Since installation (by an official panasonic installer), the heatpump is unable to heat DHW above 50C (maybe 52C). The installer basically said that the heatpump will never be able to heat that high and I shouldn’t bother. The manual says otherwise and I have a feeling the guy doesn’t know much because when he was servicing the pump he was constantly on the phone asking how to check stuff from some other guy.
This is the behavior I have observed:
When setpoint is 45-50C - DHW will heat up to around 44C, then compressor starts turning off and on as it tries to hit the setpoint and it can be quite a few offs and ons before it does so (if it even reaches).
When setpoint is 40-45C - DHW will heat up in one go. Delta is set to 10C. I tried changing the Delta to be more or less, but that doesn’t help. It seems that as soon as the DHW temp reaches 44C - the heatpump is just unable to pump heat into the DHW tank.
I have Homeassistant attached to it via heishamon for monitoring and this is what it looks like https://i.ibb.co/qLxwftnX/image.png The top graph is the Compressor Start/Stop counter and it’s climbing like hell. Bottom is the temperature graph, mostly interested the green (Outlet), red (Inlet) and yellow (DHW) lines. At first it climbs and maintains the the temperatures until around 16:00, when the DHW hits around 44C and then it just stops, the compressor turns off, then after a minute turns back on, then off again and is now stuck in that cycle until DHW time ends or I switch it off.
Smart DHW - Standard/Variable - doesn’t matter which, same issue
Pump max duty - 0x99 - I lowered it in hope it might do something, but I can’t tell if it did anything at all. Raised it back to the default 0xFE and same behavior
DHW is set to max 30min, heating - 4h.
Another thing I’m currently trying is to set it to quiet mode 3 which is what I found on some forum that supposedly helps with such off/on behavior.
Does anyone have any idea what else to try/test? Cause this is driving me insane. I have solar panels, I would love to just pump heat in and leave it for the night and have hot water in the morning instead of needing to turn on the DHW early so it heats up. I can’t run disinfection mode either. Recently got a bathtub and I have to fill it halfway, wait 20min, the fill it fully otherwise it won’t be hot enough.
The coil area may be part of the issue. The link to the graph shows flow temp from the ASHP is only getting to 53ish degs and is then being told to stop heating. It should be going up to around 60, unless, something is triggering it stop heating. Is the trend you linked to, for a set point of 43/44 degs?
It is rare for an R32 to get DHW hotter than about 50 as your installer says, which is what you say you see. The flow temp from the ASHP may hit 60 but then you have distortion caused by the heating coil, so cylinder temperature will never get there. The smaller the coil area the larger the distortion. You have about 10 degs difference in flow temp and cylinder temp so getting to 50 is about your limit.
If you want it hotter than 50, use your immersion.
I would also reduce your heating window to stop any triggering of the heat pump once it’s done its thing. Plus I would operate a single target temp for the cylinder not multiple different setting.
The trend I linked to is from when the temp was set to 60C. It looks even weirder when it’s already at 44C when it switches to DHW mode: https://i.ibb.co/4nnz2Bkx/image.png It just oscillates around 42C, doesn’t even try to go for that 53ish C it did when the current temp was below 40.
According to the datasheet, the HeatPump should be able to heat DHW to 60C at -10C. But it can’t even reach 50C with +35C outside.
I don’t have an immersion heater and getting one just for this feel like being cheated.
It’s on a small window - 30min, I was just experimenting to see if it’ll ever even reach above 50C
The target temp I want is 50C, I have to keep it at 40C so it doesn’t kill the compressor.
I found with my previous heat pump (not Panasonic but same is likely to apply) if the dhw target is not met (i.e. flow temp hits 60 degs) the heat pump control drops the target by x degs (internally not your adjustable figure in the controller) and keeps doing this until it is happy. The only way to reset was to de-power the whole heat pump and then apply power again.
60 Deg DHW for an R32 heat pump is dream land, unless immersion is employed. I would set to 48, shorten reheat time window to 90 mins at a time. Cycle ashp power, see what it does and report back. Then understand max flow temperature from ASHP before doing anything different.
If I set to to 40C or 45C and to heat for 30min - it works fine, but I don’t want 40 or 45C, I want 50C or above for when I need it.
Power is cycled daily - off for the night. And we have power outages sometimes, so the heatpump has been off many times. It might be ‘stuck’ but power cycling, turning it off, setting lower temperature is not making it ‘unstuck’.
I suspect the 60degC that you reference includes the action of an immersion heater. Other brands (like my R32 Samsung) claim the same maximum number, but the small print reveals that - as @Johnmo suggests - the LWT will likely only get your tank to 50-55degC at which point the controller switches on the immersion to get to 60degC. I’m not familiar with Panasonics, but you may find that you actually have 2 or 3 separate setpoints available on your controller - the maximum LWT allowed, the maximum DHW tank temperature using just the heat pump, and the maximum including the immersion heater. If you do have them, is it possible that you are mixing the settings up (even though you don’t actually have an immersion heater)?
If you don’t have an immersion, how do you disinfect your DHW tank? (This would explain your “I can’t run disinfection mode either” comment above.)
Out of interest, I just took my Samsung to its DHW limit, to test @Johnmo’s assertion (“60 Deg DHW for an R32 heat pump is dream land”). I have physically isolated my immersion from the HP, and use it only manually, so we can discount this. My HP stopped heating soon after the LWT reached its setpoint of 70degC (though there was a 2-3degC subsequent overshoot - system thermal inertia, I guess). At that moment, the DHW tank base temperature was 51.5degC, compared with my target setpoint of 55degC. Thermal inertia over the next 5 minutes took it up to 52.8degC. The tank top temperature after that was about 59degC. So not exactly dream land - I almost got there just with an R32 HP (no immersion heater).
@Johnmo’s comment about tank heating coil size is well made, but for any given LWT even an undersized coil will get the tank to the lower of setpoint or LWT eventually. Something else seems to be happening in your case to stop the tank heating well below setpoint. Is there some controller hysteresis or timer setting that you have overlooked or set incorrectly? If not, have you always had this DHW temperature constraint?
(Re-reading this, I wonder: Have you set maximum allowed LWT too low, perhaps?)
Even if it needs immersion heater to go 60C, it doesn’t go 50C without really awful off/on. I don’t see any LWT or anything similar in the controller.
Panasonic has a disinfection mode where it’s supposed to hit 60-65C
If my DHW would reach above 50, even those 52C then that would already be good. The sensor is in the middle of DHW because the installer said it can’t be at the bottom when I first reported the issue (he’s the one that installed it at the bottom to begin with, so I’m not even gonna comment)
I cannot find anything related to this in the configuration or manuals. I have tried leaving it in DHW mode for 24hours and it just wobbles around that 44-48C. Yes, this has been from the beginning and it’s frustrating beyond point. I can live with 40C for daily use, but when I want to run a bathtub or want to save on power by using solar, it’s not possible.
There’s no LWT configuration that is available to me and if it’s available to the installer than he didn’t change anything when he came out to check on it.
Hmm I think this may be significant. In the output you included in your original post, something stopped the heat pump when LWT hit 53degC, and it may not have been your DHW tank temperature. I couldn’t readily find an Aquareus operating manual on the Interweb, but are you sure there isn’t a factory setting in your controller that is somehow limiting LWT?
It wouldn’t surprise me if your installer kept you in the dark deliberately - my installer told me not to touch the factory settings - he’d do everything for me (at a cost, of course…)
I couldn’t find anything in the factory setting or even the debug settings.
I don’t care if the installer will do it for me, I just want it done. The issue is that my installer is claiming a no-go. I guess I can just report him to panasonic and see if that’ll start a light under his ass
My sympathies. Samsung have a pretty good web helpdesk for owners; I wonder if Panasonic have? Or maybe there’s a self-help discussion group devoted to Panasonics?
Finally, maybe “LWT” may not be the term Panasonic use in their manuals. Assuming you have weather compensation available for space heating, what do they call the water temperatures associated with setting that up?
There’s cooling/heating compensation curve, but it’s completely unrelated to DHW. The curve is set to heat to 50C at -20C outside. I can bump it to 60C and see if that’s related.
…that won’t make any difference to DHW. It was the terminology I was referring to - some phrase other than “LWT” that you could search for in your factory settings.
That manual is also for an R32 HP, and the page I’ve referred to has configuration instructions and a graph for a booster heater usage. That suggests 53C from the HP, with the booster taking it to 60C.
The KIT-WC09K3E5 is indeed a split, the spec sheet is available here.
There’s also this monobloc installation manual here, which again talks about configuration of booster heater for DHW disinfection, which for sure gets you to 60C. It’s somewhat easier to read than the other one. There doesn’t appear to be any means of setting the DHW “circulation water temperature” - I assume the HP does what it has to do i.e. max it!
I note that the Panasonic installation instructions prefer use of a buffer tank or LLH. Obviously that doesn’t affect the DHW production, but as people on OEM point out, it can be a source of inefficiency on the heating side.
I have a Daikin R32 Altherma, and it would really struggle to get to 60C - the disinfection cycle uses the booster (immersion) which is controlled by the HP.
The fact that flow temp just caps out at 53°C is the real puzzle here. You’ve already ruled out Delta T and the DHW mode settings, which tells me it’s probably not a simple control tweak. That hard ceiling suggests either something is physically limiting it (blockage, sensor reading wrong) or there’s a config parameter you haven’t found yet that’s telling the pump to stop. Since the installer was clearly clueless, I’d wonder if he set something during commissioning that’s now locked in. Might be worth checking if there’s a flow temp maximum or DHW coil protection limit buried in the menus.
Good detective work, @John! @Kazunekit p28 of the manual John links to makes it clear that 53degC is the maximum LWT temperature that you can get using the heat pump alone, and that you must have an immersion heater to go any higher. This appears to be a hard constraint for this particular model of heat pump. So your options are to fit an immersion heater, or to replace the heat pump with one that can produce a hotter LWT. (If you can only get your LWT to 53degC, needless to say your DHW will be even lower, because the heat pump switches off as soon as LWT = 53. It doesn’t sit there maintaining 53 - if it did your tank would eventually heat up to that temperature.)
