Chimney
From Cornburning
When you are planning your chimney layout there are a couple of things to keep in mind.
Keep the distance from furnace to vertical flue as short as possible. The rule of thumb is 15 feet max. and elbows count as 10 feet, 45's count as 5 feet, so this length runs out very quickly. This rule of thumb is true for all solid fuel burning appliances not just corn.
When you install the pipe from the furnace to the chimney make sure the crimped end is "down", or toward the furnace. This is correct for any flue pipe for two reasons, it keeps any fly-ash in the pipe, and most of, all any condensation will stay in the pipe as it runs downhill. If you don't do this the furnace will work fine, but you may get some black water dripping from the joints when the furnace is on idle and condensation forms.
For re-lining brick chimneys you can get away with using Single wall stainless 6". Single wall stainless costs about $13 a foot for straight pipe, $35 for elbows. It must be stainless because anything else with corrode very rapidly and create a very dangerous condition.
For living space installations, you need to think about double wall insulated stainless which is much more expensive.
The second think you need to keep in mind is that exhaust from a corn stove is extremely corosive. You must use AL29-4C grade stainless steel chimney. AL 29-4C stainless steel is a superferritic stainless steel designed for extreme resistance to chloride ion pitting, crevice corrosion and stress corrosion cracking.
Other grades of stainless, and other types of chimney, such as galvanized, are not the same. Even 316Ti, which is similar to Grade 316L except that 316Ti has better high temperature strength, and mechanical strength. Used for equipment exposed to aggressive corrosive conditions and high temperature applications,including automotive flexible connectors, welded bellows, chimney liners, and flexible ducting. Which all sounds like it should handle our corn burning application, can not.
