Johnson Mfg & Sales Inc.

Johnson Outdoor Wood Furnaces

N5499 County Rd E Ogdensburg, WI 54962
(920)244-7581 or (800)515-4328

Frequently Asked Questions

Q: How far can the unit be from my home?
A: The Johnson Furnace is designed to be outside of the home, away from the house.  The usual installation distance is between 50 & 200 feet.  An installation location greater than 200 feet from the area you are heating will reflect a loss of efficiency due to the great lengths the water travels.  If necessary, this may be compensated for by using a larger diameter copper pipe instead of the normal recommended 1" Kitec pipe.


Q: How can you claim to have 50% -80% less smoke than competitors?
A: Johnson stoves come standard with two blowers.  One is located on the ash door, the other on the firebox door.  The blower on the firebox door forces all smoke to the back of the stove.  In other stoves, this is where the smoke leaves through the chimney.  The removable baffle plate in our furnace covers the exit to the chimney and forces smoke to travel back to the front of the stove over the lip of the baffle plate and then to the back again and out the chimney.  These three passes allow gases more time to get burned creating less smoke and providing more heat from your wood!


Q. How does the furnace work?
A: The fire box is surrounded by water. When the water temperature in the furnace drops below the set temperature on the furnace, the air injection system automatically turns on. Air is then injected beneath the fire and across the top of the firebox to increase burn intensity. Waste materials(smoke and creosote) are burned as fuel rather than discarded smoke. Water tubes in the top of the fire box make up a water baffle to transfer more heat into the water. A bypass is opened up when loading wood to allow smoke to go up the chimney instead of escaping from the loading door.


Q. How difficult is the stove to install?
A. The Johnson Stove is relatively easy to install by running two pipes between the furnace and the building to be heated. One pipe will be a supply of hot water to the building to be heated, the other will be a return pipe, carrying cooled water away from the building. KITEC pipe is strongly recommended and has proved to be extremely durable in cold weather conditions. The KITEC pipe should be enclosed in insulation and then housed in PVC pipe for best results. The pipes must be installed at least 24" underground, and 4'-5' if they will be placed where heavy vehicles or machinery will drive over them.


Q. What are the benefits of a Johnson Stove?
A. The Johnson Stove offers the following benefits
*Up to 80% less smoke
*Clean burn give more heat for less wood
*No more unburned coals
*Wood to gas- gas to heat
*There is none to compare


Q. What is an Internal Combustor?
A. This totally new technology is so far advanced that it makes even the best of grates and ash removal systems obsolete. This new concept is so more efficient than other designs it's like putting a supercharger in a furnace. Our Johnson with the Internal Combustor burns its fuel so completely, that the job of removing ash is no longer a task. No more unburned coals as seen on energy wasting units, with grates side draft or the draft in the door. Our design is to mix the oxygen with the fuel so the coals are allowed to burn to very few ashes for maximum BTU and easy ash removal.


Q. How does the Little John and Big John work?
A. The firebox is surrounded by water. When the temperature in the furnace drops below the set temperature on the furnace the air injection system starts. Air is then injected under the fire and also into the firebox near the top to increase the burn intensity. By mixing the top air with the combustible gases, smoke creosote is burned as fuel, which would otherwise go out the flue. Water tubes in the top of the firebox make up a water baffle that is used to transfer more heat into the water. A bypass is opened up when loading wood, to let the smoke go out the flue. The fire box is of round design which means fewer welds, and more strength. This puts the Johnson in a New Generation of Wood Heat!


Q. What are your furnaces features?
A. Our furnaces have:
*Extra large loading door
*Large firebox
*All controls in one handy location
*Light for night loading
*Smoke bypass for easy loading
*Hookup to multiple buildings
*Lockable fire door
*Anti-flashback door safety catch
*Shutoff switch for blower
*Easy ash removal-no grates, augers, or ash pans
*Quick temperature recovery time
*All parts are precision made
*Weather proof house design
*100% airtight insulation
*Powder coated paint
*Up to 80% less smoke
*12 year prorated warranty
*PROUDLY MADE IN THE U.S.A.