEM system.
It has been in my mind though that filters may be adding to my issues so it is well worth checking.
My radiators all all fairly new as was my gas boiler and I would be surprised to see what you found, but I don’t really know so will check.
I’m glad you have found something and at least the return to the heat pump was protected.
Maybe it is concerning that the flow filter was badly clogged?
I think this thread has evolved in to a how to work out what Octopus did wrong with your Daikin installation and how to make the best of it!
I have said it a few times though, we would never know without this sort of monitoring and perhaps more importantly, help from the great people here.
I’m not sure the Fernox TF1 filter is that great - not very much when I emptied that.
Sorry about that!
Spot on - seeing your issues, spurred me onto setup ESPAltherma, and while accuracy of readings may not be “up there” with your billing grade setup, it is certainly worth it as relative values seem to be great.
There is a bunch of other data such as compresseor and water pump speeds that provide additional context to things like flow rate (e.g. max pump speed + lower than normal flow rate = a problem)
Hi Stephen,
I think it’s great when threads evolve, no criticism and no need to apologise.
It will be a very useful resource for all sorts of problems although a bit of a long read!
Thanks for the pix and info. I have mine connected and it is sending data, which is excellent. I added the “{0x21,4,101,2,-1,“Voltage (N-phase) (V)”}, // Added from list_labels.csv as an experiment” to collect the additional voltage data from the inverter to the ModBus definitions file, and it seems to work.
However, when I put the cover back on, the M5Stick loses wifi signal because it’s basically in a Faraday cage. You can see the low signal just before it decides to go offline in the last MQTT message. So I’m wondering what sort of wifi signal you’re getting with it in the box, and if you had to move it around - my Dupont wires are a bit short, I can get longer ones obviously. Meanwhile, since I can’t leave the cover off, I’ll be without quality data.
{“Operation Mode”:“Heating”,"… “M5VIN”:“4.37V”,… WifiRSSI":“-83dBm”,“FreeMem”:“187184”}**
Done. Waiting 29544 ms…
Offline
Lift cover off…
Online
Querying register 0x10…
I’m afraid I had to add another Google WiFi mesh puck on the other side of the wall - luckily I had already cat5e cabled the area 4-5 years ago back to the other points for the Mixergy tank connection, so was easy for me.
Am trying to think what to do longer term however.
This is a huge thread. Is there a summary of what would need checking post Octopus Daikin install, should I decide to take them up on their very reasonable quote? Or shall I allocate an hours reading? 
I see you fixed your efficiency though!
Hi Peter,
I think you need to be more focussed on pre install rather than post install.
The first thing is the survey. Check the heat loss calculation and make sure of your radiator sizes to ensure that you will be able to run at low flow temperatures if that is what you desire.
I would also check that the heat pump is suitable for your needs both in terms of meeting your heating requirements at the lowest temperatures you expect to endure (which is probably most important) but also where your home spends most of its time.
A heat pump that is too big and that won’t modulate down to a level that suits your home most of the time is difficult to deal with.
I can’t recommend strongly enough that you get monitoring systems such as OEM fitted, you will struggle to know what is going on and optimise performance without it.
It’s all a compromise though, a heat pump that is too small will leave you cold and that is probably the worst outcome. One that is massively too big will cost you money so really one that is a bit too big but runs at a modeartely low level is the optimum solution as far as I am concerned.
My efficiency is not fixed yet but nearly, watch this space! 
My Moderator’s account says it’s been a long, long time since we last saw you. 
Good idea 
Seriously though, we really need a good technical writer with knowledge of heat pumps to write a section in ‘Learn’ distilling all the excellent information that’s in danger of being buried in the forum.
I’m reasonably certain @glyn.hudson & @TrystanLea in particular and a lot of prospective heat pump users would appreciate it.
