2017-18 Blaze King Performance Thread PART 2 (Everything BK)

[SuperJ]

I have a question about the thermostat operation.

When turned down does the thermostat close when the temperature is high enough and then only open as far as it is set to or will it open above the set point?


Lopi Rockport
Blaze King Ashford 25

You can think of the knob as setting the max position, as you add heat the stat will close. When your insert is cold try listening while you turn it. I think you can hear it click softly when it fully opens (similar to the closed click). For me it occurs fairly close to wide open.

 

[kf6hap]

I get the smoke smell 100% of the time. High low. 50 degrees 0 degrees. It bothered me alot when I first got the stove. Now im just used to it. It's the bbq smell over the top of the door on the hinge side. I do only have about 15.5 feet of chimney with 2 offset 45s. But I get great burn times, 24 hours easily. I also have the ash pan issue on my Ashford 30.1. But the house is warm and the wife don't complain about it anymore.

Just a few more feet of flue, if possible, will most likely help greatly- to the point of being a non-issue.

To be very honest, every stove I have had emitted some odor/smoke, especially at the frequent reload. Some would belch out smoke unavoidably. Back in '75 I installed an exhaust fan to deal with it. Some odor is always expected. Hot iron and steel have an odor. My older stoves made a lot more creosote and I could smell it on hot days. Once again, my "problem" is gone.

 

[Nigel459]

I get the smoke smell. But it's backwards for me. No smell on low, but on high there is a definite creosote smell when when I walk into the room (30ft from the stove, to be clear I'm not sniffing around at the gasket looking for problems). So far it hasn't been cold enough to warrant running on high other than when I reload for a bit. The smell doesn't come on too strong for the first 30 minutes or so, I think it's coming from the hinge side of the gasket based on how creosote soaked that section of the gasket looks.
I did speak with Blaze King Canada, and he suggested a door alignment since the whole door seems shifted towards the latch side (based on the impressions in the gasket material). On the Ashford the door is attached to the front casting and there are bolts that can be adjusted for left/right alignment. I haven't done it yet, it's hard to find a day warm enough to let the stove cool off for some tweaking.
If the door adjustment doesn't fix it, I'll try a new gasket.

Hmm I'm sure you're right but is there no chance it's paint curing? I don't know how old yours is but we still get a very faint whiff of it when our month-old stove goes from cold to hot... seems strange that it's "backwards" for you...

 

[Nigel459]

All this talk of smoke smell...
None whatsoever for us. I was worried what I thought was a long chimney run @ ~23' might produce overdraft but it doesn't... and I sure am glad to have it now.

 

[Tegbert]

You can think of the knob as setting the max position, as you add heat the stat will close. When your insert is cold try listening while you turn it. I think you can hear it click softly when it fully opens (similar to the closed click). For me it occurs fairly close to wide open.

That is what I figured watching mine move. It just seems weird to me that it closes completely at about the 2 o’clock position. Why still have thermostat travel that much past close if it doesn’t open was what brought up the question. Just random thoughts waiting for parts to come in is all.


Lopi Rockport
Blaze King Ashford 25

 

[kf6hap]

These thermostats are not calibrated with accuracy traceable to NIST. They have no temperature indications at all but they could! It is for each of us to discover the useful region of travel. Mine is 3:30 to a high of 5:30 and 6:00 at startup. This is how they work:

You set the pointer to where you decide. This represents a temperature X. Above X the combustion air is decreased. Below X the combustion air is increased.

Error
The "error", or how far away from setpoint the actual temperature is called error. An empty stove will have a great amount of error because it can not raise the temperature. The other way around, A stove full of softwood will operate somewhere above the setpoint temperature.

The further away from setpoint the stove is the more the thermostat will react to change the airflow-proportionally. This temperature control system is called "Proportional Control". All proportional control systems have some error.

These systems are very very difficult to design and adjust to be effective under an extremely wide range of operational conditions. The BKs are the only stoves to possess this exceptional thermostatic control. The proof is in the unequalled burn times.

TMI?

 

[SuperJ]

That is what I figured watching mine move. It just seems weird to me that it closes completely at about the 2 o’clock position. Why still have thermostat travel that much past close if it doesn’t open was what brought up the question. Just random thoughts waiting for parts to come in is all.


Lopi Rockport
Blaze King Ashford 25

I suspect it has something to do with reusing the thermostat assembly on different models that require different calibrations. BK probably has a process in the factory where they heat up the thermostat assembly to a specific high temperature, and tune it's position to a specific %open that is different for each model.
If I had to guess it's tuned to a high temp position, where the stat is set to the highest position, and must close off to a certain minimum above a certain temperature (prevent overfire). The low position (cold closed) would end up where ever it is, based on the result of the high temp calibration.
The important thing is that you can set the intake to fully closed (minus the min FA hole). It seems like some people are tempted to modify non-BK stoves to further restrict intake air. On BK stoves this isn't necessary since the factory low is so low already, (even if it occurs higher than the min stat position). This is a confusing thing the manual doesn't handle well. The manual shows setting the stove to min on the stat, that would result in the air intake never opening at all even with a dying fire, and would leave a lot of un-burnt fuel.

@BKVP A BK factory tour/video would be interesting, the whole thermostat thing can't be much of a secret after all these years. But you wonder why no-one else seems to make a similar product. There must be something to the firebox design to that allows for precise control from the thermostat, maybe most other fireboxes hold too much heat causing fuel to be consumed quickly. Seems like a tricky balancing act to keep the firebox cool enough to go 24+hrs, but insulated enough that it doesn't extinguish at low burn rates.

 

[oldbluedeer]

So, from what I gather, 3 things can cause smoke smell with tested seasoned wood:

1. ....

2. ....

3. Operating the stove at the ragged edge of design parameters. Put another way too low a burn rate even if the cat is still active.

....

I am having a hard time envisioning the scenario where the burn rate is "way too low" while "the cat is still active".

What do you mean by this? I have heard others say that as long as the cat is active and within the acceptable range on the cat meter, the stove is being operated as it has been designed (assuming sufficient draft, dry wood, etc.).

My stove still has a smoke smell issue, but only when fully loaded and I damper it down for the long haul. I am pretty sure that I don't damper it too far down, at 3:30-4:00, because there are still plentiful red glowing coals. In other words, it still looks like a healthy burning stove. If I damper it down with a half load of wood or less, there is no smoke smell at all.

Anyways, I am awaiting a 2' piece of chimney pipe in the mail, which will erase any doubt of a draft problem. Also on order is an Amerivent stovetop adapter, to swap out the Duravent adapter that clearly doesn't fit well. After doing these two things, and cleaning up a sloppy weld on the inside of the seam of the stove collar, I will evaluate the smell issue again.

 

[kf6hap]

I am having a hard time envisioning the scenario where the burn rate is "way too low" while "the cat is still active".

What do you mean by this?

BTU-wise we can't know if the stove is being operated below the (given) low BTU number (parameter) indicated in the manual. With no way to measure it so we must go by operational observations that give indication, for example sticky creosote production, smoke smell, the firebox becoming heavily coated with combustion products , poor thermostatic control etc.

An active cat is a good indication things are going right but not absolute proof especially when running on the ragged edge.

 

[BKVP]

I suspect it has something to do with reusing the thermostat assembly on different models that require different calibrations. BK probably has a process in the factory where they heat up the thermostat assembly to a specific high temperature, and tune it's position to a specific %open that is different for each model.
If I had to guess it's tuned to a high temp position, where the stat is set to the highest position, and must close off to a certain minimum above a certain temperature (prevent overfire). The low position (cold closed) would end up where ever it is, based on the result of the high temp calibration.
The important thing is that you can set the intake to fully closed (minus the min FA hole). It seems like some people are tempted to modify non-BK stoves to further restrict intake air. On BK stoves this isn't necessary since the factory low is so low already, (even if it occurs higher than the min stat position). This is a confusing thing the manual doesn't handle well. The manual shows setting the stove to min on the stat, that would result in the air intake never opening at all even with a dying fire, and would leave a lot of un-burnt fuel.

@BKVP A BK factory tour/video would be interesting, the whole thermostat thing can't be much of a secret after all these years. But you wonder why no-one else seems to make a similar product. There must be something to the firebox design to that allows for precise control from the thermostat, maybe most other fireboxes hold too much heat causing fuel to be consumed quickly. Seems like a tricky balancing act to keep the firebox cool enough to go 24+hrs, but insulated enough that it doesn't extinguish at low burn rates.

Not going to happen, unless we exclude thermostat room! We make our own springs, which are different for each model. They are cut from raw stock, then formed to a specific number or portions of revolutions. Then baked at specific temps for a specific period of time. Now think on that for a moment, that after 40 years of refinement, it isn't easy to hit all four burn rates needed for EPA Certification tests.

 

[Highbeam]

Every single BK manual I have personally downloaded calls for 15' of stack above the collar.

My princess, 2012 model, only requires a 12' chimney. The current models require 15' according to their manual. Probably no actual changes to the stove but the manual was updated in response to field reports. Mine works great on a 12' stack but I would love to try adding a few feet. Unfortunately, I would then have to add a stupid looking and leak prone roof brace to support the stack!

 

[Highbeam]

Now think on that for a moment, that after 40 years of refinement, it isn't easy to hit all four burn rates needed for EPA Certification tests.

Has the EPA really required four burn rates for certification for the last 40 years? We all know that the answer is no. I wonder if finding an old "pre-EPA" spring would give our stats better performance!

Oooh, hot rod the stove. Still waiting for someone to replace their steelcat in a 30 box with a ceramic cat.

 

[BKVP]

Has the EPA really required four burn rates for certification for the last 40 years? We all know that the answer is no. I wonder if finding an old "pre-EPA" spring would give our stats better performance!

Oooh, hot rod the stove. Still waiting for someone to replace their steelcat in a 30 box with a ceramic cat.

Yes they have. Just landed in Denver to meet with state and fed regulators on testing with cordwood.

 

[kf6hap]

Still waiting for someone to replace their steelcat in a 30 box with a ceramic cat.

What gain are you hoping to achieve in going ceramic? I am of the understanding that steel is better in every department save somewhat shorter lifespan.

 

[Highbeam]

What gain are you hoping to achieve in going ceramic? I am of the understanding that steel is better in every department save somewhat shorter lifespan.

Cost. The ceramic is only 186$ delivered. Then, who knows what might change. Perhaps higher emissions and higher efficiency or not. Maybe the steel is really just to limit the liability of thermal shock. We know you'll save money but the question is what else.

 

[Highbeam]

Yes they have. Just landed in Denver to meet with state and fed regulators on testing with cordwood.

How could the EPA have required four different burn rates 40 years ago when there were no EPA certified stoves? That would be 1977. Didn't the first EPA certified stoves comes out well into the 1980s?

Cordwood testing is interesting. Whose cordwood? Our doug fir or the Oak of the east? I did notice that WA was only allowing wood boilers tested with doug fir cordwood and that there were actually some manufacturers that were approved. Still no warm air furnaces, not even the mighty kuuma, that have passed the test.

I'm really liking the fresh ceramic cat in my princess during this cold snap. So much control and so little visible smoke!

 

[kf6hap]

I'm really liking the fresh ceramic cat in my princess during this cold snap. So much control and so little visible smoke!

I like the no visible smoke part. How is light-off time? As fast as the steel cat?

 

[webby3650]

I like the no visible smoke part. How is light-off time? As fast as the steel cat?

I found that my ceramic cat fires up a little slower than the steel, but still usually only takes 20 minutes or so on a cold start to be active. Sometimes less.
The steel fired up quicker, but also fell out sooner, because it has less thermal mass. I prefer the ceramic cat.

 

[SuperJ]

I bet some digital controls with a cat temp sensor probe, draft pressure sensor, maybe some flue gas sensors, and a motorized air intake actuator all self powered by a thermal electric generator (like those bio light camp stoves) could really get things dialed in.
But I definitely appreciate the elegance of a pure mechanical solution.
Would be cool to see BK compete in that up coming wood stove competition in Washington. I think you need digital controls and electricity generation though to qualify.

 

[kennyp2339]

I bet some digital controls with a cat temp sensor probe, draft pressure sensor, maybe some flue gas sensors, and a motorized air intake actuator all self powered by a thermal electric generator (like those bio light camp stoves) could really get things dialed in.
But I definitely appreciate the elegance of a pure mechanical solution.
Would be cool to see BK compete in that up coming wood stove competition in Washington. I think you need digital controls and electricity generation though to qualify.

hmmm I'm trying to think of a name for that stove, BK Tesla or Westinghouse edition

 

[kf6hap]

I bet some digital controls with a cat temp sensor probe, draft pressure sensor, maybe some flue gas sensors, and a motorized air intake actuator all self powered by a thermal electric generator (like those bio light camp stoves) could really get things dialed in.
But I definitely appreciate the elegance of a pure mechanical solution.
Would be cool to see BK compete in that up coming wood stove competition in Washington. I think you need digital controls and electricity generation though to qualify.

And when the power goes off?? A few years ago, we were out for 12 days. Simple well designed and implemented mechanical controls are hard to beat. When a servo motor jambs up or an electronics assembly goes bad will you have a fire raging out of control? The more stuff included in a control system, the less reliable. The BK control has 3 moving parts. Ultra reliable long term. Perfected over the decades.

 

[SuperJ]

hmmm I'm trying to think of a name for that stove, BK Tesla or Westinghouse edition

I think it's inevitable, similar to fuel injection and emission controls on cars.
Gives new meaning to your stove going nuclear though!

Power can easily be generated by the stove itself from the heat. https://www.bioliteenergy.com/products/campstove-2

I agree, the current mechanical solution is elegant, and I don't want to take it for granted or wish it away.

 

[webby3650]

And when the power goes off?? A few years ago, we were out for 12 days. Simple well designed and implemented mechanical controls are hard to beat. When a servo motor jambs up or an electronics assembly goes bad will you have a fire raging out of control? The more stuff included in a control system, the less reliable. The BK control has 3 moving parts. Ultra reliable long term. Perfected over the decades.

Pretty sure last time I said this I got attacked! Someone even threw in the example of fuel injection...I agree with you completely.

From a home computer many might not know this, but if they work in this industry they do. Things are constantly getting more advanced in the hearth industry. In general lots of problems are arising, IPI, pellet stoves, and hybrid stoves are all problematic. Almost constant electronic malfunctions! Many manufacturers who were all about IPI are going back to standing pilot until the government forces their hand, hopefully they can figure it out by then...
Woodstoves are still consistent and reliable, I’d like to keep it that way.

 

[Ashful]

What gain are you hoping to achieve in going ceramic? I am of the understanding that steel is better in every department save somewhat shorter lifespan.

I have clogged one of my steelcats a few times each year with fly ash, only when running the stove wide open. The openings on a ceramic cat are larger, and I suspect less likely to clog.

That said, for the sake of thermal shock alone, I don't see myself making the switch. I run my stove on high, open the bypass, open the door, load more ice-cold wood, and then close the door and bypass, all inside of 60 seconds on a hot reload. I'm not dealing with the wait times required to repeat that procedure safely with a ceramic cat.

 

[webby3650]

I have clogged one of my steelcats a few times each year with fly ash, only when running the stove wide open. The openings on a ceramic cat are larger, and I suspect less likely to clog.

That said, for the sake of thermal shock alone, I don't see myself making the switch. I run my stove on high, open the bypass, open the door, load more ice-cold wood, and then close the door and bypass, all inside of 60 seconds on a hot reload. I'm not dealing with the wait times required to repeat that procedure safely with a ceramic cat.

Ahh! I don’t have any kind of special reloading procedure, I’ve never damaged one. I’m sure most of our customers don’t either, we rarely ever see a damaged cat on a BK.