Yamaha-binding: How to set refreshinterval in Openhab 2.4

Is there any way to adjust the refreshinterval in openhab 2.4?
(As I understand (I might be completely wrong) manual thing definition is not possible?)

I appreciate any guidance.

Yes, there is a way. It’s well documented on the Yamaha bindings page:

I’m a little confused at the second part of your question, what do you mean by

manual thing definition

If you have set up your things in the UI (such as PaperUI), then you need to create a folder called things in /etc/openhab2/ (if you don’t already have one), and then a file in that folder called yoursitemapname.things

Obviously you need to replace ‘yoursitemapname’ with the name you need, but once you ahve done this you will be able to add code to define things rather than just use the UI (Don’t worry - you can combine both and don’t lose any of your existing things, just remember you can’t edit code defined things in the UI)

Many thanks.
To be honest, I was not aware that it was possible to make a things definition in a file
I thought that was an Openhab1 feature (that I’ve not been using), and that I had to rely on it being automatically defined through PaperUI

As I said, you can define things in both the UI and yoursitemap.things file. This is helpful as it means you can mix and match, essentially using the file and code to do the more complicated things that you are needing but also the UI to quickly and easily add in simple things.
The link to the full guide on the things file is here:

Hope you can do what you’re after. In case you didn’t know as well, the file and code method can be used for the items, sitemaps and rules (just search OpenHAB rules/items/sitemaps to find out how)
You should create them in the format -
< etc/openhab2/rules (yoursitemapname.rules)
< etc/openhab2/items (yoursitemapname.items)
< etc/openhab2/sitemaps (yoursitemapname.sitemap)

My main issue with the Yamaha binding is that the volume slider in openhab does not get updated when I change the volume using the IR-remote. I thought, maybe if I manually set the “refreshinterval”, this would get sorted.
However, it did not. ;-(

I don’t use Yamaha so i’m probably not the best person to ask about this, however it is clear that when the Yamaha detects an IR signal it is not sending the updated volume value to OpenHAB / OpenHAB is not configured to receive the value.

I suggest it’s probably Option 2. This is out of my depth but you need to find some way to tell OpenHAB where to received the updated volume level from, and how to interpret it. For example, with an MQTT server, the outgoing commands (publish) and incoming commands (subscribe) are defined separately.

I will study the Yamaha documentation and see if I can find how to do this, but in the meantime have a browse on Google.

Found it in the Yamaha Binding page:

Yamaha models return different input values on status update than required in the change input commands

One of the status updates received should be the volume, look at the Input Values subheading of the page and read that to get some example configurations.