@editor thanks very much for checking in!

The system seems to be working well at the moment, I don’t have any fact and figures (as I’m not sure how to work it all out!!) but our bills are much more reasonable than last winter and the house is a more constant temperature! I am now the heat pump expert on our little road 🙈🤣🤣🤣
I’m extremely grateful to those who helped me last year ☺️

@curlykatie really pleased to hear that, and equally so that you are sharing the knowledge with the rest of the street. 👍

As a lucky German guy who was able to find some tips in this forum, I'm getting desperate to set the right parameters.

I opted for the Midea heat pump (Mod. MHC-V12W-D2RN8-BER90) out of a time crunch, but it doesn't do what it's supposed to and the technician either has no idea or doesn't want to help me. This has been going on for 6 months now, but I can't get any answers to simple questions. My simple question to the service guy is; Which 'Profiles' do I have to chose for Low and High Temps? (see attached picture). (Nied-Temp=Low, HO-Temp=High) 

 
During this thread I learned to adjust, but I'm still missing the entry point...I think, based on my region I have to select '9' but without knowing High or Low and why. 

During the installation he showed a clear table/diagram but it's not the same like in the manual. 

Anyone have an idea?

@iwolf - I have a very similar if not the same heat pump. Yours has a suffix, perhaps that means it is the German model. I don't speak German I'm afraid so some things may get lost in translation but if the high/low you refer to are the high/low points on the weather compensation curve, then you get to them through (in English) the 'For Serviceman' menu, Menu 3 'Heat Mode Setting' items 3.8, 3.9, 3.10, 3.11, The first two are the Leaving Water Temps (LWT) for the left and right hand ends of the curve, the second two are the left and right hand outdoor air temps. To set a curve (yours may be more extreme!) of 55 degrees LWT @ - 4 outside for the left hand end, and 35 degrees LWT @ 15 outside for the right hand end, settings 3.8 to 3.11 would be, in this order, 55, 35, -4, 15. 

The photo you have attached to your post shows I think the menu where you turn weather compensation on, as opposed to fixed LWT. You want the middle one selected, as you have, and then your main (and I presume only) zone 1 only set to heating on, the second entry in the list. I think it may ask what curve you want, if it does, it is probably curve 9, Midea's standard weather compensation curve.

The full Midea service manual (in English) has been posted online both here in the forum and elsewhere. It shows all the settings, including the 'For Serviceman' settings, which may be what your installer showed you. I'm sure google will find you a copy, maybe even in German.   

Many thanks for sharing your thoughts. Really helpful. I forgot to say, that I have radiators installed (so I need a higher flow temperature)
I now also understand the parameters 3.8-3.11. (sometimes I feel I already know way more than the service guy)

But how do these parameters fit with the compensation model from my attached screenshot? By that I mean; which parameters are used? 3.8-3.11 or if I select the weather compensation curve from the screenshot profile 9?

My problem is, that I want (or better, I think I want 😉) to let the weather decide which flow temperature to set. 

Hmmm...looks like I found the answer. When I select 9 as the profile (my picture, second line, Zone 1 H-Mod High Tem) it uses 3.8-3.11 parameter temperatures. 
When I select profile 3 is uses two different temperatures, but I don't know if then 3.8 and 3.9 temperatures are being 'overwritten' 

Posted by: @iwolf

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My problem is, that I want (or better, I think I want ) to let the weather decide which flow temperature to set. 

That is exactly what weather compensation is, and it is what you want. One zone, no TRVs (with very rare exceptions) and weather compensation. Strictly speaking it is setting the LWT (flow temp) by outside air temp alone, rather than weather, and so does not for example take into account other weather effects like solar gain, but hey, weather compensation sounds good for marketing!

A short while ago I posted a sample weather curve:

What settings 3.8 to 3.11 do is set the coordinates for the two blue dots. In simple terms, your wired controller then reads the outside air temp (only it does it in the heat pump, and so is often subject to recirculating cooling exhaust air) and then sets the LWT by reading off the corresponding LWT value from the curve (only the actual LWT almost always cycles, infrequently so that's OK, and the average LWT is sort of about your set LWT).

I can't remember why, I think it is somewhere in one of the manuals where they illustrate the curves, but 'curve 9' is the one you want.   

Hi @iwolf  I wrote something about this on a German forum that also covers this ASHP and the many clones. Maybe it is of help. I do note that I have not yet ventured in different weather curves for different zones (as your display shows) and I am pretty certain that is just impossible. One curve for all. You can write me on the German forum if you like. Tschüss!

https://www.photovoltaikforum.com/thread/232887-suche-nach-passender-wp/?postID=3951798#post3951798

@mphb - thanks, a useful link. Using google translate, I found the post contains this:

"There are 8 heating curves pre-programmed, with "1" being the curve with the highest temperatures and "8" being the curve with the lowest.

You can determine heating curve "9" yourself, in the "For technicians" menu and then submenus 3.8 to 3.11 as follows.

T1SetH1 (3.8) is the temperature of the heat pump water at outside temperature T4H1 (3.10) on the "cold" side of the curve.

T1SetH2 (3.9) is the temperature of the heat pump water at outside temperature T4H2 (3.11) on the "warm" side of the curve."

This jogged my memory - curve 9 is the custom curve, the one where you get to set the end point coordinates for the curve. The other curves, 1-8, are presets. You want to use curve 9 because it allows you to set a weather compensation curve that works for your building. 

Many thanks @mphb and @cathoderay. Didn't expect so quick help on my sad journey into which you have brought much light and warmth. Thank you very much

…but the journey continues…Energy consultant came by and made the calculated setting on the radiators through the valve. As a result (pure assumption on my part that this is the starting point of the problem), the heating no longer works and runs to error message E0/E8 and no longer works at all. Water flow fault.

Service guy still has no idea and it trying to fix it via venting (if this word works) 

Posted by: @iwolf

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Water flow fault.

Not sure, but I think that may be the inline filter by the heat pump is blocked. Mine has a quarter turn valve to close of the pipework, and then you unscrew the base to get at the filter cage/basket. I've never had the error, only opened the filter to check/clean it, but I seem to recall this is a known Midea problem. 

Goes without saying I hope, turn off the heat pump before closing the valve!

I suppose another possibility is the 'energy consultant' dialed down the lockshield valves so much that that the heat pump considers the flow to be obstructed?