Anyone monitoring a new R32 Ecodan?

ajdunlop · 2024-12-10T09:27:30.685Z

The input power does drop a bit each time (in the bit below it is running at 1,179W but drops to around 700W before ramping back up again) but the output collapses to nearly nothing (over 4.5kW down to around 1kW below) .

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In cold weather I do sometimes get the DHW cycles where the input power drops back a bit but the output goes to near zero with input power continuing. These are much rarer when I put the hot water into normal rather than eco mode.

ajdunlop · 2024-12-10T09:29:35.206Z

It just seems very unstable. Why drop the input power back so quickly when I guess it could slowly back off and find a lower stable input power.

matt-drummer · 2024-12-10T09:30:01.378Z

Hi John

@johncantor

This looks very similar to our Daikin issue?

ajdunlop · 2024-12-10T09:31:44.829Z

matt-drummer:

This looks very similar to our Daikin issue?

Yea for sure it looks like digging into one might help with understanding the other.

ajdunlop · 2024-12-10T09:40:44.552Z

I had a very quick look through some other 8.5kW Ecodans and found a couple of examples where it is doing the same sort of thing bit not as dramatically as mine. Probably worth having a more extensive trawl through all the R32 Ecodans to see if there are other examples.

Emoncms - app view - from this system: HeatpumpMonitor.org

another
Emoncms - app view - from this system: HeatpumpMonitor.org

Timbones · 2024-12-16T14:01:20.680Z

2 posts were split to a new topic: Poor DHW COP on an 8.5kW EcoDan?

ajdunlop · 2024-12-20T08:23:01.957Z

I’ve had another complete failure to get up to temperature on a DHW run last night. It was a few degrees above freezing so cold but nothing excessive. Where the flow rate drops to zero the immersion was brought in.
https://emoncms.org/app/view?name=MyHeatpump&readkey=9b87718992b6ed5756d94d4288059a6f&mode=power&start=1734663190&end=1734674220&flow=1

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ajdunlop · 2024-12-20T08:24:18.869Z

Looks like it backs off to settle at a max flor temperature to give the tank time to get up to temperature but then output collapses. Compressor still consuming for a bit but no output.

ajdunlop · 2024-12-20T08:25:27.968Z

Same run but black line now showing tank temperature

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johncantor · 2024-12-20T09:33:45.920Z

Gosh, that is a dramatic ‘crash’. The Carnot COP before and after is quite normal, so surely the refrigerant quantity is not a problem. It sounds like an expansion valve too open, and surely due to a sensor giving incorrect values for this very brief time. Ecodan do tend to slow down as you say, for good reason, but it’s staring to slow at only 53c this seems surprisingly low. Maybe that slow-down is the start of it ‘crashing’… I dont know.
It would be good to get a temperure probe on the discharge and also on the evaporator about 10-20% along the coil. If the LEV closes consideranly, all evaporation occurs in in a small area, hence the temperature drops.
[ Ignore this last comment… an alternative possibility for drop of output would be a closed valve. However, this would cause a pressure fault, and power input would drop. We are not seeing pressure faults here. its not a closed-valve problem]

Ivailo_Stefanov · 2024-12-20T09:44:11.795Z

Maybe a little correction from me - I expect the EEV to be open more than needed…

johncantor · 2024-12-20T12:06:32.231Z

Ah, yes… sorry, too many things on my mind! well… The normal thing we are seeing here (we think) is reduction in heat output due to liquid going to the compressor, and some evaporation happening in the wrong place. However, another possible drop in output could be a closing of the valve. This was common once when mechanical valves fail closed. However, it would stop on the low pressure cutout. Ignore my thought of looking for low pressure, my mind was in the past!!

ajdunlop · 2024-12-20T13:32:57.265Z

johncantor:

Ecodan do tend to slow down as you say, for good reason, but it’s staring to slow at only 53c this seems surprisingly low.

My DHW is set to 48°C so I guess maybe it goes to 5°C higher than that.

ajdunlop · 2024-12-20T13:34:35.266Z

johncantor:

It would be good to get a temperure probe on the discharge and also on the evaporator about 10-20% along the coil.

I wonder what the best way of setting something like this up would be.
I guess I could maybe hook an ESPHome with a couple of temperature probes attached.

johncantor · 2024-12-20T14:16:45.907Z

You could maybe use an EmonTH with one or two ds18b20 probes on it??

F1p · 2024-12-20T16:47:12.872Z

To not get up to 48°C in 1hr 20min seems suspicious - like the 3 way valve is passing and some of the heat is being delivered into the heating

Or is it hitting the 90min limit in the controller?

johncantor · 2024-12-20T17:03:37.846Z

The Carnot COP for when its heating from 25-50c is about 43% . that is only a little bit low. (Mine is around 46%). Heat output 5.5-6kW.

Rachel · 2024-12-21T15:18:49.837Z

@ajdunlop I occasionally have the same problem as you, but not quite so dramatically. A week back I decided to move the temperature sensor to a different pocket on the tank; it didn’t make any difference, but then I realised that the installer had not pushed it all the way in originally and had then put a cable tie on which meant that I couldn’t push it all the way in either. I’ve now rectified that and I’ve added some heat sink compound to the sensor. The result has been dramatic in the change in reading and the speed with which the sensor now picks up the rise in tank temperature. I’ve done the same with my other tank sensors. You can see that I got an instant increase in measured temperature of nearly 10C and that the ‘mid T’ (which is actually located about 2/3 of the way up the coil) now sits with the top C. The ASHPTDHWTemp probe is in the same pocket as the top T sensor, but I only read that from the API every 15 mins.

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This image is from before I fixed the temperature sensors and you can see the CoP drops below 1 , 40 minutes in. Overall the temperature rise here is about 10C over an hour.

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This image is from the new sensor arrangement. It’s a slightly lower temperature rise of about 8C, but it does it in about 30mins. The CoP is much higher (slightly higher ambient) and there is no collapse below 1.

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Now I’m going to disappoint you by saying I have seen it do the weird stuff since, but only once so far and that was a 3C night run. You noted that it does it more in ECO mode, so if the problem is that the ASHP DHW sensor isn’t getting an accurate reading, that could be a problem (more in ECO than NORM) because it’s possible that the ASHP isn’t ramping the flow temperature fast enough - i.e. the tank temperature is getting to the point where it’s possible that the bottom part of the coil is putting heat into the tank and the the top part is taking it out again!

I don’t think it’s going to solve the problem completely, but just making sure those sensors are pushed fully into the pockets and ideally putting some heat sink compound on them might help (if you’ve not already done that).

ajdunlop · 2024-12-29T21:48:46.588Z

@Rachel after your post I put some paste on the lower sensor that is used by the Ecodan when heating up. However I have since had another bad DHW warm up.

I did also put paste on the flow and return sensors connected to the FTC. This looked like it does make a difference to how quickly these sensors change with changing temperature and much more closely match the in pocket sensors of my EmonHP. This has allowed me to remove the adjustments I had applied in the FTC settings.

I think this might help the performance generally but the dips are still happening when the outdoor temperature increases and the heat pump is trying to reduce down the flow temperature. It looks like the dips are more likely something to do with the control of the expansion valve or the refrigerant temperature sensors.

I really think installers should really always be installing the flow and return sensors in pockets or there could be all sorts of performance issues caused by saving a few minutes and pounds.

ajdunlop · 2025-01-03T17:03:57.438Z

I’ve been following this Dutch forum that discusses Ecodans:
Mitsubishi Electric Ecodan Lucht/Water Warmtepompen - Duurzame energie en installaties - GoT

Some interesting things when things aren’t lost in translation.