I have had a Hutch stove for about 5 years. I bought it on Ebay. Although it was several years old, I believe (from its condition) that it was unused. The first season I tried using the catalyst function as best I knew how: 1. Get stove up to temperature 2. Close down air supply 3. Use the lever to move the plate over back smoke pipe hole so flue gasses are forced through catalyst. 4. I was burning seasoned oak or hedge (bois d' arc). Although the flames looked neat and I do think it put off more heat, I had issues: 1. Fire wanted to cool off too fast. 2. Occasionally a "POOOMP" sound, with a puff of smoke from the air tube. The "POOOMP" sound was pretty alarming, and kind of a deal breaker for me. I have burned it for years without worrying about the catalyst function, with good success. Today I was looking at the air tube, located above the door, about 2 inches from the front of the stove. I use it for a port for a thermometer. I noticed that it has 15 or so little ports to inject air directly in front of the catalyst. With the air ports, I wonder if I am getting a "true" combustion temperature or a lower reading. My question: Can I block off this air tube to avoid getting any "extra" uncontrolled air? I was thinking of using a piece of all thread with copper sealing washers. Thanks for your help.