I am new to burning a cat stove. I purchased a used Blaze King King EKJ-1101 and put a new cat in it and a new thermometer. I have burned it a couple of times and both times the cat temp went past 2000 deg. I know that I am supposed to try and keep the cat at 1700 deg or below. What causes a cat to burn so hot and how do you regulate it. I opened the bypass as instructed but that did not do too much. What did seem to happen both burns is that later in the burn cycle (1-2 hours into it) things seemed to settle down. There is not too much to adjust on the blaze king, except the temperature dial which I have had on low both times.
Cat running too hot
- Thread starter tdwolfe
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil. -
Super Cedar firestarters 30% discount Use code Hearth2024 Click here
- Status
How are the gaskets on the door? Could be leaking some extra air? How tall is the chimney, may need a pipe damper to slow her down?
I replaced the gasket yesterday and I have not had a chance to fire it again since. The temps are heading back down though and I will try it again. The chimney about 20 foot, exterior lined masonry with two 90 deg turns. I do not think it is too much draft.
The wood is last season's wood. And it has been stored inside. Maybe it is too dry?
The wood is last season's wood. And it has been stored inside. Maybe it is too dry?
I dont think its the wood to dry. Its never hurt me. How are you referencing the 2000F temp? Is when you have snuffed the fire right out and then it creeps up? @ first turndown there will be alot of extra smoke to feed the cat. Maybe you have turned it down to far to early? The area on the stove top above my cat will reach 750F or so for the 1st hour or 2. Other areas are at 500f or less then it evens out once the excess smoke is consumed.
Attachments
![[Hearth.com] Cat running too hot](/talk/data/attachments/19/19161-de89fe41e011e8783cd4e08050fdcdaa.jpg?hash=Z2BYYL_L6t)
![[Hearth.com] Cat running too hot](/talk/data/attachments/19/19162-fce051317343d67e4e6fba23109fbaf5.jpg?hash=c_2O4Tufz_)
Thanks North of 60. The 2000º temp is referenced from the probe that is inserted just above the cat. I have engaged the cat when the temp on the probe thermometer was 600º the first burn and 500º on the second burn. The flue temps were the same at that point (read from a magnetic thermometer about 10 inches above the stovetop). My probe thermometer that I purchased has a temperature scale on it so I know exactly what temp it reads as apposed to yours which only seems to have a good and bad zone. Is it possible that 2000º temps are "normal" at the beginning of the burn but without an actual temp scale you would never know exactly what temperature you have? I certainly did not mind the way the stove functioned, I just do not want to replace the $280 converter sooner that I have to. Especially because I involved in the cat learning curve.
A bit of info I didn't post on my initial post. The flue thermometer drops whenever the cat is engaged as I am told it should. It went from 500-600º steadily down to around 300º in the same 15 minute time period that the cat crept up from 500-600º to 2000º
A couple of other thoughts that are bouncing in my head since last night...
1. I know cats burn hotter at the beginning of their life cycle and cooler just before you replace them. Is it possible that temps around 2000º are normal but without a true temp scale you would not know what the temp is?
2. How does a bad door seal leaking air into the firebox cause the cat to go up? Wouldn't that cause the firebox to burn cleaner and therefore the cat temp to decrease?
A bit of info I didn't post on my initial post. The flue thermometer drops whenever the cat is engaged as I am told it should. It went from 500-600º steadily down to around 300º in the same 15 minute time period that the cat crept up from 500-600º to 2000º
A couple of other thoughts that are bouncing in my head since last night...
1. I know cats burn hotter at the beginning of their life cycle and cooler just before you replace them. Is it possible that temps around 2000º are normal but without a true temp scale you would not know what the temp is?
2. How does a bad door seal leaking air into the firebox cause the cat to go up? Wouldn't that cause the firebox to burn cleaner and therefore the cat temp to decrease?
A good thought, Todd. I did take the cover off the thermostat housing (it houses an air flap that works in conjunction with a bimetal coil) and just the opposite is the case. There is a screw that is too long which holds the thermostat in place that is keeping the air flap from opening more that 1/4 of an inch or about 15º rotation). It appears that it is meant to have 90º of rotation. I will be replacing that with a shorter screw today.
"I purchased a used Blaze King King EKJ-1101 and put a new cat in it and a new thermometer. I have burned it a couple of times and both times the cat temp went past 2000 deg."
I have owned 4 Blazekings (2 Kings, one Queen and currently a 1992 model Princess) in the last 17 years, and have had the same experience. It can be a bit alarming, especially if you have taken all the warnings to heart, but I have not had any catastrophic failures because of it. This is a common experience when first starting a fire, and usual when reloading.
Building small fires to minimize a hot combuster is not a solution, go ahead and load it up for a long burn. This stove works best when used for continuous, uniform heat. If you only use it to take the chill off, you may find it a bit quirky. I think the non-cat stoves with small fireboxes may be the best for that type of heating.
I get more concern from excessive stack temps than the combustor temp, which you might get by opening the combuster bypass to lower the cat temperature.
The stove tempurature itself should indicate that all is well, even though the cat is quite hot. Northof60's post #4 shows a photo that is an excellent proof of that.
Keep in mind, a low thermostat setting on a new fire or reload is making major smoke for the cat to handle, once the gasses are driven off and the wood is charcoaled, the cat will mellow out. A good load of wood works the cat less over the long run, rather than repeating the cycle with short fires.
I also get torqued thinking of the replacement cost on a new combuster, but the fact is they will not last forever. My experience with them is they are prime for about 4 seasons of constant heating, while they still work beyond that time, the stack will require cleaning more often (I usually brush the stack once a season, but truth be told, twice might be better, especially since I feed a steady diet of pine and pinon)
If you concern is getting a good service life from the combustor, heed the warnings on using nothing but natural firewood, and accept the fact that you will probobly replace it in 5 years. I bet the cost of wood saved with the smoke it burns will pay for a new one in less than 2 seasons. If you pay a sweep, a lot less time than that.
I have owned 4 Blazekings (2 Kings, one Queen and currently a 1992 model Princess) in the last 17 years, and have had the same experience. It can be a bit alarming, especially if you have taken all the warnings to heart, but I have not had any catastrophic failures because of it. This is a common experience when first starting a fire, and usual when reloading.
Building small fires to minimize a hot combuster is not a solution, go ahead and load it up for a long burn. This stove works best when used for continuous, uniform heat. If you only use it to take the chill off, you may find it a bit quirky. I think the non-cat stoves with small fireboxes may be the best for that type of heating.
I get more concern from excessive stack temps than the combustor temp, which you might get by opening the combuster bypass to lower the cat temperature.
The stove tempurature itself should indicate that all is well, even though the cat is quite hot. Northof60's post #4 shows a photo that is an excellent proof of that.
Keep in mind, a low thermostat setting on a new fire or reload is making major smoke for the cat to handle, once the gasses are driven off and the wood is charcoaled, the cat will mellow out. A good load of wood works the cat less over the long run, rather than repeating the cycle with short fires.
I also get torqued thinking of the replacement cost on a new combuster, but the fact is they will not last forever. My experience with them is they are prime for about 4 seasons of constant heating, while they still work beyond that time, the stack will require cleaning more often (I usually brush the stack once a season, but truth be told, twice might be better, especially since I feed a steady diet of pine and pinon)
If you concern is getting a good service life from the combustor, heed the warnings on using nothing but natural firewood, and accept the fact that you will probobly replace it in 5 years. I bet the cost of wood saved with the smoke it burns will pay for a new one in less than 2 seasons. If you pay a sweep, a lot less time than that.
tdwolfe said:
TD, I've burned wood for a few years now but have yet to see any wood that is too dry. Your wood is from last season. The wood we will burn this year is 6-7 years since split and stacked. It is not too dry either.
Stockcarver, I am thankful for your post and it gives me the insight in to the Blazeking that will allow me to re-fire without too much concerns. Of course my main concern is that I will trash the cat, so it is comforting to know you have had similar readings and are still getting 4-5 years our of your cat. At that rate the cat is only costing $55 a year, well worth it for a 82.5% efficiency. I burned a Carmor top-loading stove last year with probably a 35-40% efficiency and smoked through almost 7 cords of wood. I am hoping for closer to 3.5 cords, fewer trips to the woodpile and a much warmer house in the mornings.
Thanks for all of your replies. Here is the status of the latest Burn (which is still going):
After fixing the door gasket and freed the air intake door on the thermostat, I started a fire as I did the two times before. I engaged the cat at about 450º and it lit off and stayed within range (topping out at 1600º) the flue temp at 10" above the stove remained in the 300-400 range. I am not sure what caused the change but it seems to be burning well even after reloading.
A few more questions if you will indulge a novice:
1. If the cat is still engaged (i.e. still burning at 500ish or above) do I have to wait until stack temp is above 500 again? On the blaze king video from their website the guy just throws one large split in and shuts the door and keeps talking. I have not been waiting and it seems alright, but it appears some people caution that it might damage the cat.
2. While there is less smoke from the chimney than when my old stove was starting up or at a low burn, there is still smoke coming out, at least it smells like smoke. Is this normal? My impression from the videos and websites is that there should be nothing and that the smoke smell will not be there either. Is it possible smoke is getting by somewhere else? I did not replace the gasket on the bypass door but am willing to do so. Or, is there somewhere else I should be looking.
Thanks,
Todd
Blaze King KEJ-1101
Wood Delivered
Formerly Carmor top loading
After fixing the door gasket and freed the air intake door on the thermostat, I started a fire as I did the two times before. I engaged the cat at about 450º and it lit off and stayed within range (topping out at 1600º) the flue temp at 10" above the stove remained in the 300-400 range. I am not sure what caused the change but it seems to be burning well even after reloading.
A few more questions if you will indulge a novice:
1. If the cat is still engaged (i.e. still burning at 500ish or above) do I have to wait until stack temp is above 500 again? On the blaze king video from their website the guy just throws one large split in and shuts the door and keeps talking. I have not been waiting and it seems alright, but it appears some people caution that it might damage the cat.
2. While there is less smoke from the chimney than when my old stove was starting up or at a low burn, there is still smoke coming out, at least it smells like smoke. Is this normal? My impression from the videos and websites is that there should be nothing and that the smoke smell will not be there either. Is it possible smoke is getting by somewhere else? I did not replace the gasket on the bypass door but am willing to do so. Or, is there somewhere else I should be looking.
Thanks,
Todd
Blaze King KEJ-1101
Wood Delivered
Formerly Carmor top loading
1. If the cat is still engaged (i.e. still burning at 500ish or above) do I have to wait until stack temp is above 500 again? On the blaze king video from their website the guy just throws one large split in and shuts the door and keeps talking. I have not been waiting and it seems alright, but it appears some people caution that it might damage the cat.
Todd, I personally don't pay strict attention to the rules on my stove, and it still works just fine. I rarely open it just to load a single stick, that kind of defeats the purpose of this type of heater. It is intended to be LOADED up with wood, then left alone. 12 hours later, or whenever it tells you it is done digesting that load, LOAD it full again, etc. If I were burning quality hardwood instead of pine and pinon, it woold probobly be more like 18 or 20 hours between loads. Loading a stick at a time, or every 2 or 3 hours is not the technique for a BlazeKing.
The combusters on these stoves have been used for more than a couple decades, if they were as delicate as one might be lead to think (reading between the lines) I seriously doubt the technology would still exist. I think the moral of the story is that a stove equipt with a combustor does require slightly more thought than a non cat stove, but you are not required to sacrifice a chicken to it either. They are quite a bit tougher than you think.
2. While there is less smoke from the chimney than when my old stove was starting up or at a low burn, there is still smoke coming out, at least it smells like smoke. Is this normal? My impression from the videos and websites is that there should be nothing and that the smoke smell will not be there either. Is it possible smoke is getting by somewhere else? I did not replace the gasket on the bypass door but am willing to do so. Or, is there somewhere else I should be looking.
Some smoke is normal, as is the odor of burning wood, the cat combustor consumes burnables such as creosote and turns them into heat, I suppose there is a lot of gases that are not burnable, and that is probobly a lot of what you see as smoke. It should smell pleasant, smoke that has a lot of creosote is pretty rank and has a distinct smell
More important is the amount of creosote being deposited in the chimney, I still get some, but a couple brush strokes removes the majority of it, twice a year max. My chimney cap usually catches the worst of it, and I might knock that off once a month (fortunately my stack is easily accessable). When it gets really cold (below zero) it is not unusual to see icecycles hanging from the cap with smoke coming out of it. It is not a bad idea to replace gaskets, if you have the "flapper" style door on the bypass, they can tend to collect crud that might fall down the chimney, if so, clean the groove that the door nests in and replace the gasket. Some blaze kings have a sliding door that is self cleaning and requires no gasket. There usually is a gasket that seals the combustor itself, at least the square combustors, the round or oval combustors don't have one, or at least mine didn't
If you charge the stove fully (what can easily be fit in the box, about 20-25 pounds of dry pine, maybe 30 or so of dry hardwood, when you can't get that much in, then its time to remove some ashes) it will take 2-3 hours for the wood to gas off and begin to charcoal. At that point, you will most likely see little but heat waves off the chimney. Remember you are used to burning lots of wood, and reloading often. Now you have to relearn a new stove technology, and once you do, you will regret not having one of these years ago.
These stoves are intended for long, even heat. I sometimes go a couple weeks on one match, some folks up north only need one match for a winter. IF that is the type of wood heat you want, the blazeking has no peers that I know of.
Little loads of wood and short fires are best left to the stoves with small fireboxes and no cat.
Todd, I personally don't pay strict attention to the rules on my stove, and it still works just fine. I rarely open it just to load a single stick, that kind of defeats the purpose of this type of heater. It is intended to be LOADED up with wood, then left alone. 12 hours later, or whenever it tells you it is done digesting that load, LOAD it full again, etc. If I were burning quality hardwood instead of pine and pinon, it woold probobly be more like 18 or 20 hours between loads. Loading a stick at a time, or every 2 or 3 hours is not the technique for a BlazeKing.
The combusters on these stoves have been used for more than a couple decades, if they were as delicate as one might be lead to think (reading between the lines) I seriously doubt the technology would still exist. I think the moral of the story is that a stove equipt with a combustor does require slightly more thought than a non cat stove, but you are not required to sacrifice a chicken to it either. They are quite a bit tougher than you think.
2. While there is less smoke from the chimney than when my old stove was starting up or at a low burn, there is still smoke coming out, at least it smells like smoke. Is this normal? My impression from the videos and websites is that there should be nothing and that the smoke smell will not be there either. Is it possible smoke is getting by somewhere else? I did not replace the gasket on the bypass door but am willing to do so. Or, is there somewhere else I should be looking.
Some smoke is normal, as is the odor of burning wood, the cat combustor consumes burnables such as creosote and turns them into heat, I suppose there is a lot of gases that are not burnable, and that is probobly a lot of what you see as smoke. It should smell pleasant, smoke that has a lot of creosote is pretty rank and has a distinct smell
More important is the amount of creosote being deposited in the chimney, I still get some, but a couple brush strokes removes the majority of it, twice a year max. My chimney cap usually catches the worst of it, and I might knock that off once a month (fortunately my stack is easily accessable). When it gets really cold (below zero) it is not unusual to see icecycles hanging from the cap with smoke coming out of it. It is not a bad idea to replace gaskets, if you have the "flapper" style door on the bypass, they can tend to collect crud that might fall down the chimney, if so, clean the groove that the door nests in and replace the gasket. Some blaze kings have a sliding door that is self cleaning and requires no gasket. There usually is a gasket that seals the combustor itself, at least the square combustors, the round or oval combustors don't have one, or at least mine didn't
If you charge the stove fully (what can easily be fit in the box, about 20-25 pounds of dry pine, maybe 30 or so of dry hardwood, when you can't get that much in, then its time to remove some ashes) it will take 2-3 hours for the wood to gas off and begin to charcoal. At that point, you will most likely see little but heat waves off the chimney. Remember you are used to burning lots of wood, and reloading often. Now you have to relearn a new stove technology, and once you do, you will regret not having one of these years ago.
These stoves are intended for long, even heat. I sometimes go a couple weeks on one match, some folks up north only need one match for a winter. IF that is the type of wood heat you want, the blazeking has no peers that I know of.
Little loads of wood and short fires are best left to the stoves with small fireboxes and no cat.
stockcarver said:
Actually, I believe the fragile nature of the cat is the very reason non-cats are the biggest part of the market, even if most of the problem is just perception.
Well put stockcarver!
I will agree with the above comment regarding the (mis)conception about cats. Although, I would like to add that the new SS cats seem to have improved the durability and have a lower light off point. All of the new BK Kings shipped today are shipping with a SS cat, I don't think the BKP is yet though. If I were looking for a replacement cat for any cat stove, I'd look into SS cat technology before buying a ceramic combustor.
I will agree with the above comment regarding the (mis)conception about cats. Although, I would like to add that the new SS cats seem to have improved the durability and have a lower light off point. All of the new BK Kings shipped today are shipping with a SS cat, I don't think the BKP is yet though. If I were looking for a replacement cat for any cat stove, I'd look into SS cat technology before buying a ceramic combustor.
Backwoods Savage said:
While I thought that my issues with the catalytic converter getting too hot (2000º+) were solved with a new door gasket, it turns out from subsequent burns that it is not. I have continued to do reading and I reread the Blaze King manual that was posted on their website and I found the following information:
"When selecting wood for a catalytic stove, do not use extremely dry wood or small pieces. Dry or small pieced of fuel will release too many volatiles early in the burn and flood the catalyst, keeping it from reaching the clean burn stage. In extreme cases, the catalyst may not reach clean burn stage for three hours."
I had mentioned that the wood had been stored inside over the winter. I am wondering if this may have caused the high cat temps and the increased smoke that I have seen early in the burn (first several hours) but not later in the burn.
This section of the manual has certainly got me thinking. I am fairly new at burning (1 year) but it is the first I have heard that wood could be too dry. Guess the cat does change things.
I have read somewhere (can't remember where) that wood can be too dry especially kiln dry, and can result in a very fast release in gas and smoke which could result in an overfire, but I would think this is rare. Maybe purchase one of those cheap moisture meters and split a piece and see what kind of moisture you have. How do you load your wood? Maybe you need to have a more tight load or load it side to side to slow the burn down more and get that front to back burn? Could also be the thermometer is off, they aren't always the most accurate things. I can see where you would be worried, those big BK cats aren't cheap!
Here is a blog with some great cat stove info.
http://www.firecatcombustors.blogspot.com/
Here is a blog with some great cat stove info.
http://www.firecatcombustors.blogspot.com/
Please do not think too poorly of me as you read.
I decided to replace the fire brick in my stove. I did not think that would help with overheating of the catalytic converter, but it was something I could do. Upon inspecting the badly deteriorating firebricks (20+ years old) I discovered some, shall we say, significant cracks and deformed surfaces in the metal of my wonderful stove. This stove had obviously been significantly over-fired in the past. There was a 1/16 inch crack in the rear of the stove and several cracks in the ceiling of the firebox as well, the largest being 1/4 inch
(that is wide not long) The crack in the back explains the leakage of air into the firebox from the outside causing it to get hot and stay hot. The cracks in the ceiling of the firebox explains the smoke that continued to come out of the chimney, as some/much of the smoke bypassed the cat. The crack in the back of the stove worried me (I know what you are thinking, he didn't send it immediately to the metal recyclers?) but it would be behind the firebrick when they were replaced. I purchased some fireplace and woodstove caulk and sealed all of the cracks, relined the stove and relit the stove last night. All I can say is WOW. (I know that is the same thing you are saying about me for very different reasons.) (I also used wood from outside that was not as dry as the remainder of the wood that was left over from last year. See earlier posts in this thread). The results were amazing. On a medium low burn, the stove is still putting out heat 18 hours later, albeit it has finally reached the end of its burn cycle. I will be getting my brother in law to come up and permanently weld the cracks at some point. Until then, heating with a woodstove has taken on a whole new meaning for me!! No smoke or creosote from a extremely slow burn that has allowed us to be comfortable and not opening up windows on mid 30 degree night and 60 degree day. And all that without maxing out the firebox. I can say that I am glad that I came upon catalytic stoves accidently. I would have avoided them otherwise.
Oh yeah. If you are buying a stove, open it up and check it out really good. The 1/4 cracks are fairly obvious when you are looking for them.
You can see why I still have "Firestarter" by my name.
I decided to replace the fire brick in my stove. I did not think that would help with overheating of the catalytic converter, but it was something I could do. Upon inspecting the badly deteriorating firebricks (20+ years old) I discovered some, shall we say, significant cracks and deformed surfaces in the metal of my wonderful stove. This stove had obviously been significantly over-fired in the past. There was a 1/16 inch crack in the rear of the stove and several cracks in the ceiling of the firebox as well, the largest being 1/4 inch
(that is wide not long) The crack in the back explains the leakage of air into the firebox from the outside causing it to get hot and stay hot. The cracks in the ceiling of the firebox explains the smoke that continued to come out of the chimney, as some/much of the smoke bypassed the cat. The crack in the back of the stove worried me (I know what you are thinking, he didn't send it immediately to the metal recyclers?) but it would be behind the firebrick when they were replaced. I purchased some fireplace and woodstove caulk and sealed all of the cracks, relined the stove and relit the stove last night. All I can say is WOW. (I know that is the same thing you are saying about me for very different reasons.) (I also used wood from outside that was not as dry as the remainder of the wood that was left over from last year. See earlier posts in this thread). The results were amazing. On a medium low burn, the stove is still putting out heat 18 hours later, albeit it has finally reached the end of its burn cycle. I will be getting my brother in law to come up and permanently weld the cracks at some point. Until then, heating with a woodstove has taken on a whole new meaning for me!! No smoke or creosote from a extremely slow burn that has allowed us to be comfortable and not opening up windows on mid 30 degree night and 60 degree day. And all that without maxing out the firebox. I can say that I am glad that I came upon catalytic stoves accidently. I would have avoided them otherwise. Oh yeah. If you are buying a stove, open it up and check it out really good. The 1/4 cracks are fairly obvious when you are looking for them.
You can see why I still have "Firestarter" by my name.
tdwolfe said:Please do not think too poorly of me as you read.
I decided to replace the fire brick in my stove. I did not think that would help with overheating of the catalytic converter, but it was something I could do. Upon inspecting the badly deteriorating firebricks (20+ years old) I discovered some, shall we say, significant cracks and deformed surfaces in the metal of my wonderful stove. This stove had obviously been significantly over-fired in the past. There was a 1/16 inch crack in the rear of the stove and several cracks in the ceiling of the firebox as well, the largest being 1/4 inch
Oh yeah. If you are buying a stove, open it up and check it out really good. The 1/4 cracks are fairly obvious when you are looking for them.
You can see why I still have "Firestarter" by my name.
Glad you have found the source of the problem. Hopefully welding will fix the problem and careful burning will not open them back up.
Glad you found the problem. What is wood stove caulk? Weld those cracks up a soon as you can, anything else will just be a band aid fix and won't last.
- Status
Similar threads
