Like you, I wanted to stop mine doing a quick burst to lift the last few degrees.
In fact I had so many things I ended up with target_water_temperature.py.
That online copy is about half the logic that I have running locally.
You’re in a difficult place trying to get this working smoothly when you only have a few levers you can use.
Hi there. I dont have an Ecodan but have Fujitsu Atlantic with the same issues…
m planning to install 4 DS18 temeprature sensors - descharge temp, suction gas temp, evaporation temp and subcooled refrigerant temp - and separatelly monitor the discharge pressure sensor of HP to make full analysis of Carnot cycle...I suspect also the EEV to be the reason for this anomaly and after that Im planning to monitor the signal from control board to EEV.
is the output reduced because the fins are icing up?
Its always with checking for ice at very bottom because if a system doesnt clear totally after a defrost, it can affect the refrigerant control indirectly.
There was no ice. It was cold and dry and no ice forming…This process is repeating in different outdoor temperatures.
It would only have been this morning that the immersion would have failed to run as I had turned off the Eddi when I was discharging my battery to the grid yesterday afternoon for the Saver Session. Actually quite impressed I remembered that the Eddi might think that was excess solar generation.
My hot water is set to be run on schedule during the Cosy off peak most of the time.
I don’t mind if the immersion is needed to get the last few degrees in this weather but it appears to get into this strange state where it’s using power but not producing heat and stays in that for a while before resorting to the immersion.
Not sure if it is relevant but I have quiet mode enabled on the middle setting. I should probably try turning that off or increasing it. I reduced it to stop AA being to aggressive.
I don’t think so as it appears to interrupt hot water cycles to defrost and dining the earlier stages of that one.
This definately odd. the variation in both power input and heat output should follow a fairly steady change… not ‘fall off a cliff’ as seen. However, if liquid refrigerant enters the compressor, it can reduce the heat outout dramatically. Is this a EEV, or EEV control issue? maybe you could watch the refrigerant discharge temperature. If this sensor is iffy, it could cause something odd like this, but its a bit of a long-shot. Running Information gives you these values, but its a matter of catching it happening… not easy. Can you get a sensor on the compressor discharge pipe?
I’ll keep an eye on running info 22 and 23 if I see it doing it.
I don’t have any way really of rigging up a temperature probe at the unit.
I though turning off Quiet Mode had stopped it happening this morning
But then this afternoon I get this (the last part it switched to immersion):
The water temp
Unfortunately I wasn’t around to check running info
I like using Trystan’s Carnot COP simulator. It shows what you should expect (calculated) compared to what you actually get . Here it shows your worst bits… Still pondering what it could be, and how you go about getting to the bottom of it. Actually my old R410a Ecodan is doing it a bit
This from the Ackworth Ecodan 8.5kWh looks to have a terrible time after the defrost in a hot water cycle, although not quite as bad as mine
Also a number of systems look to be down on the carnot valve for the first part when they are getting going after a defrost.
I managed to spot this run and took the following running information readings. Don’t know it they reveal anything?
13:41
012 - 0
022 - 60
023 - 260
13:42
012 - 0
022 - 60
023 - 260
016 - 40
13:43
012 - 0
022 - 60
023 - 260
016 - 40
13:45
007 - 0
13:46
012 - 0
022 - 480
023 - 480
016 - 0
007 - 9
The last readings where after the HP had given up and resorted to immersion again. At this point it has switched the 3 port back to heating but just running the circulation pump.
Mm, same thing has just happened from 13:00. I had switched to normal mode from Eco for hot water but doesn’t appear to have made a difference.
At the end of this one I had gone down to the cellar where our hot water cylinder is and could hear and feel the pipework reverberating slightly. I caught this happening just before the 3 port valve changed and the immersion was switched on.
Something is definitely not right.
Its odd.
Do the ‘ripples’ as the DHW valve changes at 13:02 make sense? looks like 1minute delay. Is pipe run long-ish? its this 1 min for the cold ‘slug’ to get from 1 sensor to the other? Anyhow, this is nota problem. What happens after the defrost at 13:35?? The return (green) rises to 42, and similar 1-1.5min ‘ripples’. Given the low input power, could this be either a slow compressor, or a closed EEV and very low evaporation pressure.
Mmm… so, looking at your 012 (discharge superheat)… its showing zero, and 022 (expansion valve position 60) is 480, is closed I think, and normal running on mine seems to be vagually in the range 80 to 150. I only have one entry of 60 in some of my notes, and this coincides with a ‘bad cop’ event. I would expect a low discharge superheat to close the valve (increase number?), so why is your valve open at 60… and why did mine do it? I dont know. What is code 023? its not on my spreadsheet
Zooming in on the flow and return data it looks like 30-40 seconds between ripples on the flow then showing up in the return after switching from Heating circuit to DHW circuit. On hot water the flow rate is around 19.7 l/m which I think to a 28mm pipe is around 0.5 m/s so would equate to around 7 meters each way. That sounds like it would be about right although there’s a good chance I’ve gone wrong somewhere there.
For the defrost during the hot water cycle the 3 port valve switches to the heating circuit. When it switches back I assume the 42 degrees is the slug of water sitting in the coil from before the defrost getting circulated around before the compressor kicks in and starts raising the temperature of the flow?
I was going off this (that I think you posted earlier) for the running info codes
That’s where I got the 022 and 023
Looks like my issues with hot water have gone away for a bit as warmer weather means it is less likely the hot water cycle will be interrupted by a defrost.
However I think this run from yesterday morning is interesting (Emoncms - app view) as it did eventually manage to recover enough to just about complete getting the cylinder to temperature rather than having to resort to the immersion.
curious indeed. It looks like when the flow temperure reaches 52-ish, it slows down to minimum. There are dip switches. is yours at 60C? It feels like if you avoid minimum power, it might not ‘crash’
If the MelCloud values for the DIP switches can be relied on then it looks like it is set to 60°C
