I think I have improved my stove

Nobody can argue with your results. On my own stove there is a rear entry vent point that needs to be closed if I use an outside air kit. Maybe what you found is something like that.

No stove should run at 100% primary air, except to get a fire started. Even 40% seems high.

I would contact the manufacturer and see what the reason is for the new opening. Oldman may be correct that it's for an outside air kit, but still, something seems very wrong. Nothing showing in your manual?

All designs are a compromise of performance goals and installation flexibility, so what you did is likely just shift the compromise in your favor, for your set of circumstances. The guys in white coats (actually, we usually wear plaid and khakis) may have eliminated that part of the design for reasons that don't favor your particular installation.

From your description it looks like you have defeated an air emission modification. The most emissions on the stove are when someone fills it up full and then shuts off the air to try to stretch the burn time. By adding a set of tertiary ports (frequently hidden) that don't have air controls on them, the owner cannot turn the air off. It makes a big difference on emissions but does impact the flexibility of the stove.

I feel fairly confident when I say that most stove designers don't know what they are doing. It is not hard to design a good, efficient stove with easy to use controls.
It is hard to sell a simple stove to people looking for the newest and most modern model with "technology" in it. People are too eager to fall for a fancy sales pitch in search for something "cool" or "new" or "better".

A friend of mine bought a very shiny and expensive dodge truck a few years ago. It was a lemon and had engine, transmission, and many other problems. He insisted that it was a very good truck and paid many times to have it "repaired" only to find out it was not fixed or the part was replaced with the same thing it had in the first place. It cost him more than it was worth and he was finally forced to get rid of it.

A number of years ago we were looking at building a log cabin up north and wanted to be off grid. We were looking at popular vendors of cook stoves and we were shocked at the prices, which could easily exceed $10,000 for something that was an exact replica of a small antique stove with the same problems as the old ones, and with a lot of chrome added to make it look expensive. The stove we bought cost a third of that and exceeds claims by a fair margin. It does not look fancy or expensive, just great. Coaly has the same stove.

The hotter your secondary air, the better. 800 degrees is good and anything above that is even better.

SawdustSA said:

That reminds me, I need to remove the plastic off the user manual!

Click to expand...

Believe it or not, I just looked at the manual, and I couldn't find any reference to that hole. I guess you should contact the mfr. to find out anything. Or, just keep it the way you have it now!
http://www.yeomanstoves.co.uk/downl...epoint Installation and User Instructions.pdf

Excellent. I kind of forgot it was a new stove in a new house.