Catalytic combustor degradation?
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This came up on the BK thread a while back. It seems like many folks who had been running there stoves a few years had some cracks or pieces missing from there cat. This was presumed to be from the need in cold weather to reload while the cat was still active.
I have been following you guys from BK when I do my extension most likely a BK thanks to you guys. What do you guys do when you reload in cold weather?
I can't speak for everyone but I think many said they would open the bypass for a few minutes to cool the cat as much as possible before reloading. Then have the new load ready to minimize the amount of time the loading door was actualy open.
This came up in the Fall and I had just gotten my stove at the time so I didn't really get the need then. I do now
When it is truely cold and heating demand is high the cat will stay active long after a reload is needed.
This came up in the Fall and I had just gotten my stove at the time so I didn't really get the need then. I do now
When it is truely cold and heating demand is high the cat will stay active long after a reload is needed.
That's pretty much what I do but if I've got a steel cat in there I don't worry about thermal shock. I always try to avoid pouring a lot of flame heat to the cat when the bypass is closed, ceramic or steel. These cat stoves seem to like to idle along, so that's generally how I try to run 'em.
Woody, do you like the steel cat over ceramic.
With the design of the BK I find it hard (impossible) to avoid flame impingement.
When you close the bypass the thermometer drops about 50 degrees for about 1 min them goes up is that normal?
robbydanilow
Member
Noticed flaking on the downstream end of the cat on my fireview. Pieces on the periphery seem to be most impacted. Also some green haze. Odd but it works well on year 2
When you look at the "normal" used cats as shown on the manufacturer's websites they always seem to have a piece or two missing. I propose that it is normal to have little pieces fall out. I have one tiny chip in the middle of my cat after almost three years.
samfatboy
Member
I have had my Appalachian 52 Bay for 7 years now, still on the original cats. I actually had to replace the cat housing because of an overheat situation that melted the original cast iron housing. The new housing is 5/16 plate steel - was a bear to get installed. I thought for sure I needed to replace the cats, but they seem to be working okay - especially after I insulated the liner and installed the damper cut-off. I get regular 10 hour burns for 6 eco bricks, and up to 15 hour burns with 3/4 full firebox - about 12 eco bricks. I also got a cat thermometer which has really helped me dial in my start-up cycle. Thanks to all the tips I got from Hearth.com, during this record cold February here in CT, my house has had record winter highs.
They both work well. I have the old "diesel foil" steel cat, and have seen them shrivel from excessive heat in others' stoves. They held up OK for me; I babied them a bit and didn't run a lot of flame heat into them. The one in the Fireview I sold my BIL is doing OK in its fourth year, but had some slight distortion when I looked at it recently. The new Durafoil is supposed to be an improvement. Don't know if these are available for the BKs.
Now I let the cat cool by opening the bypass put a full load and let cat temp go up. When temp goes up to about 700 I close the bypass and the cat starts to glow instantly. Is that bad? Can I have problem with thermal shock, to much heat to fast?
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Thermal shock comes from moisture off gassing in the wood, that is why you want to burn dry wood in a cat stove.
Moisture + Hot cat = cracking
Throwing snow covered wood into a hot stove and closing the bypass is one way to kill a cat quickly.
I close my bypass when the cat is around 600-700, that should be fine.
Moisture + Hot cat = cracking
Throwing snow covered wood into a hot stove and closing the bypass is one way to kill a cat quickly.
I close my bypass when the cat is around 600-700, that should be fine.
I have had my Appalachian 52 Bay for 7 years now, still on the original cats. I actually had to replace the cat housing because of an overheat situation that melted the original cast iron housing. The new housing is 5/16 plate steel - was a bear to get installed. I thought for sure I needed to replace the cats, but they seem to be working okay - especially after I insulated the liner and installed the damper cut-off. I get regular 10 hour burns for 6 eco bricks, and up to 15 hour burns with 3/4 full firebox - about 12 eco bricks. I also got a cat thermometer which has really helped me dial in my start-up cycle. Thanks to all the tips I got from Hearth.com, during this record cold February here in CT, my house has had record winter highs.
You must have an extremely well insulated home. I also have a 52 Bay and with the temperature in the single digits or below zero I have to run the furnace just to keep the house at 60 degrees. The stove just does not produce enough heat to adequately heat my poorly insulated 1950's house when it gets much below 25 degrees. My Cat cover has slightly warped but the entire cat housing seems to be fine. I have noticed front side of my Cats are cracking and a few pieces of ceramic have broken between a couple of cells after not even a full 2 years of use. Not sure if that qualifies under the Cat warranty but I assume there would have to be more crumbling.
I have that same issue, I could run it harder but I don't like eating through the wood, I let the heat pump pick up the slack. My cats are cracked, but that partiality is from when I was poking them trying to get a thermocouple to read temps from the front.
samfatboy
Member
My house was built in 1975, and I have added some insulation to the attic, and now use the window film insulation every winter, but I would not call my house 'extremely well insulated' by any stretch of the imagination. Prior to installing the 52 Bay, I was burning an average of 1000 to 1250 gallons of oil per year, keeping my house an average of about 63 degrees. After installation, oil burning dropped to 450 to 600 gallons, mostly consumed in the early morning hours, but keeping the house an average 70 degrees.
To balance out heat and get more heat to the bedrooms, this year I installed a pellet stove in the living room side of the house. My 52 Bay is on the extreme, non bedroom, family room end of my 2200 sq ft colonial home. So far this year I have burned about 75 gallons of oil, but mainly just to keep the furnace from being completely dormant all winter.
The 52 Bay does fine on its own when temperatures are above 30 degrees, but below 20 definitely needed some help from the furnace. The primary reason for adding the pellet stove was heat distribution. My family room would be 85 degrees, even with all kinds of fans blowing the hot air off the ceiling. Meanwhile the upstairs bedrooms on the other side of the house would be 60 degrees, okay for me but not my ex wife or my daughter. Now with the pellet stove in the living room, I put much less demand on the 52 Bay, and have a nice comfortable 70 throughout the whole house -- a little warmer in the family room and the living room.
A few suggestions,
1. Get an energy audit, and seal up draughty windows and corners - surprisingly corners can have a lot of leaks.
2. If you have old windows like me and cannot afford to replace them all, get the 3m window seal kits. I was amazed how much difference the window seal kits made - it was like I was just throwing heat out the windows.
3. If you haven't already, insulate your chimney liner, and install a damper block off. Same thing, it was like I was just throwing heat away out the chimney. When the fireplace would burn out on sub zero mornings, it was like someone left a door open at the fireplace. Since installing the liner insulation and damper block off, my family room and kitchen take a lot longer to lose heat once the fire burns out, and my burn times have increased by 25 to 30 percent.
As far as the cat is concerned, my guess would be that your cracks are caused by thermal shock from too rapid cooling. From what I can tell, the ceramic cats can handle extreme heat a lot better than they can handle fast cool downs. Mine withstood heat hot enough to melt cast iron, and I don't have any cracks or loose pieces. I am not sure about the catalyst coating, but since I am getting up to 14 hour burn times on a full stove, I am not all that concerned.
My 52 Bay will never be a Blaze King, but it is a decent stove for the money,
Sam, Thanks for the suggestions. I have made wood frames for the inside of 3 old aluminum picture windows and covered with clear plastic. It definitely helps. My liner is insulated and I have Roxul stuffed up the old fireplace damper. Roxul is also surrounding much of the stove. Not as good as what Mellow eventually did with his fireplace but I really don't believe I'm losing much heat to the chimney. I need to take IR temperature measurements on the outside of the chimney again but last time I did it there did not seem to be a large variation in the temperature of the brick. Just did not feel like pulling the insert out and putting cement board over the Roxul.
I think insulation is my biggest problem. I have 2 unused bedrooms closed off in the winter and spend much of my time on the first floor. When the temperature steadily drops below 25 the cold just overwhelms the stove. I am certain there is no insulation in the walls. Will look into an energy audit. If I could raise the downstairs temperature by about 4 to 6 degrees and not be a big investment I would be very happy. I live alone so I don't care if the house is not 70 degrees. However, I would like it a little bit warmer than 60 without using the gas furnace.
samfatboy
Member
I know it is a large initial investment, but a through the wall pellet stove installation in another end of the house will make a huge difference. It is super easy to do if you are at all mechanically/constructionally talented. I just hate paying for oil...
When I close the bypass the catalytic glow is very bright and I can see fire I front of it without flames hitting it. Is that normal?
blueguy
Feeling the Heat
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