I fired up the kiln with the heat exchanger assembled. The results were mixed. After 18 hrs of firing, the cone was at about cone 04 and having a tough time getting any hotter. It seemed like the airflow just was not powerful enough to provide enough oxygen to keep the temperature climbing.
On some levels, the heat exchanger worked well. The exhaust from the kiln was cooled to the point that you could hold your hand about 4 inches over the top of the chimney indefinitely. The air entering the kiln from the heat exchanger was heated to the point where it was just a little cooler than the smoke leaving the chimney.
It was disappointing that the kiln stalled out at cone 04, and it seemed like all the signs were pointing to an inadequate airflow.
I decided to take out the primary heat exchanger entirely and try it with just the secondary heat exchanger. The secondary heat exchanger was a set of 24 one-inch pipes that rests on the first layer of ceramic pipes. Smoke enters the ceramic pipes via holes in the pipes, and then exits the chimney via the stainless steel pipes.
I rebuilt the chimney and decided to test the kiln again.
