Fixing Someone Else's Mistakes, Again

Just before the old furnace died in the spring, there was a substantial decrease in airflow from the shared vent serving Rudi's room and the guest bedroom. I thoroughly checked the ducting in the basement, could not find the problem, and then the furnace promptly quit. With the new furnace being installed and working perfectly, I began to look into the problem again. and found the problem, and a few other interesting things, including a live Loomex electrical cable that had been pulled up alongside the old heating vent, and run along the heated space to an electrical outlet close by!

Above Left: The floor opening located nearly directly above the first floor wall. The two grey pipes are the hot and cold supply lines for the hot water heating system installed sometime in the 'thirties possibly. The heat from the forced air furnace is directed up the wall - the black space, to the right under the floor, and then up a bit into the heating vent located at the gap in the baseboard.

Above Right: A closer view down the wall cavity, revealing another interesting thing. The round tube standing in the wall cavity must have been installed before the hot water supply pipes, meaning it is original to the construction of the house in 1888. From that time until the oil hot water system was put in place, the second floor was heated by this 'gravity' heating sysstem, with one feed serving two bedrooms at the front of the house, and another  feed serving two bedrooms at the back of the house.

When the house was converted to forced air natural gas heating in 1987, a 6" diameter flexible conduit duct was pulled up inside the original 8" diameter carbon steel duct, placed below the old water supply pipes, and then simply left in the space between the joists pointing toward the outlet vents. Over the years, the conduit must have popped out of place, slipped back into the vertical duct, and then simply blasted hot air against the floor and into the joist space running the length of the room, with a consequent significant reduction of airflow from the vents.

Above Left: The old cast iron hot and cold pipes are cut and removed, and the original 8" diameter duct has been pulled out. The reciprocating saw with metal cutting blade chewed through the pipes in under 5 seconds each. The circular saw was used to cut the floorboards, and the flashlight required to see down the inside of the wall.

Above Right: A  view down the wall cavity with the original duct removed. The two wooden studs are the left and right wall studs, making the wall about 10 inches wide. Unfortunately, the gap between the two is open to the inside surface of the exterior double brick wall, a probable significant source of heat loss, as all of the cold from the inside surface of the much of the front wall can pass into the house through this gap.