After three years of burning with only annual cleanings of the flue and door adjustements I have noticed that the stove, with its original ceramic cat, was almost constantly emitting a stream of blue smoke. Especially bad during the first 3-5 hours of the cycle. This is not normal and in this age of burn bans and green energy I wanted to attain that clean burn that cat stoves are supposed to be very good at.
I test my wood and it is softwood over two years old and moisture below 13%.
So I managed to acquire a SS cat element. The steel cats are what is now OEM on most stoves and is supposed to go active at much lower temperatures to start eating smoke sooner. It also has a ton more surface area which to me means more catalyst in contact with the smoke so it should do better at eating it. They are more resistant to thermal shock and the only drawback I could find is slightly higher cost and a higher likelihood of clogging due to ash. Honestly, I have never had anything accumulate in my cat, I think the BK design prevents this issue.
In preparation for the swap I used a sooteater brush system on my all vertical 12 foot flue which is over 4 feet of double wall and 8 feet of class A. I discovered that you can reach into the bypass hole and lift the bypass plate to expose the trough behind the cat and vacuum every dang bit of flue debris without wasting time and effort removing the flue from the stove. Try it, you can lift up that bypass plate towards the stove top and reach a finger in there to touch the back of the cat.
I was a little afraid of prying the cat out. The new one comes with an expanding gasket that might make the old one a tight fit. Manual says to pry out with screwdriver so that's what I did. It pried right out a little at a time on opposite corners. It was stuck in there but easily came out. No popping loose, very slow. The ceramic cat looked fine with cracks and held together nicely. It's a fairly stout piece. The back of the cat had weird aluminum foil looking shrapnel peeling off of it. Hmmmm, maybe I was loosing catalyst from the substrate. Oh and with the cat out of the way I could double check that all debris is vacuumed from the cat chamber, it was.
The new cat comes with new gasket which is wrapped with masking tape to hold it on. The steel cats also come with masking tape across the face and back of the cat which I cut off. It is important to leave the perimeter tape in place since shoving the new cat in requires the new gasket to be firmly held in place. The new cat was a tight fit. It is very important to evenly push the cat into the frame or it could bind. Slow and even working all around. That's it. Start a fire.
This cat works differently. My old cat got plenty hot and was still glowing but it was just letting smoke by. The steelcat is dark until you flop the bypass and then it instantly begins to glow orange. It was odd, closing the bypass actually caused the fire to pick up and burn more briskly. Perhaps the cat burning actually increased draft? It's pretty warm here so I wasn't able to burn a full load but I can say that within 30 minutes of lighting the fire that the emissions would have passed the 20% burn ban smoke opacity test which would NOT have happened with the old ceramic cat. It was still evident that I was burning but within the first hour, and after turning down the thermostat, the emissions were clear.
Main reason for this thread was to show that changing cats is REALLY easy with simple hand tools and not very expensive when you consider the benefits of a cat. Second is to show some of the differences between a steel and ceramic cat.
I test my wood and it is softwood over two years old and moisture below 13%.
So I managed to acquire a SS cat element. The steel cats are what is now OEM on most stoves and is supposed to go active at much lower temperatures to start eating smoke sooner. It also has a ton more surface area which to me means more catalyst in contact with the smoke so it should do better at eating it. They are more resistant to thermal shock and the only drawback I could find is slightly higher cost and a higher likelihood of clogging due to ash. Honestly, I have never had anything accumulate in my cat, I think the BK design prevents this issue.
In preparation for the swap I used a sooteater brush system on my all vertical 12 foot flue which is over 4 feet of double wall and 8 feet of class A. I discovered that you can reach into the bypass hole and lift the bypass plate to expose the trough behind the cat and vacuum every dang bit of flue debris without wasting time and effort removing the flue from the stove. Try it, you can lift up that bypass plate towards the stove top and reach a finger in there to touch the back of the cat.
I was a little afraid of prying the cat out. The new one comes with an expanding gasket that might make the old one a tight fit. Manual says to pry out with screwdriver so that's what I did. It pried right out a little at a time on opposite corners. It was stuck in there but easily came out. No popping loose, very slow. The ceramic cat looked fine with cracks and held together nicely. It's a fairly stout piece. The back of the cat had weird aluminum foil looking shrapnel peeling off of it. Hmmmm, maybe I was loosing catalyst from the substrate. Oh and with the cat out of the way I could double check that all debris is vacuumed from the cat chamber, it was.
The new cat comes with new gasket which is wrapped with masking tape to hold it on. The steel cats also come with masking tape across the face and back of the cat which I cut off. It is important to leave the perimeter tape in place since shoving the new cat in requires the new gasket to be firmly held in place. The new cat was a tight fit. It is very important to evenly push the cat into the frame or it could bind. Slow and even working all around. That's it. Start a fire.
This cat works differently. My old cat got plenty hot and was still glowing but it was just letting smoke by. The steelcat is dark until you flop the bypass and then it instantly begins to glow orange. It was odd, closing the bypass actually caused the fire to pick up and burn more briskly. Perhaps the cat burning actually increased draft? It's pretty warm here so I wasn't able to burn a full load but I can say that within 30 minutes of lighting the fire that the emissions would have passed the 20% burn ban smoke opacity test which would NOT have happened with the old ceramic cat. It was still evident that I was burning but within the first hour, and after turning down the thermostat, the emissions were clear.
Main reason for this thread was to show that changing cats is REALLY easy with simple hand tools and not very expensive when you consider the benefits of a cat. Second is to show some of the differences between a steel and ceramic cat.
