Post
by Sunny Boy » Sun. Nov. 22, 2015 10:34 am
My house had one. Only thing that was left of it is the brick hearth it sat on, and the brick ring that lined up under the sheet metal jacket, the slate covered, brick sided, dirt trench leading to that outer ring of bricks, and the large round ducts leading to all the floor registers, now tied into the oil furnace.
Like Don said, it was centrally located in the basement.
The hot air ducts are 8 inch galvanized pipe. The first floor cold air return ducts are just the bays between floor joists, closed off on the underside by galvanized sheet metal nailed to the joists. That lead to the front of the house where they was a wooden "Y" trunk built onto the front wall of the basement. One branch of the Y enclosed a basement window that could be opened to allow fresh air into the cold air return. The other branch lead to a very large floor register by the front door, near the base of the front stairs.
Helping a friend looking to move, one house we looked at still had the octopus furnace. As Don said, there's a jacket surrounding the cast iron coal furnace made up of galvanized sheet metal panels covering all but the front casting with the loading doors. The sheet metal panels just attach to a steel framework suspended around the stove. They were fastened so they could be easily removed to get at the enclosed parts.
Really, just a large cast iron stove with an enclosed air space. Cold air ducts leading into the bottom, hot air ducts leading out the top.
With mine, all the round hot air ducts in the basement have a simple sheet metal MPD type damper to help adjust/balance the hot air flow to each room.
Looking at the size of the brick hearth and outer brick ring, it looks like the furnace that was here was no larger than others I've seen in average sized houses. But, this house is a 4000 sq ft two story, uninsulated Victorian.
I'm guessing the furnace was meant to only carry some of the heat load, because the basement coal hot water heater was still here with the thimble for it to the chimney closed off. Above that, in the same chimney, the thimble for a kitchen range was closed off. And I found part of a coal parlor stove buried in a trash pit by my barn.
Paul
Anyway,back to the coal furnace,i see no reason why one of those centrally located in a mostly squarish house would not do the job just fine. 
