Ecosy+ Hampton Highline 5Kw defra by Stove world UK. AIR Controls 

Yes thats it as a rough guide. I never touched the screw and left it defra approved, i am not in a smoke free zone either. I believe if you adust the screw it can close off all the air , it should extinguish the fire and create smoke. Wood burning is almost a science, type of stove..direct air...length of flue for draw....type of hardwood...type of softwood....how well seasoned...the amount of wind outside the list goes on. Trial and error plays a part too but if the glass goes black something is not right.

@@MrLinzard thank you, my trial and error starts tonight, we are using short spells, as recommended initially to cure the new stove casing paint. But due to my ignorance, the glass had got a bit black. But I do have a good Stovax glass cleaner. THANKS

No fully out it burns hot and fast but as the air is at max it will push heat out the flue. Fully out is good to light or refuel. The hottest and most efficent is probably half way out, the flames dance, the heat is imtense and the logs last for longer. If the air is closed it will almost choke the fire out or if adjusted slightly it allows the stove to stay alight overnight. It also depends on the type of wood ie soft or hard and also how dry or seasoned it is. I hope this helps.

Thanks, got it working better and cleaner tonight. I don't need it on but a couple of hours at a time to cure the casing paint gently.