I’ve been trying something similar for a different reason - trying to find ways of slowing the DHW heating down with the aim of avoiding “air in the system” errors which I’m finding really difficult to resolve. I’ve set up a 1st pass using Eco mode with a lower set-point (40C) followed by a Comfort mode with finished set point of 48C.
I’m also trying setting to “Quiet mode” which again is a way of de-rating the heat pump as mentioned earlier in this thread.
Something else to try with the EDLA is power limitation (accessible from the Installer menu). I use this in continuous mode with a 1kW or 1.5kW limit for space heating, in order to stop the EDLA overshooting its target LWT and so to coerce it into stable operation in mild weather (i.e. force it to run at a lowish compressor speed at the start of a cycle). NB 1.5 kW limit for DHW is too limiting. Power limitation can also be achieved at 4 levels under control of something like what is described here: X85A smart grid / 4 level power limitation · raomin/ESPAltherma · Discussion #170 · GitHub. That should allow for differential limits for DHW and space heating under a range of operation requirements.
I’ll be going that way with a custom ESPAltherma board/software, as manual experiments are quite convincing at suppressing short cycling.
I’d be interested in seeing the difference in total input kWh for the 2-stage DHW cycles vs a single cycle under similar start/finish/external temperatures. My hunch is that although your COP figures look better, you’re using more electricity for a 2-stage cycle. But hopefully I’m wrong…
Is it possible in the MMI settings to have the power limit only apply to space heating?
You can dynamically set/trigger power limitation, but can’t remember if it’s built in or requires an expansion board, but there’s no setting to differentiate DHW/climate.
Yes, the selection of which level of limitation (or none) is selectable from a connector within the outside unit (see X85A smart grid / 4 level power limitation · raomin/ESPAltherma · Discussion #170 · GitHub).
The Daikin “demand pcb” is a complete rip off for what you get; it appears to be little more than 4 opto-isolators. You could use 4 relays instead and write/find some software to change the limitation level according to whatever rules you fancy. Using ESPAltherma is an obvious choice as the base for such work and you could simply change the power limitation level by watching for the 3 way valve position within the ESP device.
Lamentably, this has not been designed for ordinary users to take control!
At some point, I will be publishing the PCB design and “forked” ESPAltherma which I am working on now-ish but potential adopters will need skills with ESP8266/32, MQTT, and electronics assembly.
Nice, I remember thinking it just looked like relays.
Unfortunately mine (hydrosplit rather than monoblocks) doesn’t seem to follow any power limitation settings, even had back and forth about the solar matching smart grid controls which gets ignored.
Read somewhere it might work with current rather than power limitation but tbh I would only bother to set it over summer.
I have turned on quiet mode this afternoon.
I had used it before on my 9kW Daikin but had forgotten about it, so thanks everybody for reminding me of its existence.
Too late for DHW today but we’ll see how it goes tomorrow.
Too early to say for space heating but it seems much more stable.
My heat pump is often awful after doing DHW and returning to space heating taking hours to settle down, it rarely runs how it was before DHW even though everything is pretty much the same.
I have gone for quietest, no half measures here, just want to see the full impact.
I’m not worried about heat output as I never use more than 50% anyway.
The start of the space heating cycle seemed much gentler, not so aggressive and electricity consumption is down, but it is a bit warmer today.
The next few days will be a test, we’ll see.
I tried the ‘quiet mode’ settings for DHW before and it made the efficency worse.
Stepping up the power with the smart grid thing during the DHW using relays did work but not enough for me to warrent properly setting up multiple relays, adding code for ESPAltherma, and scripting something up for it to be automated.