[mheat]

Hi Dohan:

I'm not quite clear from your photos what the gas path in your oven is. It looks like there is a bottom firebox, with a throat at the back that runs past two hearth slabs, and then out through a stovepipe at the top of the upper chamber.

Here is a drawing of a traditional commercial Finnish bake oven, which has two chambers, with the fire in the lower chamber. It is a black oven, ie., you bake after the fire is out, and the flames go right through the chambers:

heatkit.com/graphics/pbakeo1.gif

Here is another oven with the firebox below the baking chamber, also with the flames routed through the chamber:

heatkit.com/docs/ov-fr01.gif

that is a traditional French commercial oven. The picture is not too good.

In a white oven, the flames don't go through the baking chamber. Instead, they go around the outside, such as in the Spanish Llopis revoving hearth oven:
jllopis.com/IPSORE3.htm

On your oven, if I understand it correctly, you might want to open up the throat a bit at the back to the first baking chamber, and change the upper one so that the gases have to go to the front before they enter the upper chamber.

Also, you may want to control the air supply to the fire by reducing the opening.

Best ...... Norbert Senf