Hi Folks,
I have sauna stove that we made from a new round boiler body 35" long 20" wide.
Fed from the outside.
The vertical pipe is 8" wide. 16 feet high.
The connector (stove to vertical)is about five and a half feet set at 30%.
The problem is constant back puffing. Unless the intake is cut to almost nothing (quarter inch or less) it back puffs.
Even after it's warmed up and the air inlet is closed to about a quarter inch, when I try to increase the fire by opening the draft another less than quarter inch it starts to puff again.
Opening the door a crack stops it but opening the draft increases it.
When the door is then closed it puffs unles inlet is closed almost to nothing.
Outside weather temp is about 75 degrees.
No outside wind.
When it's running and the draft is open a tiny bit (quarter inch) it's ok.
But starting it up is a real process with constant puffing. Then adding wood later or trying to make it hotter in the middle makes it constantly whuff untill it's back to a quarter inch open.
Round screw in air draft intake is about 3.5".
Before this I had a handmade square stove box that was about 75% of the size connected to a 6" wide 4 meter vertical pipe and it never back puffed. It had the same five and a half foot connector.
The galvanized piece covering the pipe as it exits the wall is for safety. (falling pine needles).
The metal part opposite the damper on the stove is just a stability support and has no other function.
This is making us crazy trying to figure out what the problem may be.
Before we changed the verical stove pipe going up it was 6" wide so we figured if we enlarged the pipe to the size on the stove 8" it would take care of the problem, The old upright pipe was 4 meters high.
The old stove rusted out so we thought of using a new boiler body to avoid the rusting out of the welds on a square stove.
Maybe the combustion chamber is too big? Inlet too big?Inlet shape?
I hope I have the images in the right place..The first image is the inside of the stove. The picture didn't get rotated and is on it's side.
Any suggestions would really be appreciated.
Thanks in advance,
micah