This is a guide for safe use of our outside feed Blueberry stove. Our stoves are safe if used properly. Never leave a fire unattended and don't use normal firewood, as larger logs will burn long after your need for heat is done and can cause overheating after you are done with your sauna.
 
  Of course you want them hot and you want the sauna hot fairly fast. To build a fire fast, a full firebox of dry small wood ignited with paper is the best way. Air is the important element and the best way to control the intensity of the fire, open the draft wide.  
 
  Arrange your kindling over some shredded newspaper with plenty of spaces for air to mix with the fuel. The only air supply is through the open door or the draft control in the door. There is no damper in the stove pipe for good reason- A damper in the exit pipe of the stove will back up the heat into the feed throat. This is an area that passes through the wall, and I want cool incoming air here to reduce accidental wall combustion. Never add a damper to the chimney.

When building a fire fast you will find a slightly open door works best. This is only okay if you are right there. Please, if you walk away, close and latch the door, using the draft control in the center of the door.   This draft control can be used in the wide open position for building a fire, but after the sauna is hot enough for your taste, refill the firebox , again with smaller try wood, and slide draft in to near closed. Keeping it open about a 1/4 inch will keep your fire burning at steady rate. If a second group will be using the sauna, just refill then firebox before use.

  Burning your fire too big , with too much air, will actually cool off your hot room, as the hottest part of the flame is near the top. If you have fire coming out your chimney, you will not have anymore heat inside the sauna, and you are sucking in cool air to feed the big flame.