Rocket Stove troubleshooting

We have made a rocket stove with firebricks, regular bricks, a cut off air tank, chimney flue and triple wall stainless steel stove pipe and cob. We lit it up almost immediately after build and it was drawing and making fire just fine.

It works - gets 1000 degrees at top of tank, takes fuel every 2 hrs.

Question - why are we using so much fuel?
And, is this getting hot enough?


Pictures below.




This is a temporary stove and we are just running some tests, but really want to know how we should adjust to make our final one which will be a cook stove as well as mass heater.

Thank you in advance [size=18] for all your input![/size]

sarah miller wrote:[size=18]We have made a rocket stove with firebricks, regular bricks, a cut off air tank, chimney flue and triple wall stainless steel stove pipe and cob. We lit it up almost immediately after build and it was drawing and making fire just fine.

Triple wall? In the cob (won't let the heat get to the cob)? Or just as the riser (will work but burn out as the heat will burn the SS because it gets hotter than metal can stand)?

Do you have sufficient BTU's to do a cook stove and a mass heater? How many BTU's do you want to store? How many BTU's does it take to cook? These are things you should figure out before you design your final system.

These j-tube combustion systems are designed to run fast & hot. Otherwise, you are not burning efficiently. Every 2 hours doesn't sound frequent enough to me.

from the angle of your picture, your feed tube looks excessively long., and obviously i dont know the dimensions of the other parts of your furnace so maybe that has nothing to do with it.

its a nice looking set up tho thanks for sharing the pics.