Fed up with Combustors

I am going to say it again.. Thank you Highbeam and others for your knowledge and experience with BK stoves that are always presented in a helpful way!!

Your comradery makes this site better than others

 

If I recall correctly I remember reading somewhere BK's VP has also stated a steel cat can also be subjected to thermal shock, the cat itself doesn't crumble but the wash coat can still be harmed. On most stove designs as the air enters the stove with a cold air kit the air is warmed by the stove body before it enters the stove and hits the cat. Looking at the airflow in a Progress it seems the thermal shock from a leaky gasket would be less of a problem, the air even from a leak will likely be warmed before making it to the cat. The Princess cat is front and center, if the door or glass gasket is leaking the cold air has a direct shot to the front of the cat.

 

She.....

 

On the BK, the cold air is fed into the back of the stove and enters a rather huge chamber that spans the back of the stove behind the cat. Lots of residence time here to gain heat from the stove. Then from that chamber there are two pipes, about 2" diameter, to channel that intake air inside the actual firebox right next to the 1300 degree cat before spilling into the airwash. There is no other intake air supplied to the stove. No secondary air, cat air, or random holes. This very large intake preheat system and with the very low flow rates means the intake air gets lots and lots of preheating before entering the firebox. That is a large part of the secret sauce I think. Outside air at 5 degrees or inside air at 70 is not a consideration when the intake manifold delivers preheated air at I'm guessing 700-1000, but maybe higher.

Most of us do not see the thermal shock physical damage as was posted on this thread. In fact, the worst I've ever seen from a BK is cracks. The cats can plug though if your draft is very strong and you run high output a lot. That's not unique to BK, actually none of this is. Fortunately I have zero problems with plugging and just wear out cats.

 

I really like that IS. They didn't have it, or the PH, when I got my BK or I might have the IS right now. The fireview was the best match for my home at the time and due to the rear exit it has huge rear clearance requirements. When I finally melt my NC30 in the shop I think it will get replaced with an IS or a wood furnace.

 

Sorry guys, the price on the ceramic moved up to 210$. Inflation I guess. Interestingly the steel version is now just 250$. Gasket and shipping included on both.

 

I'll really need pics of the puddle.

 

That is how I have found all stove mfg's 'combustor life expectancy'- hopeful at best, just incorrect at worst. Sort of like 'salesmen's horsepower'..... perhaps a bit (read: ridiculously) overstated.

Replacing cats. is an ongoing cost that should be figured into the actual cost of burning wood if a person has a cat. stove. It is not as simple as cost though because the stove really will use less wood, far less IME, with a correctly operating cat. that it will with a defective cat. And even free wood is not really free as it must be cut, split, moved at least twice, pushed in the stove and taken out as ashes. I believe <most> people actually buy wood so it also has a real, actual cost that is directly reduced by using a cat. to burn the particulates that would otherwise go up the flue. I always recommend folks look at the price of a new combustor as well as the combustor warranty to determine what a given stove will actually cost to maintain a fairly fresh cat. in it before buying any stove. One of the big downsides of the two really large cat. stoves that I know of: the BK King and the Regency 5100 each have a $300 + cat. which is significantly more expensive than some others.

Brian

 

King's cat is just 260 shipped to your door.



Since the big cats are bigger it makes sense that they cost more. More precious metals. Going from 210$ for the princess cat to 260$ for the king cat is a jump of 24%. The king cat is 25% larger (80 CI vs 100). I do believe that this cost increase is justified and surprisingly consistent with cat size.

Didn't do the math with that goofy regency stove. If you're looking at the 5100 then perhaps you should also consider the kuma cat stove.

 

This thing about "warmed air" is not how stoves operate. The cat ( or tubes) doesn't care about the temp of the air ( I've spoken to one ).
From burning cats for a couple of decades, the cat light off depends on the firebox fire strength...period. Those with OAKs bringing in cold air have the same time for the cat to 'ignite'.
Just for kicks, your vehicle cat lights near immediately since engine temps are high on starting ( otherwise we'd never get out of our driveway ).
One of the main reasons I could not get the BK Ashford is that the thermometer is at the extreme rear that needs to be at least 6" from a non combustible surface; it would not fit in the 2 sided alcove or hearth.
Got this direct from BK in Washington. Nice customer service .
So far the non cat Jotul Rangely is bunn warming fine. ( Can we say "bunn" here ? )

 

Yep, looks like they either dropped the price a bit or it is for a different combustor- the only ones I found in that price range are 16 cell ceramic combustors. But a much higher count S.S. combustor for a BK King is $296 + $16 for shipping, and that is the cat. I would choose. About double the price of the same cat for an Ideal Steel. Given the same lifespan, the cost would double to maintain the cat. in a BKK as compared with and I.S. And that is with the new price of $175 for the I.S. cat- when I bought the stove, they quoted me $125 for a new cat (again, fine cell, S.S. type).

The biggest Kuma I saw is 3.6 cu. foot firebox, virtually the same as an I.S. but the Kuma does not have an ashpan and is not a hybrid. It also appears to require an 8" flue, which is a problem with my install. The Regency 5100 is a ~ 4.5 cu. ft. firebox and a significantly larger stove, almost a match for a BK K in firebox size.

Brian

 

Agreed!!

 

I tried to remember his name and drew a complete blank!!
Thank you for tagging him in this thread!

 

While it doesn't mtater one iota to me, I would have to assume the BK king combustor would have to be a heck of a lot bigger than the IS. The BK is strictly a cat stove and almost a full cubic foot bigger in capacity. It would only make sense....at least to me

 

I was not addressing whether it made sense or not, merely commenting on the actual cost. As I said, I think this should be a fundamental consideration when buying any woodstove that has a cat. as it will be a yearly, recurring cost (not buying a new cat. every year but how much it costs per year to maintain a working, responsive cat.).

The cost of a BK King combustor was a major point in my consideration of that stove as well as the very similar Regency 5100- cat. cost per year are virtually double the cost of maintaining the cat. in an I.S. for example (the stove I ended up buying).

Brian

 

Buck makes the 80 & 81 along with the 91 & 94 that are both cat/non-cat versions of the same stove/insert. I've never run them side by side but it IS possible to do with theirs.

 

bobdog2o02
Any updates on the air leak test or new SS cat?