Blaze King 40 catalyst issues

[Slate Dale]

Blaze King 40 catalyst does not light after only 2 winters and 5 or 6 cords. Still glowing two weeks ago, last week faint glow at the ends. Should it be vacuumed or cleaned somehow? What can be done other than removal and replacement? How do I know if it is worn out? If I remove it is there anything I can look for and see that would tell me why it didn't last long? This is a "disaster" because the very expensive part lasted much less than the expected 12,000 hours. I am looking for my papers now to see if there is a warranty on it.

I've been using good dry split cordwood. and also some wood sawdust and chip "bricks" I get from a local hardwood flooring manufacturer. The fuel is all dry and I have no problems with creosote liquid anymore, and amazingly, the window glass always stays clear. Before I open the door for re-fueling, I disengage the cat vent to avoid cool air moving over it that might cause thermal shock damage. If the fire has burned down to coals by morning, after I re-load it I don't re-engage the cat vent until the temperature reaches the active zone, and I've been burning the stove with the thermostat at 80 to 100% steadily for the last month, 24-7. All the while I see the cat getting dimmer and dimmer, and now it doesn't glow at all, not even at the ends. I know that a cat doesn't glow when a fire has burned down to coals, but I expect that a fresh load of cordwood, even if it's tested dry, will produce enough smoke to make a cat glow.

If this cat really is worn out and I don't buy another cat, how much less efficient is the stove without a good cat?

If the cat is worn out and isn't doing anything, is it better to vent out the back of the stove, or to vent over the worn-out cat?

Suppose I remove a worn-out cat and don't replace it, letting the space open, how does that affect the performance of the stove?

Yes I will probably replace the cat, but first I need to learn why it didn't last even a third as long as I expected. Thanks for your help and advice.

 

[Slate Dale]

Should it be vacuumed or cleaned somehow? What can be done other than removal and replacement? How do I know if it is worn out? If I remove it is there anything I can look for and see that would tell me why it didn't last long? This is a "disaster" because the very expensive part lasted much less than the expected 12,000 hours. I am looking for my papers now to see if there is a warranty on it.

I've been using good dry split cordwood. and also some wood sawdust and chip "bricks" I get from a local hardwood flooring manufacturer. The fuel is all dry and I have no problems with creosote liquid anymore, and amazingly, the window glass always stays clear. Before I open the door for re-fueling, I disengage the cat vent to avoid cool air moving over it that might cause thermal shock damage. If the fire has burned down to coals by morning, after I re-load it I don't re-engage the cat vent until the temperature reaches the active zone, and I've been burning the stove with the thermostat at 80 to 100% steadily for the last month, 24-7. All the while I see the cat getting dimmer and dimmer, and now it doesn't glow at all, not even at the ends. I know that a cat doesn't glow when a fire has burned down to coals, but I expect that a fresh load of cordwood, even if it's tested dry, will produce enough smoke to make a cat glow.

If this cat really is worn out and I don't buy another cat, how much less efficient is the stove without a good cat?

If the cat is worn out and isn't doing anything, is it better to vent out the back of the stove, or to vent over the worn-out cat?

Suppose I remove a worn-out cat and don't replace it, letting the space open, how does that affect the performance of the stove?

Yes I will probably replace the cat, but first I need to learn why it didn't last even a third as long as I expected. Thanks for your help and advice.

Updates on old issues: The first season I had some trouble with creosote liquid in the stove and pipe that was due to cordwood not really dry enough, and trying to achieve the advertised "very long burn time." I use very dry wood and a few "bricks" now and re-load every six hours on top of red hot coals, so even the glass stays clean. The Princess insert upstairs is hardly ever used, because the King 40 in the basement heats the whole house. The King works fine on the concrete floor and very near the poured cement foundation wall. The thermostat seems to work well in this position, too, responding the way it should, so apparently there is enough air movement between the stove and the hot comcrete wall for the thermostat not to be thrown off. The negative draft continues to happen if I try to start to stove in mild weather and the chimney is cool. I need to open the basement doors and get it off to a hot start with some paper and very small kindling for a few minutes, before closing the doors, and then I find the draft goes up constantly. There has been no problem with negative draft in very cold weather. The Princess insert, located upstairs, also has negative draft with a cold start in mild weather, which means cool air is probably coming down the chimney into the house through it when the stove isn't being used. I have thought about stuffing something in the vents of one or both of these stoves to stop negative draft from happening when not being used, especially for the insert because it is hardly ever used, and might cause a net energy loss to our home. I made a steel block-off plate for the pipe (flexible) and sealed around it well with stove cement and rockwool when I installed the insert, so the only way outdoor air can come down the chimney into the house is through the pipe and the stove.

 

[begreen]

The cat does not need to glow in order to function. Is it still staying in the active range? Is there smoke coming out of the chimney? If no smoke and an active cat, it's ok. If the opposite, then the first cat is under warranty.

 

[Slate Dale]

The cat does not need to glow in order to function. Is it still staying in the active range? Is there smoke coming out of the chimney? If no smoke and an active cat, it's ok. If the opposite, then the first cat is under warranty.

That's interesting. The temperature gauge on top of the stove is almost always in the "active" range, except some mornings when the fire has burned down to coals. I burn continuously now.

My understanding, or misunderstanding, is that a catalyst is only doing what it needs to do when it is glowing orange or red. If I load up with cordwood and never see it glow anymore, every time I check, I think it's not working anymore. The wood is always the same wood yet the cat has glowed less and less this second season, and now it is dark ALL the time, even after I fill the stove to the top with a very large fresh load. The "needle" on the temperature gauge on the top of the stove often goes to the end of the active zone or sometimes PAST it, but still the cat doesn't glow.

Going back to my original post on this thread I asked some questions, and the first question was whether the cat might be dirty and if it is dirty is possible to CLEAN the cat, like by vacuuming it or something? Maybe it is coated with ash. But I try to minimize that: When I am ready to re-load, I change the venting direction so that no cold air flows over the cat to cause thermal shock damage, and so that any ash I stir up while re-loading goes up the back of the stove instead of over the cat.

 

[begreen]

The cat definitely will not be glowing red all the time. If there is no smoke and the thermometer shows it's in the active zone, then the cat is still working.

It definitely is possible and recommended to clean the cat. There are several postings on that topic. I'll let BK owners tell you their preferred methods. To start with, follow the procedure recommended in the manual.

Under certain conditions, ash particles may become attached to the face of the combustor. These may be seen while the combustor is in the glowing stage, or when the fire is out. Any deposit on the visible face of the combustor should be removed. Wait until the fire is out and the appliance is cold before performing any cleaning. Brushing the combustor with a soft bristle paint brush will remove some deposits. Passing a vacuum cleaner wand or brush near the face of the combustor will remove most deposits. (Hot ash in a vacuum cleaner bag will burn, may melt the vacuum or cause a house fire. Exercise caution and never clean the appliance when the appliance or ashes are hot.) Never scrape the combustor with any hard tool or brush. Never run pipe cleaner through the individual cells of the combustor. This is not needed, and may do more harm than good. 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.

 

[stoveliker]

My cat surely doesn't always glow. Trust the cat gauge. If active you should be good. Proof is in the pudding (smoke out of the chimney or not).

Do read the manual again. I believe it mentions that the cat doesn't need to glow for it to do its work. In fact cats start working around 500-600 F, which is below visible light emission.

From what I read you don't need to clean the cat.

You can vacuum it next time it's cold, for fly ash.

Don't take the cat out without having new gasket to put it back.

Running the stove without cat is dirty business.

 

[Slate Dale]

My cat surely doesn't always glow. Trust the cat gauge. If active you should be good. Proof is in the pudding (smoke out of the chimney or not).

Do read the manual again. I believe it mentions that the cat doesn't need to glow for it to do its work. In fact cats start working around 500-600 F, which is below visible light emission.

From what I read you don't need to clean the cat.

You can vacuum it next time it's cold, for fly ash.

Don't take the cat out without having new gasket to put it back.

Running the stove without cat is dirty business.

Did your cat glow a lot more when it was new, and less and less over time with same fuel and other conditions?

I had thought the temperature gauge on top of the stove was really just telling the temperature, and if a fire is really hot the needle on the gauge will be in the "active zone" whether or not a cat is working and even if the cat has been removed.

I plan to vacuum it when the stove is out and cold. It doesn't look dusty, though. Time will tell.

 

[stoveliker]

Did your cat glow a lot more when it was new, and less and less over time with same fuel and other conditions?

Yes, that's normal.

I had thought the temperature gauge on top of the stove was really just telling the temperature, and if a fire is really hot the needle on the gauge will be in the "active zone" whether or not a cat is working and even if the cat has been removed.

No, in fact when I dial down the air, the cat gauge goes up because the cat will see more smoke to combust (producing more heat).

I plan to vacuum it when the stove is out and cold. It doesn't look dusty, though. Time will tell.

 

[Slate Dale]

Is this stove the same design as before the combustor was added to meet EPA requirements?

 

[stoveliker]

No, it was designed for operation with the cat. It's not a normal stove with a cat added to it. New, coherent system designed to work only this way.

 

[Slate Dale]

Yes, that's normal.

No, in fact when I dial down the air, the cat gauge goes up because the cat will see more smoke to combust (producing more heat).

When you say you dial down the air, do you mean turn down the thermostat on the rear of the unit? Or do you have some kind of damper, out an outside air supply you can reduce?

I have the thermostat turned all the way up most of the time now, and now I'm thinking: Am I missing out on extra smoke-derived heat if I'm letting smoke go up the pipe too easily by turning up the thermostat letting too much air in?

 

[Slate Dale]

Another worry is about too much draft. I've heard of "too much draft, such as a too-high chimney" that "sucks most of the heat outside."

Maybe there is a fine balance and little margin of error between having too much and too little draft with these modern stoves?

When I installed this stove I made sure that there was at least the amount of vertical rise required in the manual, then two 45 degree turns and about 20 feet of vertical rise through 8 inch vermiculite-insulated rigid stainless pipe through the brick house chimney.

I don't have an electric fan in this stove because I was trying to keep it simple. I wonder how much heat I am losing up the chimney because the stove doesn't have a fan? Also, does an outside air supply improve heating efficiency?

 

[stoveliker]

When you say you dial down the air, do you mean turn down the thermostat on the rear of the unit? Or do you have some kind of damper, out an outside air supply you can reduce?

The thermostat

I have the thermostat turned all the way up most of the time now, and now I'm thinking: Am I missing out on extra smoke-derived heat if I'm letting smoke go up the pipe too easily by turning up the thermostat letting too much air in?

In the end, the point is to set the thermostat at the position that the stove gives off the amount of heat that you need to get the home at the temperature you want.
Or, another approach is to set it at a position where the burn time meets your reloading schedule and provides a base load of heat, and you let another system modulate on top of that to get the home temps where you want.

Efficiency does possibly decrease a tiny bit when burning at a higher rate, but according to BK, not significantly so.

 

[stoveliker]

Another worry is about too much draft. I've heard of "too much draft, such as a too-high chimney" that "sucks most of the heat outside."

Maybe there is a fine balance and little margin of error between having too much and too little draft with these modern stoves?

When I installed this stove I made sure that there was at least the amount of vertical rise required in the manual, then two 45 degree turns and about 20 feet of vertical rise through 8 inch vermiculite-insulated rigid stainless pipe through the brick house chimney.

I don't have an electric fan in this stove because I was trying to keep it simple. I wonder how much heat I am losing up the chimney because the stove doesn't have a fan? Also, does an outside air supply improve heating efficiency?

The best way that assess draft is to measure it with e.g. a magnaehelic. But a 20+2 ft chimney with two 90 degree beds (one from 2 45s) is not too bad.

A fan helps extract more btu per hr which makes the burn rate go up (unless the thermostat is already at max). I don't think it increases efficiency. It also helps move the heat to farther away from the stove.

Outside air supply does not change the stove efficiency much, but does improve home heating efficiency because you're not pumping air up the chimney that you already spent btus on to heat it, and that needs to be replaced by cold air leaking in from cracks.
I believe you have a basement stove (as have I). Be aware that an outside air connection should not ever go up. It should exit at or below the height it is connected to the stove. Otherwise there is a risk it might act as a chimney reversing air flow, creating fire hazards by having hot flue gases in that air connection.

 

[kennyp2339]

Start with a top down approach, make sure the chimney from stove collar to cap is clean, especially the cap.
Make sure the inside cat chamber where the by-pass swings open and close is free from debris / fly ash, a good vacuuming w/ a flash light works.
I have a small shop vac with a 1 1/2” or 2” hose so occasionally I will take the front flame shield off the cat and run the vacuum end over the face being careful not to make direct contact with the cat itself, this removes any fly ash accumulated in the cells and allows more surface area for the smoke to pass through and hopefully get reburnt.
Testing the cat - full load of wood, let the load catch, keep the stove on high, close the by-pass and let her rip for 20-30 min, the cat probe should be 1-2 o’clock, cut the t-stat to below the half way setting and see how the cat probe holds, if the needle settles at the noonish area and remains there for hours then your still good, if the needle wains lower and falls close to the active / inactive range then it’s time to replace the cat.

 

[Slate Dale]

Start with a top down approach, make sure the chimney from stove collar to cap is clean, especially the cap.
Make sure the inside cat chamber where the by-pass swings open and close is free from debris / fly ash, a good vacuuming w/ a flash light works.
I have a small shop vac with a 1 1/2” or 2” hose so occasionally I will take the front flame shield off the cat and run the vacuum end over the face being careful not to make direct contact with the cat itself, this removes any fly ash accumulated in the cells and allows more surface area for the smoke to pass through and hopefully get reburnt.
Testing the cat - full load of wood, let the load catch, keep the stove on high, close the by-pass and let her rip for 20-30 min, the cat probe should be 1-2 o’clock, cut the t-stat to below the half way setting and see how the cat probe holds, if the needle settles at the noonish area and remains there for hours then your still good, if the needle wains lower and falls close to the active / inactive range then it’s time to replace the cat.

Thanks. That test makes sense. I'll try it shortly. If the cat is eating smoke and carbon dioxide, the temperature will hold when the flames are choked down. If the temperature measured by the cat thermometer on top of the stove goes up or down with the flames or no flames, that would indicate the cat that doesn't glow anymore really isn't working. I'll let you know what I find.

I can't vacuum the cat until I take a mid-winter break from burning, for a day or two, when this cold weather pattern ends next week. I will remove ashes then also. Thanks for your advice and experience.

 

[Slate Dale]

The best way that assess draft is to measure it with e.g. a magnaehelic. But a 20+2 ft chimney with two 90 degree beds (one from 2 45s) is not too bad.

A fan helps extract more btu per hr which makes the burn rate go up (unless the thermostat is already at max). I don't think it increases efficiency. It also helps move the heat to farther away from the stove.
. It should exit at or below the height it is connected to the stove. Otherwise there is a risk it might act as a chimney reversing air flow, creating fire hazards by having hot flue gases in that air connection.

But a 20+2 ft chimney with two 90 degree beds (one from 2 45s) is not too bad.

it's almost 3 feet from the stove top to the first 45, and less than two feet to the second 45 and then straight up the 20 foot rigid stainless 8 inch pipe inside the brick chimney packed with vermiculite insulation. If I extend the chimney pipe even higher, above the chimney top, will that help or harm efficiency? I have read or heard it said that "too much draft will suck the heat out of a stove." When I installed the stove I think I met all the requirements in the manual.

A fan helps extract more btu per hr which makes the burn rate go up (unless the thermostat is already at max). I don't think it increases efficiency

Yes that's what I was thinking. Running air through it with a fan is like the water running around the sides of a wood boiler: In both cases, the stove firebox and the boiler firebox, are being cooled off a lot by the forced air or pumped water and will need to burn more fuel and at a higher rate to compensate for the cooling in order to prevent creosoting. If the Blaze King 40 didn't have the "second skin" of sheet metal over the outside the firebox it would be a radiant heat source only. With the second skin or air jacket It tries to be both a radiant stove and an electric fan-forced convection stove. The outer skin on the sides and back stops a lot of radiant heat but the window certainly emits it well.

 

[stoveliker]

I would not extend anything now. The first 3 ft is good. Then 20 ft is good too - your chimney should (normally) provide sufficient draft.

A stove is never "radiant only"; much convection happens along any (vertical) wall that's heated.

I would not get hung up on radiant vs convective. What matters is how much BTUs you make (pounds of wood per hour) versus how much goes up the chimney (flue gas temperatures). If one has low flue temps, that means the BTUs get more pushed into the room - regardless of the fraction being convective or radiant.

The point of all this is that I have not seen any indication that something is awry. The cat does not need to glow to work. If you dial down the stove (in a few steps) from burning to no flames at all, and after a stabilization time of say 15 minutes there's no smoke - then all is working as it should, as we all know that smoldering wood smokes.

I think you're good. It's a simple fact that cats are initially "hyperactive", i.e. glowing like the devil is chasing them. After they age a bit, they mature and settle down their behavior. I think that's what you see, as I don't see anything being off the mark here.

If you're concerned, do what Kenny suggested - it's the proper version of my three lines above.

 

[begreen]

Slate Dale, Stoveliker has given good advice. It sounds like information overload has one is reading too much into something that may be working fine.

 

[Slate Dale]

I just finished the test you suggested. I filled the firebox with more cordwood on top of a lot of already-burning cordwood, over a bed of red coals. The stove was hot and flames shot up to the cat. I let it roar for awhile and the "needle" was around two o'clock. Then I turned the thermostat back half-way, and the flames almost disappeared, and then I left, and came back about a half hour later. When I came back, the needle was still in the same place. There were only flickers instead of flames even though the firebox was filled, and I noticed a very faint glow in a small part of (not all over) the cat, not bright orange all over like I was used to seeing but enough to prove it is still working a little bit!

 

[stoveliker]

Okay. Glad to hear.
The glow does show it's doing something as if it was dead it would not glow when there is no flame.

The point made above is that not seeing any glow does not mean it's not working. While I am a bit surprised the cat gauge did not go up after dialing down, all that is less relevant than an observation of what comes out of your chimney. So did you take a peak at the chimney (or was it too dark already)?

 

[Slate Dale]

While I am a bit surprised the cat gauge did not go up after dialing down, all that is less relevant than an observation of what comes out of your chimney. So did you take a peak at the chimney (or was it too dark already)?

Yes I saw smoke. But there is almost always some visible smoke coming out of the chimney, and cold starts are very smokey.

The cat gauge did not go up after lowering the thermostat halfway and turning flames into flickers, but it did stay in place and there was a faint glow, not over all but only in a small part of the cat surface indicating it really is still working but not very well. I was burning on "high" and hadn't seen any glow at all in recent days.

I don't want to run the stove on "low" to continue the experiment now, because we need maximum heat from this stove until this cold wave passes. I just remembered the cat glowing bright and now it doesn't.

 

[stoveliker]

Hm. If the smoke was smoke, and it was a good while after turning it down, I wouldn't like that.
If the smoke was steam, all is well.
Does it dissolve in a few feet or does it dilute but remain?

The higher i burn the less glowing i see because the flames are eating the fuel, leaving less for the cat. (Until flames start reaching the cat).

In fact I can see a cat brightening when flames go out and dimming when they come back (as sometimes happens in few minutes cycles at some settings).

Bottom line: don't be hung up on glowing. I run for many hours without any glow. (But no smoke.)

 

[BKVP]

The thermostat

In the end, the point is to set the thermostat at the position that the stove gives off the amount of heat that you need to get the home at the temperature you want.
Or, another approach is to set it at a position where the burn time meets your reloading schedule and provides a base load of heat, and you let another system modulate on top of that to get the home temps where you want.

Efficiency does possibly decrease a tiny bit when burning at a higher rate, but according to BK, not significantly so.

According the the actual tests done at the time of emissions testing, not just BK!

 

[BKVP]

Hm. If the smoke was smoke, and it was a good while after turning it down, I wouldn't like that.
If the smoke was steam, all is well.
Does it dissolve in a few feet or does it dilute but remain?

The higher i burn the less glowing i see because the flames are eating the fuel, leaving less for the cat. (Until flames start reaching the cat).

In fact I can see a cat brightening when flames go out and dimming when they come back (as sometimes happens in few minutes cycles at some settings).

Bottom line: don't be hung up on glowing. I run for many hours without any glow. (But no smoke.)

I was just in Fairbanks. "Smoke" was everywhere. White smoke that is....steam from the first stages of combustion in ultra cold environment. I was informed at -20F and lower you can almost not even tell the difference...except steam is lighter in color.

BKVP