OK, good, I look forward to hearing the results after the replacement.
I am surprised you have any heating at all if the abv is letting 29lpm through when it is closed.
Very true , but this was under test conditions, not sure what this means in real life , this may explain my low DT
I hope this works to sort out rad , if not floor boards will need to be lifted and rad re-piped will also see if this effects any of my monitoring readings
I Will update after swopout
I am not really sure what the problem is?
Is your house not warm enough?
Or is it just the dT that bothers you?
The dT is lower than you have asked for because the system cannot get rid of the heat produced at the lowest possible flow rate.
Whether that is because of a faulty abv, I donāt know.
I am pretty sure that there is no way 29lpm is flowing through your abv when it is shut, faulty or not, test or not.
If that was the case, I suspect your heat pump wouldnāt even run.
Your data looks completely normal, all of these behave the same way.
How much radiator capacity do you have?
kW at dT 50c
Weāve seen these kinds of compressor oscillations on Samsung heatpumps too: Samsung HT Quiet R32 8KW / EmonCMS - COP vs simulated COP and zigzag pattern
Oh, thatās interestingā¦ I have a suspicion that my abv may be leaking. If I fully open it, I can hear water rushing through it, but canāt really tell whether itās allowing water through when itās back where it was set. But (as I described in another thread), return temperature after the abv is consistently higher than before it. (But nowhere close to 29lpm - based on temperature change, perhaps around 4.)
But not quite sure how you can infer leaking valve from thatā¦ If pump has enough pressure to push 29lpm through the heating circuit, then youād get that rate whichever path the water was taking.
Hi Matt, what would be the effect of setting dT to max. and min. values ? Especially with my T21 rads which are designed to dT of 10c I guess. Now I have set it to default dT=5. Max. I can set is 8c, min. is 2c. I suspect that with dT=8c the flow rate should decrease much faster, eventually reaching the min flow rate sooner. I found that after start or defrost or dhw heating it always statrts at 100%. Then it starts to lower the percentage down but only very slowly. The inverter pump does nothing with flow until itās lower than 75%. Then the flow decrease slowly until 25%. So wonder if it would help to set 8 for my rads or if 5 is enough.
Hi
Rad total at DT50 is 16Kw
Original question was around the cycling of the flow T , and electric between two numbers , with very low flow rate, which looks like a common standard operation for some pumps.
This thread then branched into if the abv could be effecting the operation of the pump as it looks like my valve is not correct , I do agree that the reported flow reported dos not sound correct. However I can confirm pipe temperature after valve is higher than my central heating return pipe before it gos into the volume miser , not sure what this acutely means in reality
As the valve should be changed next week I will see how/if this was effecting the system
I found it best to just experiment Michal.
I would think that a bigger requested dT would change how the pump operates and aim to get a lower return temperature.
But in most cases, a lower dT is better for getting heat out of the radiators, a higher mean flow temperature through the radiators.
Give it a go.
I only set a high dT to keep the circulation pump at a fixed flow rate.
I am not sure if its too soon, but has FW 7.7.0 fixed the micro flutters? at 5 degrees outside the DT and power is really stableā¦
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Thanks Nigel. Iām still on FW 7.6 and my micro flutters are not continuous. Iām seeing some correlation between the flutters occurring when ext ambient temp changes.
is there a instruction somewhere to update to v7.7.0
Open the onecta app and you will see an update
no update yet , maybe they are not sending it out all at once
It hasnāt fixed it for me, flutters are still there on 7.7.0
update has come through this evening , currently updating now
I too am seeing a lot of flutter on my newly installed 8k
No problems keeping the house warm and efficiency is decent, way better than the 11kW it replaces.
Zoom in and the swings look quite large with almost 1kW of heat output swing
The flutters start as the setpoint and the flow temp converge. Move the setpoint further away using the LWT offset and the flutter goes awayā¦ until the two converge again
As its the flow temp, rather than the return that flutters, I also see the delta flutter
In the next screenshot I have lowered the LWT offset @1615 to -2 and the flutter goes away
I just wanted to chime in and add another data point here for reference, but Iām seeing the exact same thing. Iāve only had my install for 2 weeks, and this is mostly noticeable when external temps pass 10 degrees.
For reference Iāve got an 8KW Daikin from Octopus. Iām using a Shelly EM to monitor input, and ESPAltherma to monitor outputs, flow rates etc. Pure WC leaving water control, no matroska or modulation.
My deltaT is set to 10 degrees as Iāve found that to be the best for maintaining a steady flow rate. As you can see, the target, return and external temps are all pretty much flatlined for the period. The āfluttersā last for about 1 minute each. In the 1 hour period above, the peaks and troughs for flow temp vary between 32.3 and 31.7 degrees, heat output bounces between 1500kw and 2300kw, and electricity input bounces between 280kw and 460kw. During this whole period my flow rate is a fairly steady 6.9l/pm to 7.1 l/pm, and my delta T sits around 4.5 degrees.
COP for the duration is 5.3 so I donāt actually know if this is a problem or not. Based on what Iāve read elsewhere, the Daikin prioritises a steady return temp which is what I am seeing here, and given that the compressor isnāt fully stopping and starting, maybe this is by design? Iāll let more experienced people chime in with their thoughts, and Iām happy to answer any questions about my setup, but hopefully this will help.
