Smart Stove Controller on Blaze King

[turbojoe]

I used to service fire alarm systems. I saw a Johnson controls guy program one like this to open a boiler valve by the stem...... I think he had to remove the default range stop set screws but it worked.

It was only a 3 hour install, but the right one of these would turn a BK install into a 1 hour deal..
Thanks for sharing.

 

[bobdog2o02]

It was only a 3 hour install, but the right one of these would turn a BK install into a 1 hour deal..
Thanks for sharing.

Your welcome.

 

[turbojoe]

Over control, not an easy project... Haven't given up yet but not sure this controller has the necessary parameters to work the way I want on this stove. Plenty of handy features, works decent considering it is designed for a tube stove. Still tuning, gota mess it up to get it better...lol..
Basically, System works good, trying to get repeatability. It will amaze me on one burn, then leave me thinking WTH on the next...lol, Now I am starting to cheat parameters to adjust things I wish had there own settings.

 

[Oldman47]

Check the time constant you are using turbojoe. It looks to me like you are getting into a cyclic situation by allowing the controls to respond too quickly. A longer time constant should smooth that out.

 

[blueguy]

I'm curious if the bimetallic coil interferes with the controller at all?

 

[turbojoe]

I'm curious if the bimetallic coil interferes with the controller at all?

I thought about that too, I have been running it without the cover on to watch the air valve. I'm not seeing any issue with the spring trying to work against the controller.
It takes a pretty big temp swing before the bimetal spring even moves. Probally why it works....lol a slower control loop

 

[turbojoe]

Check the time constant you are using turbojoe. It looks to me like you are getting into a cyclic situation by allowing the controls to respond too quickly. A longer time constant should smooth that out.

The loop is too fast for sure, unfortunately there is no adjustment for this. I have been cheating another adjustment to slow down the loop. It helps some but would require a perimeter adjustment every time I change temp settings. And this adjustment limits the draft opening past 50%, I really liked it opening as the temps dropped near end of cycle, Burns down the coals and extended the burn time.

 

[blueguy]

I thought about that too, I have been running it without the cover on to watch the air valve. I'm not seeing any issue with the spring trying to work against the controller.
It takes a pretty big temp swing before the bimetal spring even moves. Probally why it works....lol a slower control loop

I wonder if you could replace the stat with the coil for one without, and just have the controller control it all?

 

[jeff_t]

I wonder if you could replace the stat with the coil for one without, and just have the controller control it all?

This makes sense for a truly 'smart stove'. Total control of the incoming air.

Is it precise enough to eliminate the hole in the butterfly?

 

[turbojoe]

I wonder if you could replace the stat with the coil for one without, and just have the controller control it all?

Not sure if there is a BK stat without the spring.
My original design was to use a seperate air valve from the BK valve and just turn the BK stat to 3.5, basically holding it open. I'm glad i didn't waste the time to fabricate that up and desided to go with an easy install to see if this controller would work. The control loop in the Smart Control is set up completely wrong for a Cat stove. I was able to fudge a bunch of wrong peramiters to get a decent burn at 300dF.
400dF was an epic fail !
Back on the trusty BK stat.

 

[turbojoe]

This makes sense for a truly 'smart stove'. Total control of the incoming air.

Is it precise enough to eliminate the hole in the butterfly?

Not even close. The minimum air hole saved this things ass.lol.. It is always trying to control to zero, not looking for a set point. The best it ran was at 0% air valve :O
It has a few real nice features. It will open the air to 100% for a set amount of time after adding wood then ramp down the air, and would also open the air back up at end of burn cycle to burn down coals and extend the heat cycle. So basically, the first 10 minutes and the last few hours are good. Just need to fix the other 8+ hours...lol

 

[rdust]

It takes a pretty big temp swing before the bimetal spring even moves. Probally why it works....lol a slower control loop

I'm sure BK has done a lot of R&D over the years, while the stat is far from perfect it works pretty well. Others in the past have pointed out/complained about the "lazy" stat. My personal thought on the subject has always been it needs to react somewhat slow or it's going to be like a dog trying to catch it's tail. If the stove had some type of draft assistance similar to a pellet stove I could see it responding better to quick changes. I'm ok with keeping it simple.

 

[turbojoe]

Not hating on Dan at all here, I was trying to do something that it just wasn't designed to do. After gaining a better understanding of his loop i realize the gain changes i need, or think i need are not feasible with this type of loop. I will try a different burn strategy first and then move on to making a set point controller. I'm not real confident closed loop is possible with so many changing variables.

 

[turbojoe]

I'm sure BK has done a lot of R&D over the years, while the stat is far from perfect it works pretty well. Others in the past have pointed out/complained about the "lazy" stat. My personal thought on the subject has always been it needs to react somewhat slow or it's going to be like a dog trying to catch it's tail. If the stove had some type of draft assistance similar to a pellet stove I could see it responding better to quick changes. I'm ok with keeping it simple.

You hit the nail on the head my freind

 

[mellow]

Slow air intake changes seems to be a common thing I hear when it comes to cat stoves, tube stoves are more forgiving. That was one of the reasons I didn't get the smart stove for my cat stove a while back, Dan works with tube stoves and I honestly wasn't sure how much better you could make a burn in a cat stove.

Now the Jotul 450 I briefly had, that would have worked great on it, simple easy single control, but you know what they say about once you go cat....

 

[turbojoe]

Back on the bimetal. BK wins this battle !!
Though the Smart Stove controller packs plenty of cool features, it's control loop just won't work as is on a Cat stove. Working with Dan on making a few tweeks to his code.

Am also playing with building my own controller.

I am still running the temp control knob with a servo, it's just connected to a manual servo driver with 10 set points. Since mine is a corner install, i was always trying to get my head back there far enough to read were i had it set at. My stove has always run in a very small range 1.5 to 2.0. I found myself fidleing around trying to get it just over or just under 1.5.... kinda like it needs 1.4,1.5,1.6 ect.
I have that kind of resolution now.

 

[bobdog2o02]

Havn't given up, am going to builf my own controller that i can code how ever i see fit

This sounds like an arduino project now......

 

[turbojoe]

This sounds like an arduino project now......

Alot of bang for your $$$ with there boards.

 

[bobdog2o02]

I have the same stove as you, feel free to pm me for my phone number. I would love to help out with this project. I really would like something that can open the air to 80%ish when the STT drops below 300.

 

[turbojoe]

I have the same stove as you, feel free to pm me for my phone number. I would love to help out with this project. I really would like something that can open the air to 80%ish when the STT drops below 300.

I really liked that feature with Dan's controller. It helped burn down the coals. I also liked the add wood timer. It would command the draft to 100% for a set amount of time after adding wood.
I have mixed feelings about close loop controlling this stove by temp. I doesn't like the air to be modulated. What i learned so far is modulating the draft to hold temps steady doesn't net you an optimal burn.
A steady air set point does a better job of combusting the wood.
My thought now is to run it at various set points and note the approx. temp that nets. Kinda like we do now, I know 1.5 will get me about 350/400 STT, I do realize this changes with fuel loads and draft conditions.
Maybe give it a draft set point and allow 5/10% adjustment, until you drop below a certain temp threshold that would signal coaling stage and begin to open the draft.
Just thinking out loud...lol
Sounds good Bob, I stink at coding. I do have plenty of engineering support at work for that but.... these guys are smart as hell, but have never seen a wood stove They sometimes act like I’m controlling an engine. I already do that, that's easy compared to this. I find myself looking at boards that can be programmed by USB in Windows. Not sure those are the best option

Joe

 

[turbojoe]

This sounds like an arduino project now......

Look what you started bobdog
An Arduino 2560 mega with a LCD/Keypad shield.
Should have it figured out in a few years. ..lol

 

[turbojoe]

Introducing the Turbo Joe Dumb Stove Controller. Lol
I know.... why???
I had a hobbie servo tester, my stove already had a servo and i had an extra hour. lol
Mine is a corner install and my big head is always trying to look back there to make that fine adjustment it probably doesn't need...
My stove pretty much runs from 1.5 to 2 0, other than 100% to get a new load going and burn down coals.

 

[bobdog2o02]

Is that the mounting plate from the "Smart Stove"?

 

[turbojoe]

Is that the mounting plate from the "Smart Stove"?

Don't tell Dan...lol
It looks like we are going to try to move forward with the Smart Stove Controller . We are on a brake from that project for a bit.So i left the remote mount up.
My next feat will be to get the Arguino to move that servo.
I have it working with a reostat but am trying to write code for push button open and close with LCD position read out Should have V1.0 ready by 2017....lol

 

[bobdog2o02]

After push button is working you got it made, just assign input thermocouple temps to activate whichever button.