Hi Steve,

Came across the post as I have the same issue. Have you found a solution to this?

My wall terminal loses connection every 20-30 days. When this happens I still see the wall terminal as a client on my wifi. But can't access the ASHP anylonger via the app. I now have WiFi set up to be on 2.4 GHz only, changed position of nearest access point, and tried various other WiFi tweaks. No improvements. Only solution is to power cycle.

Any hints or tips are much appreciated.

@stevet — sorry I missed your post first time round, @schnetf's post brought both posts to my attention.

I also have a Midea heat pump as do others on the forum and I think it is fair to say the general consensus is that the Midea app is a load of see-are-ay-pee. Setup is quirky, the app tells you very little, and lost connections are common. Depending on your inclinations, you can either make do with the limited data the app will give you, and accept you will have to reconnect from time to time, or, at the other end of the scale, set up a wired connection to the wired controller and monitor your heat pump some other way. This is what I do, and there is more than one way of doing this. More details available if you want them.

Posted by: @stevet

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Currently we have an extremely basic set-up using wall thermostat and a schedule that makes some use of our overnight 7p EV rate for water and to get slightly warmer before 05:30am . We have water set to 49C at night and 45C during the day.  We mainly have 19C for the day, with a 18C between 6am and 2pm, then back to 19C.  Puraflow did not give us any information of using the weather compensation.

So called set-forwards that bank some heat during time of use tariff cheap rates are another subject, but the thing I have spotted here is that you are not using weather compensation, and rely instead on timers and thermostats. The general advice with heat pumps is don't do it! The whole idea is you run low and slow all the time, with the weather compensation adjusting the flow temp (temperature of the water leaving the heat pump, often called the leaving water temperature, LWT) according to the outside air temp (OAT). Basically, as the OAT goes down, the LWT goes up. When correctly set up, it works extremely well.

Are you comfortable using the wired controller? If the answer is yes, I can run through how to set up weather compensation. 

@cathoderay   -Hi, since this early post I have now read 100's posts and become a convert to a WC curve, ditched the thermostat settings and use the power of the curve! After much slight adjusting now have the following settings that keep out house to a comfortable (to us) 19.5C or thereabouts 27 at 14c and 40 at -4, worked perfectly over the -7C cold snap.  Our daily usage varies between about 14KW and 41kw with a average COP through this period of 3.4 for January which I think is pretty good, lowest was 2.8 and highest was 4.12.  I survive with the useless APP, though it has not disconnected so far this month which is a small win. I have lost instant updates and can only get daily stats.  For those with solar it has been pretty good, so far daily average generation is about 10KW.

@stevet — thanks very much for the feedback, an excellent outcome by all accounts! The wide variation in daily use depending on the outside air temperature (OAT) is normal, because the heat pump takes a double hit in cold weather, it needs more energy anyway, and on top of that, its efficiency (COP) also drops, while in warmer weather it gets a double benefit, it needs less energy and it runs more efficiently. During the recent cold spell, I had COPs just below two, but this morning, with an OAT of 10 falling to 7°C overnight, my 24 hour COP is 4.2. In milder weather it is often around 5. It all averages out OK in the end.

The other thing to note with Midea heat pumps is that they use cycling to modulate (control) output throughout most of the OAT range, apart from the 'sweet spot' which happens when the OAT is around 7-8°C, when the unit runs in steady state. You will come across people saying cycling is bad, and it is if it high frequency cycling ie several times an hour, then it is bad, but Midea units use low frequency cycling, maybe once an hour, and that seems to be OK.

That APP is indeed not much COP, so to speak, but that I find is not uncommon with apps. I suspect it is because there is a belief that everything must have an app these days, even when they add very little, and all too often the app becomes a token app, as it does with the Midea app. They also raise questions about privacy, because often they send data home, and only then ever so generously allow you to see a subset of what is after all your data. The answer for those who want to do it is to use local data collection, but that does require a bit of setting up.     

@cathoderay Hi , I have spotted the cycling of the Midea and with some research worked out it is OK, not too frequent.  This forum took away my concerns with the increased use, though it is not rocket science that all ASHP's will use more energy to extract heat as the temperature drops. Overall I am pretty happy with our unit, no so the support, it has been this forum that has provided the help and assistance I needed to get the unit working as it should.  I have to admit any ASHP comes into it's own when combined with Solar, batteries and low overnight energy tariff.

@stevet — the lack of after sales customer service is a big problem in the heat pump industry, as you will have seen while reading up on things. Many installers want to do a hit and run installation, and to achieve that they wilfully set the heat pump in such a way that it will sort of work, but at great cost to efficiency, eg high fixed flow temperatures. The customer either has to put up with that (and become another heat pump detractor because of huge bills) because through no fault of their own — you should not have to go to heat pumps boot camp before having a heat pump installed, the installer should tell you what you need to know — they don't know how things should be set up, or do a lot of DIY research, as you have done. If @transparent reads this, he may well add that not providing adequate instruction on use falls foul of the Building Regs, but most customers won't know that, and installers are hardly likely to point out they are not doing what they should be doing. It is unsatisfactory to say the least, but it is also very difficult to do anything about it, unless and until the industry gets its act together, and with that we enter the land where pigs might fly. A slower but perhaps more achievable resolution is to hope that as heat pumps become more common, it becomes common knowledge that they should not be run like fossil fuel boilers, but rather low and slow, under weather compensation.

@stevet I don't know who started the 'cycling' issue but its often not as people think. The off time is the important part, ramping up and down is normal as can be defrosts twice an hour.

Posted by: @dgclimatecontrol

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I don't know who started the 'cycling' issue but its often not as people think.

I think it is one of those urban myths, 'cycling = bad', and as you say it is often not as people think, some heat pumps including Midea units use slow cycling as part of their normal output control mechanism, while a defrost is inherently a cycle. The reason I brought it up here pre-emptively is because some Midea owners discover their heat pump is cycling, and think oh dear that can't be good, when in fact it is normal and OK as long as it is slow cycling, around once an hour or thereabouts, which it almost always is. My heat pump has been cycling for the last 24 hours, mostly at around the once an hour rate (the big spike is DHW heating):

@cathoderay   - slightly off topic. Driving home from the gym this afternoon  - Radio 2 had a phone in on Solar Panel, Batteries and ASHP's  - primary focused on Solar panels. Not sure how they selected the callers, but 9-10 did not recommend their Solars. One said he paid tax on revenue, other said amount generated was negligible, property lost value, could charge his EV properly. Their was an ASHP customer who's supplier went into administration and was left with a partially installed system - from what I gleamed she just needed a WC curve.  

Personally I would say the Solar and Battery and ASHP was the best decision I have made, used properly, exporting as much as possible in the summer and combining with low tariff and battery we both power our house and run our EV for pretty much £0, what we generate in the summer has paid for the winter. Part of the problem is developers stick on 2-4 panels and a 4kw battery and says that's it. We have 20 panels and would have installed more if I could.  As for the tax response, I just export and let the credit build on my account to be used as offset during winter. Going back to what you said there needs to be much more education and there is an onus on suppliers to up their game. 

Interesting to hear the experience from both of you. I also have PV, batteries, and cheap night tariff (which I use to charge the battery and instead try to export as much as possible during the day).

Coming back to Midea.

@cathoderay I am interested in learning more about connection to the wall terminal. Depending on the complexity, I am willing to give this a shot. The need for hard reset is annoying.

@stevet how did you set up the WC on the wall terminal and Smartphone app used by Midea? I know how to program the wall unit but it seems when I activate the curve via the app the wall unit settings are being ignored. Simple example, I set the flow temp to 48C at -4C. Yet when I activate the curve the unit changes to a flow temp of 52C although the outdoor temp is several degrees above the lowest point.

Currently, I do the WC manually. Meaning I set the lowest flow temp that keeps the house warm and at the same time the outdoor unit running at a low power demand for most of the time.

Posted by: @schnetf

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I am interested in learning more about connection to the wall terminal. Depending on the complexity, I am willing to give this a shot. The need for hard reset is annoying.

I wrote an almost complete guide on how to do this here. The only thing missing is the final instalment with the python scripts, which is now part written (and has been that way for a while...).

Posted by: @schnetf

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I know how to program the wall unit but it seems when I activate the curve via the app the wall unit settings are being ignored. Simple example, I set the flow temp to 48C at -4C. Yet when I activate the curve the unit changes to a flow temp of 52C although the outdoor temp is several degrees above the lowest point.

I think you may not be turning on weather compensation. It is possible to set the curve end points (in the 234 FOR SERVICEMAN menu eg your 48 @ -4 setting for the low outside air temp end of the curve) and yet still be running without weather compensation. Main Menu > Preset Temp > Weather Temp. Set tab then Select Curve 9 which is the custom curve, ie the one we set.

Edit: oops, forgot to add the link, now added above