2017-18 Blaze King Performance Thread (Everything BK)

[Ashful]

There's likely other factors for BK advising the cat probe reach the active zone before throwing the bypass. Maybe BKVP will elaborate on those other facts but until then I will go out on a limb and guess it has more to do with getting the rest of the stove up to temp to maintain a long clean burn without risk of stalling the cat initially. Maybe they figure it gives the surface moisture a chance to evaporate and bypass the cat.

This has been discussed before (annually, actually), so I might be safe speaking for BKVP on this one: The manuals aren’t written for the burning aficionados* that hang out at hearth.com. They’re written to be as simple to follow as humanly possible, so as to not scare off the stove newb’s.

There is no issue with closing the bypass before the needle hits “Active”, provided that you have some means of knowing the combustor has reached light-off temperature. For most of us, our experienced eye, watching load after load having come up and reached ignition, is that “means of knowing”. For those without this interest or experience, the needle is a safe way to get it done.

* insert your own term: nuts, fanatics, etc.

 

[Highbeam]

Are you advising that I follow the instructions in the manual and wait for the needle to enter the active zone? I'm afraid I would be replacing the bypass gasket three times a season if I did that.

Don't worry about the gasket, worry about the welded in (and flimsy) gasket retainers that can melt and sag if you get them too hot.

 

[WoodyIsGoody]

Don't worry about the gasket, worry about the welded in (and flimsy) gasket retainers that can melt and sag if you get them too hot.

OK, duly noted. And that sounds worse. But I don't want to mess with either if I can help it!

 

[Highbeam]

OK, duly noted. And that sounds worse. But I don't want to mess with either if I can help it!

Good deal.

Other reasons to engage as early as possible are to increase efficiency, decrease particulate emissions, decrease visible emissions, reduce chimney accumulations, get warmer faster, etc.

95% of cat failures are caused by thermal shock (leaky door gaskets according to BK) so if you can keep a tight door gasket then odds are very good that your cat will die from old age and not because of any other thing we can dream up. In other words, go for early engagement!

 

[lsucet]

I have better results like mentioned before making the fire at the front of the firebox as recommended by the manual. The cat get to activate zone quicker and and flue temperature stays under control.
I start minimum 3 fires a week on winters cause I don't burn 24/7 like many here. I had time to experiment different ways and the way the manual says I the best for me.

Now, about the retainer, I will think that they are more exposed to heat from the cat that from the firebox. After all nobody wants 1500 degrees at stove pipe cause it will melt but the cat can get up and more of those temperatures, why then the ritainers don't get damaged from the cat temperature?

 

[BKVP]

There's likely other factors for BK advising the cat probe reach the active zone before throwing the bypass. Maybe BKVP will elaborate on those other facts but until then I will go out on a limb and guess it has more to do with getting the rest of the stove up to temp to maintain a long clean burn without risk of stalling the cat initially. Maybe they figure it gives the surface moisture a chance to evaporate and bypass the cat.

The cordereite combustor get active usually in 20-25 minutes or less. The DuraFoil versions can cut that time in half.

 

[WoodyIsGoody]

The cordereite combustor get active usually in 20-25 minutes or less. The DuraFoil versions can cut that time in half.

That's about what I've been seeing, 10-13 minutes, even with over 50 hours "aging" on the combustor. Based on the fact that it lit off orange every time as soon as I closed the bypass, I'm sure it would have lit off even sooner had I tried. But I'm not pushing the light-off speed because I'm thinking it might shorten the time to the first vinegar cleaning. Well, based on the thermometer reading, I'm pushing it big-time!

BKVP, you probably missed my question on the previous page, I was wondering what kind of accelerated aging process is used to be able to EPA test an "aged" combustor after only 50 hours of aging.

 

[jetsam]

The cordereite combustor get active usually in 20-25 minutes or less. The DuraFoil versions can cut that time in half.

On that topic... do you think there's a reason I shouldn't "preheat" the cat by throwing a handful of kindling on top of the load so it burns right in front of the cat flame guard?

I understand that direct flame impingement is to be avoided, but the BK flame shield must be taking good care of it. My stock ceramic cat looked pretty good when I bathed it after the first 2 years, and 3 years is more hours than it's rated for anyway.

I don't see a practical downside for me and the cat lights off so fast that way. I guess it could have worse long term impacts for people who are expecting 10 years from their cat.

 

[WoodyIsGoody]

On that topic... do you think there's a reason I shouldn't "preheat" the cat by throwing a handful of kindling on top of the load so it burns right in front of the cat flame guard?

I understand that direct flame impingement is to be avoided, but the BK flame shield must be taking good care of it.

What I've noticed is that when I build a fire with the ignition in the middle of the load filling the firebox, the initial flames hit the top center of the firebox (right behind the forward most steel channel) and proceed out the bypass. But, as the fire builds in intensity, it's not long before some flames are licking around the steel channel and flowing across the face of the flame guard (without getting sucked inside). This seems like a good way to heat the combustor without impingement.

It doesn't make sense why the flames travel forward (when the draft is behind). But the same thing happens in reverse after the bypass is closed. The flames travel back towards the closed bypass. This seems counter-intuitive but it happens so there must be a reason.

 

[SculptureOfSound]

BKVP or someone who owns a Sirocco 25 or Ashford 25 insert... can you please tell me the exact vertical height of the door flange.

In the mantel clearance it says 38" (24" w/ mantel shield) required from the door flange height to mantel, but none of the drawings show the door flange height. I mistakenly thought it was the 24 1/4" height to the top of the unit, originally, but the door flange appears to be 3-5" lowers than that. Those 3-5" will make a big difference in my situation.

 

[Marshy]

What I've noticed is that when I build a fire with the ignition in the middle of the load filling the firebox, the initial flames hit the top center of the firebox (right behind the forward most steel channel) and proceed out the bypass. But, as the fire builds in intensity, it's not long before some flames are licking around the steel channel and flowing across the face of the flame guard (without getting sucked inside). This seems like a good way to heat the combustor without impingement.

It doesn't make sense why the flames travel forward (when the draft is behind). But the same thing happens in reverse after the bypass is closed. The flames travel back towards the closed bypass. This seems counter-intuitive but it happens so there must be a reason.

Natural circulation of the combustion air in the firebox. In the King, all the air comes into the firebox through the air wash on the door and causes the smoke in the firebox to roll forward and mix with incoming fresh air kind of like a re-burn of sorts.

 

[Ashful]

I have better results like mentioned before making the fire at the front of the firebox as recommended by the manual. The cat get to activate zone quicker and and flue temperature stays under control.
I start minimum 3 fires a week on winters cause I don't burn 24/7 like many here. I had time to experiment different ways and the way the manual says I the best for me.

Even those of us who burn 24/7 can do well by just plowing the ash down and back, and raking the hot coals to the front of the floor, which serves to light the front of the new load first. I believe this does a good job of getting the combustor up to temperature first, while simultaneously keeping that whole bypass assembly cooler, or at least that's what I tell myself.

Now, about the retainer, I will think that they are more exposed to heat from the cat that from the firebox. After all nobody wants 1500 degrees at stove pipe cause it will melt but the cat can get up and more of those temperatures, why then the ritainers don't get damaged from the cat temperature?

They're out of the direct path. You're thinking in terms of a static situation, but those retainers are heat-sunk to a door that's heat-sunk to other cooler parts of the stove. Once the bypass is closed, they're not seeing direct flame impingement.

 

[lsucet]

Even those of us who burn 24/7 can do well by just plowing the ash down and back, and raking the hot coals to the front of the floor, which serves to light the front of the new load first. I believe this does a good job of getting the combustor up to temperature first, while simultaneously keeping that whole bypass assembly cooler, or at least that's what I tell myself.


They're out of the direct path. You're thinking in terms of a static situation, but those retainers are heat-sunk to a door that's heat-sunk to other cooler parts of the stove. Once the bypass is closed, they're not seeing direct flame impingement.

Understood. Is good to know.

 

[jetsam]

First shoulder season fire is on the radar!

Probably just one low 24 hour burn, back into october summertime after that.

 

[Scoutin Wyo]

Folks. I want to get a new ceramic cat for the season as a back up. My cat works but drops off sooner than it did two years ago. Where can I order a good BK approved cat? My local dealer is not very trust worthy when they tried to sell me junk door gasket and claimed BK stoves use the same cheap gasket all stoves do.
Thanks for the help!


Sent from my iPhone using Tapatalk

 

[Ashful]

Firecatcombustors.com

 

[kf6hap]

Due to the much quicker light off, I much prefer the steel cat. The ability to get the stove operating catalytically in less than 15 minutes is worth the extra cost. My 2 cents.

First burn for the year last night.

 

[Ashful]

Due to the much quicker light off, I much prefer the steel cat. The ability to get the stove operating catalytically in less than 15 minutes is worth the extra cost. My 2 cents.

First burn for the year last night.

SteelCat has a few advantages, one being faster light-off. In my opinion, their biggest advantage is that they don’t crack from thermal shock, or crater from flame impingement. Thermal shock and flame impingement are two of the biggest killers of ceramic cats.

However, if we’re going to be fair, we have to acknowledge their trade-offs. I have had some issues with clogging on both of my SteelCats, one of the two happening frequently enough to be a real problem. I have seen at least one or two other members of the forum with the same issue. Also, some of the SteelCats (not BK) are made with Diesel Foil, and these warp badly enough to close off the passages, under high cat temperatures.

 

[WoodyIsGoody]

Due to the much quicker light off, I much prefer the steel cat. The ability to get the stove operating catalytically in less than 15 minutes is worth the extra cost. My 2 cents.

First burn for the year last night.

I have about 150 hours on my Chinook this fall. Today I awoke at 7:30am to 37 degree outside temperatures and the house was the same temperature as when I went to bed (72F) with the cat thermometer still in the active zone. I fired up the cold stove last night at 10:15pm with a half load of smaller mixed wood, burned on med. for 1 hour and then turned it to low and went to bed.

General observations on starting a new fire for new fire bugs.

Sometimes less is more.

When starting a new fire in a cold stove, restricting the fresh air a bit can help build higher temperatures more quickly. This is true both before and after the door is latched. One thing I like about my new BK is that the door latch makes it easy to fine-tune how much air a new fire gets. It's good for the air of a new fire to be restricted a bit. Reducing the intake air reduces dilution of hot flue gasses with cooler fresh air. This makes the gasses in the chimney hotter and lighter which increases draft, fanning the flames and causing the fire to build more quickly. The same principle can apply after latching the door shut. Over-restricting the air will obviously choke the expansion of the fire so the key is to just slightly restrict the air so unlimited quantities of fresh air can't get sucked up the chimney along with the hotter smoke.

Fire temperature matters more than fire size.

The combustor doesn't know how big your fire is, it only knows what the temperature of the exhaust gasses are. For this reason I generally build a wooden "firebox" within the firebox. Everyone knows that wood is a good insulator and that small fireboxes heat more quickly than large fireboxes. So put your smaller wood pieces, the ones that you want to ignite first, in the middle-front, with the big splits on the firebox floor, north-south (and sides and or top depending upon your longer term goals). If you have a half-length big split handy, you can put it in the middle-back, before loading your smaller wood in front of it. Then finish loading the firebox around the starting area leaving a small area in the middle-top open as a "chimney" for your smaller wood pieces. By creating this firebox within the firebox you will achieve very hot temperatures, hot enough to re-burn the smoke inside the mini-firebox, which is what raises temperatures high enough to light off the combustor. It's important that top exits are restricted but that there is a small place to act as a chimney to your firebox within. This is also very gentle on the stove since it is shielded from the intense heat.

By combining the above two concepts, you can create high temperatures very quickly and without consuming a high percentage of your load in the process. This works well in both catalytic and tube stoves but has more benefit in a catalytic equipped stove. You can think of it as building a little rocket stove within your firebox.

 

[kf6hap]

Start of year 3. One quart of soot from a 17' 6" pipe. Wood is the primary heat source. 20 hours burn time on pine. The cat operates like it is new. Gone are the days of "will it be cold in the morning?". Last night my wife did it again: Oh no, the fire went out!

 

[Scoutin Wyo]

SteelCat has a few advantages, one being faster light-off. In my opinion, their biggest advantage is that they don’t crack from thermal shock, or crater from flame impingement. Thermal shock and flame impingement are two of the biggest killers of ceramic cats.

However, if we’re going to be fair, we have to acknowledge their trade-offs. I have had some issues with clogging on both of my SteelCats, one of the two happening frequently enough to be a real problem. I have seen at least one or two other members of the forum with the same issue. Also, some of the SteelCats (not BK) are made with Diesel Foil, and these warp badly enough to close off the passages, under high cat temperatures.

Have you purchased new steel cats from firecatcomustors.com? I want to make sure I don't end up with a diesel foil cat! Thanks again!

 

[BKVP]

Have you purchased new steel cats from firecatcomustors.com? I want to make sure I don't end up with a diesel foil cat! Thanks again!

Firecat does not buy substrate from the diesel foil supplier. You'll get Durafoil from them.

 

[WoodyIsGoody]

Webby you are indeed correct. Regulators and test agencies are well aware of the hyperactivity of new combustors. EPA's method 28R test protocol requires 50 hours of aging prior to emissions testing.

BKVP, if this isn't too sensitive of a question to answer, do you mind a quick explanation of how the combustors are aged in only 50 hours? I have about 150 hours on mine and I haven't noticed any big fall off in performance.

I know you're probably just busy so forgive me for asking a third time but I assume you just missed my question.

 

[kf6hap]

An excellent read on combustors:
http://www.chimneysweepnews.com/Combustors.htm

 

[lsucet]

I think is because new cats are overactive, testing one with approximately 50 hrs of burn time, possibly give them better results and more accurate data of what can be expected emission wise for the life of the cat? I think everything has a break-in period. Maybe is not the right terminology but you get the idea.