I asked about firebrick earlier but I'm starting a new post about the stove. I pulled the front off the stove and the combustors are cracked, I can more or less pull them apart with my fingers. I need a Combustor ACI-19N, I see several sites with them, have to do some more looking around for the best price. I'm getting the gaskets too, there are 2" and 3" wide gaskets, the CC is 2.5" deep. So do I get the 3" and trim it? And I want to order a thermo probe for it. There is a small phillips head screw that comes out for the probe on the front of the stove. It looks like it's supposed to stick right inside the combustor. Is that right? The manual doesn't mention them, so how do I pick the right one? There's 8 of them here, they don't say how long the probe is. https://www.woodmanspartsplus.com/Wood--Coal-Parts/Catalytics/Thermo-Probes/D66550.html
Catalytic Combustor for Appalachian 32-BW after 1989
- Thread starter Orerockon
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Link for a catalyst vendor was provided in the firebrick thread
www.hearth.com
Adding firebrick questions
OK so I have a rather long story. I have an early 2000s Appalachian 32-BW and I got sick of the firebrick breaking and falling down. So I went online and got some USC "ceramic materials" bricks. It's not as dense as the original brick, kinda sandy and lighter than the old bricks which look like...
www.hearth.com
Right, btu they have 2 magnetic thermometers which I assume just plop on the top of the stove. The link I gave was to another site that had a bunch of them listed. How do I know which one to get?
What? The link is about combustors!
midwesthearth.com
Catalytic Combustor Appalachian (2.5
Midwest Hearth MH-19N replacement combustors are a high-quality choice for your catalytic wood burning stove.Replacing your old combustor will help you improve your stove's efficiency, saving you money and producing less pollution. split Catalytic Combustor FAQ Catalytic Combustor Warranty...
midwesthearth.com
Yeah but I'm asking about what thermo probe will work. The link I gave has the most I can find in one place.What? The link is about combustors!
Catalytic Combustor Appalachian (2.5
Midwest Hearth MH-19N replacement combustors are a high-quality choice for your catalytic wood burning stove.Replacing your old combustor will help you improve your stove's efficiency, saving you money and producing less pollution. split Catalytic Combustor FAQ Catalytic Combustor Warranty...
So I got what I thought I needed to change out the combustors. However the gasket material that the site I ordered from said was the right stuff is obviously not. What type of gasket do I have? And if I can piece it together is there any reason why I couldn't just put it back in?
PS the combustors came out in little pieces and powder so I think they were due for replacement a few years back. Think I bought it 13 years ago.
![[Hearth.com] Catalytic Combustor for Appalachian 32-BW after 1989](https://www.hearth.com/talk/attachments/20201215_120751-1-webp.269395/ "[Hearth.com] Catalytic Combustor for Appalachian 32-BW after 1989")
![[Hearth.com] Catalytic Combustor for Appalachian 32-BW after 1989](https://www.hearth.com/talk/data/attachments/269/269422-8a3ab187b96135d1ce91bab2cc54ad7b.jpg?hash=JMc-8XTJ9I "[Hearth.com] Catalytic Combustor for Appalachian 32-BW after 1989")
PS the combustors came out in little pieces and powder so I think they were due for replacement a few years back. Think I bought it 13 years ago.
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Also I found this on Fire Cat's website http://www.firecatcombustors.com/Articles.asp?ID=250#Monitor. It was incredibly helpful. I made a pdf of it to print out and nail to the mantelpiece :D
That should work, I do believe that is expanding gasket, once it gets hot it seals up around the cat. Most use masking tape to hold it on.
Yup that gasket will expand outward and create a tight seal, make sure there are no remnants stuck to the stove where that cat sits in, use masking tape to hold the gasket on place on the cat.
Well the gasket they sold me didn't expand far enough, thankfully I saved the extra and adding that seemed to work. It gets up to over 1000 deg. if I wait to get to 500 before closing the damper bypass. So I assume it's working. The Firecat page says "Don't hot fire your stove" because it can damage the combustor. What exactly is hot firing? If I just build a normal fire it never gets to 500 without adding more wood. After adding wood 2 or 3 times it finally gets to 500. If I add enough wood to fill the box and leave the controls all open it will eventually get there. Then almost 90 minutes in, I can finally close the bypass. Is this normal? Can I just fill the box, leave everything open and wait for it to get to 500? I'm using dry as a popcorn fart maple. FWIW I'm using a Condar thermo probe 1/2" from the surface of the combustor.
From Blaze King:
Burn natural wood only. Do not burn trash, garbage, artificial or paper logs, gift wrappings, coal, lighter fluids, chemical starters, treated or painted wood, driftwood or chemical cleaners. These may contain chemicals that could de-activate the catalyst.
Catalytic combustor temperatures above 1800F (1000C) will shorten the life of a combustor. Combustor temperatures between 1400F and 1600F (760C – 870C) are common, but operating temperatures between 700F and 1400F (371C – 760C) are recommended.
Full catalytic operation occurs at catalytic combustor temperatures above
700F (371C). Combustor glowing only occurs at temperatures above 1000F (538C). With aged combustors, there will be less glowing, but as long as the combustor reaches light-off temperature of 500-700F (260-371C) catalytic operation is very effective.
THE COMBUSTOR DOES NOT HAVE TO BE GLOWING TO BE OPERATING EFFICIENTLY.
To prevent damage to your combustor:
DO NOT drop the combustor.
DO NOT Run water through the combustor
DO NOT Remove the metal band from the combustor.
DO NOT Scrape the inside walls of the combustor.
Never scrape the combustor with any hard tool, pipe cleaner or brush.
DO NOT Use compressed air to clean the combustor.
Limit cleaning to the face of the combustor.
NOTE: Never remove a combustor without
approved combustor gasket in hand as original gasket will fall apart when removed from appliance.
Remember to re-install the Flame Shield (the perforated plate) in same position it was found.
TIP: A hot fire will usually prove to be the best method of cleaning the combustor of deposits.
Burn natural wood only. Do not burn trash, garbage, artificial or paper logs, gift wrappings, coal, lighter fluids, chemical starters, treated or painted wood, driftwood or chemical cleaners. These may contain chemicals that could de-activate the catalyst.
Catalytic combustor temperatures above 1800F (1000C) will shorten the life of a combustor. Combustor temperatures between 1400F and 1600F (760C – 870C) are common, but operating temperatures between 700F and 1400F (371C – 760C) are recommended.
Full catalytic operation occurs at catalytic combustor temperatures above
700F (371C). Combustor glowing only occurs at temperatures above 1000F (538C). With aged combustors, there will be less glowing, but as long as the combustor reaches light-off temperature of 500-700F (260-371C) catalytic operation is very effective.
THE COMBUSTOR DOES NOT HAVE TO BE GLOWING TO BE OPERATING EFFICIENTLY.
To prevent damage to your combustor:
DO NOT drop the combustor.
DO NOT Run water through the combustor
DO NOT Remove the metal band from the combustor.
DO NOT Scrape the inside walls of the combustor.
Never scrape the combustor with any hard tool, pipe cleaner or brush.
DO NOT Use compressed air to clean the combustor.
Limit cleaning to the face of the combustor.
NOTE: Never remove a combustor without
approved combustor gasket in hand as original gasket will fall apart when removed from appliance.
Remember to re-install the Flame Shield (the perforated plate) in same position it was found.
TIP: A hot fire will usually prove to be the best method of cleaning the combustor of deposits.
OK so one more question. After it's been at combustor temp for quite a while, I'll suddenly smell smoke but there isn't anything visible coming from the stove. All vents and the bypass are closed. Whether the air control is cracked open or fully closed deosn't seem to matter. It's only happened a few times so far. Is this back puffing? I read Firecat's site and this is what it has to say:
When the combustor has an exhaust temperature over 1400° F. (760° C.) it can act like a glow plug (spontaneous combustion igniter).
Usually the wood gas-to air mixture is either too lean or rich to form a highly flammable mixture. There are times when this mixture is just right within the firebox during the normal burning process. If the combustor is running at or above the ignition temperature of the mixture, spontaneous combustion will result, causing the stove to vent puffs of smoke.
I's consistently been running over 1000 but only near 1400 a couple times. Could there be another reason? It never did this before I put in the new combustors. It is definitely not airtight, there are tiny little gaps in the door between the metal and the glass.
When the combustor has an exhaust temperature over 1400° F. (760° C.) it can act like a glow plug (spontaneous combustion igniter).
Usually the wood gas-to air mixture is either too lean or rich to form a highly flammable mixture. There are times when this mixture is just right within the firebox during the normal burning process. If the combustor is running at or above the ignition temperature of the mixture, spontaneous combustion will result, causing the stove to vent puffs of smoke.
I's consistently been running over 1000 but only near 1400 a couple times. Could there be another reason? It never did this before I put in the new combustors. It is definitely not airtight, there are tiny little gaps in the door between the metal and the glass.
It can do it on a smaller scale, you will only hear a slight woof sound and tiny bits of smoke will come out the air controls usually on your model stove. I would always try to keep a small active flame in my old Appalachian due to this.
I'm sure this is what it's doing! I will try it, after actually operating it correctly for a month or so I found out that it requires a lot more attention than I can usually give it. Heck I didn't even know that I could get it up to 500 F in less than than an hour and I think I'm still not doing it right. It did take me a little while to get it down, I sat in my den office (I'm 12 feet from the stove) freezing my butt off 2 hours every morning for 20 years. I work in my shop half a day when I'm really busy with selling rocks and my wife works in her office in the house but she is not woodstove savvy and doesn't want to learn 
I paid little attention when I had half time consulting work, now due to the Rona I find myself with no work and not much hope to get any. Honestly before I found this forum I had little interest in how to "do it right" with actually using the combustor correctly. Not that I didn't have the instructions stapled to the manual, I put it in a folder and forgot about it.
I paid little attention when I had half time consulting work, now due to the Rona I find myself with no work and not much hope to get any. Honestly before I found this forum I had little interest in how to "do it right" with actually using the combustor correctly. Not that I didn't have the instructions stapled to the manual, I put it in a folder and forgot about it.While I'm at it is there a rule of thumb about how hot you run the combustor? My new temp probe as the "operating range" marked as 500-approximately 1700 and I've only got it close to the upper end the first time I tried to do it. It scared me so I don't run it that hot now. I'm thinking in terms of efficiency, as in heat output for a given amount of wood. Generally I've been running it halfway between on the probe, about 1100 F. I'm definitely going through more wood than I used to but obviously the heat output is higher than before. Good thing I started the season with 4 cords in the barn :D
A new cat will burn at higher temps, just keep an eye on it, mine liked to burn around 1200-1500 once it settled down at the beginning of the wood burning cycle with all the wood off gassing.
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