My Melcloud shows "Zone 2 is not operational on this system."

Expression.Error: There weren't enough elements in the enumeration to complete the operation. Details:  

It won't work for me.  I have one zone and as per your quoted requirement, I need two.

OK. I have only one zone as well, but that just means Melcloud shows the second zone as at a constant -39. As a result, I assumed (not being able to test otherwise) that the spreadsheet would only work with up to two zones, not precisely two. If it's not working for you then it shouldn't be too difficult to amend the calls accordingly.

It won't work for me.  I have one zone and as per your quoted requirement, I need two.

The data source you are using behind this all assumes that you only have one location (i.e. house), that you only have one heat pump at that location and that you have two zones to be heated.

I have only one zone 😌 

However, your work is appreciated.  Thank you for sharing.

My pleasure. Do let me know if it works for you, though; I was only able to test with my account so confirmation is always good.

The data source you are using behind this all assumes that you only have one location (i.e. house), that you only have one heat pump at that location and that you have two zones to be heated.

I have only one zone 😌 

However, your work is appreciated.  Thank you for sharing.

It should do roughly what you wanted. Some bits to bear in mind, though....

• The first tab is for your settings. Here is where you'll put your start and end dates along with your Melcloud username (i.e. email address) and your associated password.
• Once you've put those four details in, all you need to do to run it all is to go to Data on the menu bar and then click on the button "Refresh All". This assumes, of course, that you trust my coding, so feel free to be as suspicious and wary as you would like; that's exactly what I would do.
• The data source you are using behind this all assumes that you only have one location (i.e. house), that you only have one heat pump at that location and that you have two zones to be heated.
• Melcloud's API has a few quirks in the way it works. For instance, it will only give hourly data for the current day and even then it's only for the internal temperatures, so I have left that out. Similarly, if you want to look at the past month or less it will give you daily data but if you put in dates more than one month apart then it will provide monthly data points instead. Nowt I can do about that, I'm afraid. There's nothing to stop you, however, from putting in a start and end date in, for instance January 2022 and getting daily figures from that far back - it's not a problem of lack of data on Mitsi's part.
• Since the data points mean different things based on the distance between start and end dates, I haven't even attempted to add any dates next to the data. Suffice to say whatever comes out is in chronological order from oldest at the top to newest at the bottom.

If you want to see the guts of the spreadsheet you can go to Data on the menu, then click on Queries & Connections to bring up a panel on the right hand side. In there you will see a query called (imaginatively enough) Query1. If you click on it and select Edit then you'll get into the Power Query Editor. Clicking on the Advanced Editor will then show you the entirety of the code I put together.

I hasten to add that if you aren't interested in the code, there's absolutely no need to take a look. However, if anyone is actually interested in how it's working then I can post more of an explanation later.

Overall, the spreadsheet is just a proof of concept that is intended as a working starting point for people to extend if they really want to. Using Excel to get API data is not entirely novice stuff but nor is it the domain of a gifted few. There are some underlying concepts to get to grips with if you want to do it yourself, but if it raises enough interest it's something that could theoretically become the basis of an RHH article.

There is, but you’ll have to give me a wee bit of time to sort out the easiest way to show you. Leave it with me.