Home-Built Furnace Burns 8-Ft. Logs

Home-Built Furnace Burns 8-Ft. Logs WOODLOT EQUIPMENT Miscellaneous 25-1-33 George Lumax, Swan River, Manitoba, has heated houses and farm buildings with wood-fired boilers since the early 1990's, but was never really satisfied with the commercial furnaces he could buy. The problem was that he kept heating more and more buildings with a couple of outside wood stoves. A local logger provided 8-ft. logs which they would then cut into 4-ft. lengths to fit into the furnaces. Lumax decided they needed a "whole log" furnace that could handle the big 8-footers but he couldn't find anything on the market. He decided to build one from scratch. The furnace he built is 10 ft. long, by 4 ft. square. To make it, Lumax started with 3 by 3-in. square tubing for the framework. He then welded 3/16-in. thick steel plating inside and outside the frame to form the firebox. Inside the burning chamber, he added vertical 3/8 by 2-in. flat steel bars, to keep the wood away from the steel walls. The 3-in. space between the inside and outside plates serves as the waterjacket for the boiler. To allow water to circulate properly, he drilled holes in the 3 by 3 frame before welding on the plating. The stove is located next to Lumax's garage, which houses a 150-gal. reservoir for the boiler. The entire system, including reservoir and lines to the buildings and radiators, contains about 600 gal. of a 70-30 water-antifreeze mixture. A wall inside the reservoir assures that cool water coming back in from the various buildings is not mixed with already-heated water. Cool water from the reservoir is pumped into the bottom of the water jacket where it travels up the sides of the firebox and across the top of the furnace. Then it goes into the burning chamber through a grid of 2 by 6 steel tubing, which he used to make a grate for the logs to sit on in the stove. From there, the heated water travels to the reservoir. He tries to maintain a steady 160-degrees F. hot water temperature in the boiler. Intake air to the stove is drawn from inside the garage, so it's preheated. He put 8 blower tubes into the firebox, so there's plenty of air for the fire. The fan for this simple air injection system was salvaged from an old air seeder. A separate pump for each heated building circulates water from the reservoir to the building, with flow regulated by thermostats in the building. Lumax says he uses 200 to 300 cords of wood each year. Feeding all those 8-ft. long logs into the furnace could be a problem if done by hand. He made it simple by adapting a conveyor from an old Farmhand stack mover to drop logs into the stove. The converted stacker holds up to three cords of wood. He added a hydraulic motor and controls to convey logs into the stove. He loads logs onto the conveyor with a log grapple on a tractor. The firebox has a cleanout at one end to remove ash. Lumax says the stove usually goes two weeks or more between clean-outs, and the total ash removed each time is not enough to completely fill a skid-steer bucket. All temperature controls, water pumps, blower, and hydraulic pump and reservoir are located in the garage near the water reservoir. "This keeps all the equipment out of the weather," Lumax says. In total, the boiler provides heat for four houses, a bunkhouse, the garage, a 40 by 100-ft. shop, a 35 by 85-ft. shop, an office, and an indoor swimming pool. Contact: FARM SHOW Followup, George Lumax, Box 935, Swan River, Manitoba, Canada R0l 1Z0 (ph 204 525-4991; E-mail: pongo@mb.sympatico.ca.).

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