# Automatic Controls for Wood Stoves



## RegencyNS (Jan 26, 2009)

This is one aspect of wood stoves that blows my mind. Wood Boilers and Wood furnaces have had automatic air and draft controls for years yet wood stove companies still don't make them.  Yes, I love the wood stove for its window and heat and so forth, but a little technology would never hurt.  I have heard the argument that it would be dangerous having automated air and draft control on a wood stove.  Thats a bunch of bolgne, like I said wood boilers and furnaces have had them for years, does that make them all unsafe?????????
It doesn't even have to be automated. Something to adjust the air and draft with a remote.  Yes, sometimes i like adjusting the wood stove manually and getting that great fire, but for instance, my wife is home right now trying to get the fire going good, adjusting everything, its -15 degrees celcius and no matter how many times I show her, she can never get it as hot as I can simply because I am used to the stove.  An automated air and draft control would be perfect, she could then just open the door and fill with wood.
GGRRRRRRRR...


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## roac (Jan 26, 2009)

Some stoves do have automatic air control. They use a mechanical control that opens and closes the air supply as the bi-metallic coil heats and cools. Quadrafire, Blaze King and others come to mind. It is a technology that has been around since the 70's.


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## North of 60 (Jan 26, 2009)

To explain how well mine works. If my stove is idling along at a constant temp with the stat satisfied and no visible flame in the stove and I turn the fans on, you will see stove temp drop, then a few swirls of ash in the stove with coals starting to glow brighter. Sometimes it will break into a flame again until the stove reaches that original temp again. If I wanted automation /digital control I would have bought a pellet stove. I cant trust or rely on that stuff in this climate.


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## North of 60 (Jan 26, 2009)

CZARCAR said:
			
		

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Hey Pooker, The answerer to that = CATALYTIC me thinx %-P


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## kenny chaos (Jan 26, 2009)

Here's a basic automatic air controller.  Doesn't work quite right but it proves there are people working on that idea.  I've read on here that someone's got a more complex prototype system that works well.  We'll all be watching.
http://www.youtube.com/watch?v=VPBqQb8fEQk&feature=related


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## downeast (Jan 26, 2009)

north of 60 said:
			
		

> Hey Pooker, The answerer to that = *CATALYTIC* me thinx %-P



Right Yukon !! 

Most of the cat stoves use a simple bimetallic coil for air control when the cat is "lit'. Examples: Woodstock, the older Jotul Firelight, and  ( forbid the mention ) VC cat stoves work well giving longer fires, more efficiency, cleaner burns than non-cats. We have one of each. We load the cat stove much less than our non-cat for the same species and space.

Any wood heating device will have some loading effort involved including boilers, and Masonry Frieplaces. If you want no effort, burn fossils for auto heat.


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## Todd (Jan 26, 2009)

The PE Summit and T-6 have EBT, so non cats can do it too.


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## Cearbhaill (Jan 26, 2009)

I would love, love, LOVE an air control/blower speed remote.
You'd just toss the wood in and not have to get up again.


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## daleeper (Jan 26, 2009)

downeast said:
			
		

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I don't believe the Woodstock has this type of air control, and "some" would be more accurate than "most".  I believe the Blaze King cat stoves, and some of the VC cat stoves (not the Dutchwest models) have bimetallic air control in current production, and that is it as far as I know.  Buck, Appalachian, and a few other current cat stoves are all manually controlled.  Someone please correct me if I'm wrong, as this is a feature I want, and would like to see more options in the market.


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## ControlFreak (Jan 26, 2009)

shawnmd said:
			
		

> This is one aspect of wood stoves that blows my mind. Wood Boilers and Wood furnaces have had automatic air and draft controls for years yet wood stove companies still don't make them.  Yes, I love the wood stove for its window and heat and so forth, but a little technology would never hurt.  I have heard the argument that it would be dangerous having automated air and draft control on a wood stove.  Thats a bunch of bolgne, like I said wood boilers and furnaces have had them for years, does that make them all unsafe?????????
> It doesn't even have to be automated. Something to adjust the air and draft with a remote.  Yes, sometimes i like adjusting the wood stove manually and getting that great fire, but for instance, my wife is home right now trying to get the fire going good, adjusting everything, its -15 degrees celcius and no matter how many times I show her, she can never get it as hot as I can simply because I am used to the stove.  An automated air and draft control would be perfect, she could then just open the door and fill with wood.
> GGRRRRRRRR...



Been there, done that...

Take a look here: www.inveninc.com
Also, take a look here: https://www.hearth.com/econtent/index.php/forums/viewthread/14421/#158782

Dan


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## Highbeam (Jan 26, 2009)

You're right daleeper, the stat is very rare in teh stove world. Even on Cat stoves they are very rare. The PE EBT system isn't really a stat as much as an idle control that holds a minimun temp only. 

Another member posted this negative... If you have a stat set to keep the stove temp at a minimum temp then on those overnight burns you will wakeup to a cold stove with no coals since the draft was flipped wide open by the stat. I really like being able to restart my warm stove in the morning from those smaller coals vs. start a cold stove from scratch.


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## savageactor7 (Jan 26, 2009)

Our last 2 Shenandoah's had a bi-metal thermostat that worked well but they would only hold up for a couple of years before they needed replacement. It controlled a little flapper valve that would let more air in to maintain a general temp like Low, Med and High. The stove was always smoking but I thought they both worked OK with the thermostat. 

I guess you had to be there but those newer pre EPA 'airtight' stoves were quite the step up if you burned with an older Franklin stove...that stove was a bottomless pit for wood. At the time we were both WOWed by the performance.


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## Stephen in SoKY (Jan 26, 2009)

Bimetal thermostats are one the big reasons they still sell so many Wonderwood stoves. Not much to look at, but extremely convenient & relatively efficient.


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## LLigetfa (Jan 26, 2009)

My RSF Onyx uses a bi-metal thermostatic air control and it works OK but if I want finer control, I adjust the wood loading or the doghouse air.

Back in the 70's I had a round, top-load stove with a bi-metal control that regulated a hinged flap.  It had a propensity to start bouncing up and down which in turn caused the stove to surge and puff like a dragon.  Sure got your attention.


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## RedRanger (Jan 26, 2009)

Why do I keep spelling automatic controls for wood stoves  YUPPIE??   Or should that be spelled "city slicker"?? :roll:


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## kenny chaos (Jan 26, 2009)

sonnyinbc said:
			
		

> Why do I keep spelling automatic controls for wood stoves  YUPPIE??   Or should that be spelled "city slicker"?? :roll:



Good question.  Why do you?


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## RedRanger (Jan 27, 2009)

kenny chaos said:
			
		

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Coming from a guy that can`t get his own house above 66 degrees--that kind of response doesn`t surprise me.

At least this time around you didn`t plagarize my name.  So I will try and correct my spelling and lets see--KCYUPPIE.!!

There we go, and I can see the temp rising already!!


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## rg500930 (Jan 27, 2009)

i took the ebt off my summit insert and installed a electronic controller hooked up to a car idle controller air valve.so when i have the insert running i set the damper to the burn rate i want.the electronic valve will be closed.as the insert cools the valve will open and give more air.it will give more even heat.or i can set the draft and when the temperature is steady i set the controller to the same temp.this way it will keep it that that temp.im still playing with it.seems to work good though.i can hear it clicking on and off.would like to find a larger air valve.nice having a digital readout also and cost me about $15.good old ebay.


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## North of 60 (Jan 27, 2009)

rg500930 said:
			
		

> i took the ebt off my summit insert and installed a electronic controller hooked up to a car idle controller air valve.so when i have the insert running i set the damper to the burn rate i want.the electronic valve will be closed.as the insert cools the valve will open and give more air.it will give more even heat.or i can set the draft and when the temperature is steady i set the controller to the same temp.this way it will keep it that that temp.im still playing with it.seems to work good though.i can hear it clicking on and off.would like to find a larger air valve.nice having a digital readout also and cost me about $15.good old ebay.



  What are you using for a power supply? Where did your EBT get its air from before? Also what and where are you using for a temp reference?


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## rg500930 (Jan 27, 2009)

power supply for the air valve?just a 12v power supply say off of a cordless phone.the EBT has its own air intake into the stove.i didnt like how the EBT valve worked.


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## Heem (Jan 27, 2009)

Cearbhaill said:
			
		

> I would love, love, LOVE an air control/blower speed remote.
> You'd just toss the wood in and not have to get up again.



could easily be built with a servo motor and some linkages depending on if yours is in/out or right left... hmmmmmmmmmmm


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## rg500930 (Jan 27, 2009)

the controller is 120v.what do you mean by temp reference.most of the time i just have the valve set to open at 400f


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## North of 60 (Jan 27, 2009)

rg500930 said:
			
		

> the controller is 120v.what do you mean by temp reference.most of the time i just have the valve set to open at 400f



I am just trying to figure it out. There must be a relay of some sort if the components are from an auto. The main controller is 120V? 12V DC would be your required output. The temp reference would have to be located somewhere on the stove and would be rated at some higher temp. The existing EBT I thought was modulating. Not on/off as an air valve would be. Just curious.
Any photos?


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## rg500930 (Jan 27, 2009)

yes theres a relay built into the controller.if i remember its something good up to 2 amps.the transformer is in milliamps so i dont have to worry about burning anything out.the airvalve is a 3 wire.its like a soledoid.one wire opens the valve,one closes.the other negative.the  EBT is at the bottom of the firebox.under the firebrick,ashes etc.i watched the flap move.long story short it would work if it was at the top of the box not at the bottom.as for variable its a small hole the size of your small finger so i dont think would make much of a difference.i ground the ebt hole a little bigger.can only grind it so big because its welded to a small pipe inside.was thinking of attaching a second air valve and have that operate off of the controller/relay alarm side.the probe i have it above the front of the door.so say i have the stove running at 500f as it cools to 400 the valve opens and lets more air in.brings the temp back up.i can hear it clik on and off a few times.and just for info that small air hole has more of an affect when the temp is higher.so say if i had it open at 200f it doesnt do much.ill get some photos tomorrow.i didnt want anything that made a drastic affect on the stove just incase something happens with it while im away.like power goes out while controller is on high(if i had something that let alot of air in)


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## North of 60 (Jan 27, 2009)

Thanx for the info and explanation rg500930. If the air valve is a normally closed valve than you should have no worries. The temp sensor must be adjustable and sounds pretty unique.


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## begreen (Jan 27, 2009)

Todd said:
			
		

> The PE Summit and T-6 have EBT, so non cats can do it too.



As did all the old VC non-cat stoves I think.


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## kenny chaos (Jan 27, 2009)

While we're at it, why not add an air to water heat exchanger to the flue and draw off the rest of the flue heat to heat a space heater and dhw.  Add a draft fan and vent it through some 2"pvc out the wall?


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## kenny chaos (Jan 27, 2009)

But if we try to keep things in perspective and be a little pragmatic about the whole thing; a woodstove is just a space heater, albeit a very expensive and time consuming one.  Heating very large spaces and whole houses should be more the exception than the rule and even then, fraught with frustrations of moving and controlling the heat.  For anything more than use as a "accept it as it is" space heater, maybe existing gasifier boilers with a decorative cover and a large glass door would suit those desiring the ambiance of the flames and the automation and proper distribution of the heat.


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## WES999 (Jan 27, 2009)

I have given some thought to making an electronic damper control. I was thinking of using a temp control with proportional output and a HVAC proportional damper control. Both off the shelf components. I think one of the main issues is the large number of variables, amount of wood, wood type (dry wet) hot stove cold stove etc etc.
The only input sensors would be flue temp and stove top temp. I may be difficult come up with control method that would work in every situation. I think it would be an interesting project and may give it a try someday.


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## Heem (Jan 27, 2009)

WES999 said:
			
		

> I have given some thought to making an electronic damper control. I was thinking of using a temp control




I was even thinking simpler - just a control I can operate from my butt. I mean the couch.


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## EddyKilowatt (Jan 27, 2009)

The Condar Stovetemp Thermostat

A cute little bimetal gadget from the early '80s that (I think) replaced the draft control on draft-wheel stoves.  Can't find a pic online right now, but they turn up on EBay from time to time, and go for pretty stiff prices when they do.



It's probably just me (I design electronic stuff for a living), but I wouldn't want anything more than a simple bimetal or pneumatic temperature/draft feedback control on a wood stove.    Horses for courses.

Eddy


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## mellow (Jan 27, 2009)

EddyKilowatt said:
			
		

> The Condar Stovetemp Thermostat
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> A cute little bimetal gadget from the early '80s that (I think) replaced the draft control on draft-wheel stoves.  Can't find a pic online right now, but they turn up on EBay from time to time, and go for pretty stiff prices when they do.
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Interesting Layout:


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## rg500930 (Jan 28, 2009)

heres that controller and air valve.so if i set the temp at 400f.anything above that the air valve is closed.anything below it will be opened.just something simple i rigged up to play with.


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## semipro (Jan 28, 2009)

ShawnMD, I'm with you.  I don't understand why thermostatic controls aren't a more common feature on stoves.  I've had a VC Encore and a Sears wood burning appliance that both had thermostatic air controls.  They worked great.


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## MaineMike100 (Jan 28, 2009)

I agree they should be on more stoves, but as someone said earlier, bi-metallic thermostats have been around since the 70's.  I have an unused wonderwood in the shed, and an old oval ashley at a camp which both have so called "automatic draft".  Both stoves were purchased before 1980.


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## kenny chaos (Jan 28, 2009)

I had the bi-metallic thermostats on two Riteway 2000's from the early 70's.  The problem with them on those stoves was that the thermostat was always trying to catch up.  When the temp dropped, the door would start to open and the fire may or may not have taken right off.  The thermostat was still slowly opening adding even more air, and more air, and more air, until it read that it was too hot and started to close, and closed a little more, then a little more.  I had to watch it constantly with a full firebox which pretty much negated its usefullness.
I have thought before about how much better it would be on my Liberty because it doesn't react so quickly to small air changes and unless the flue by-pass is open, it's pretty much impossible to over fire.  It's basically a whole lot more stable than the old stoves.
Now don't tell anyone but I still have one of the Riteways in the front room and if you guys keep going on like this, I think the thermostat would fit nicely on the Liberty with very little work and no major intrusions.
Stay tuned and I'll try to get a picture of the Riteway with the wife's cell phone when she gets home.
Ken


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## kenny chaos (Jan 28, 2009)

I got the picture.  Here's a Rite Heat Regulator which dials from 0-15 and in the picture is set on 15.


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## MaineMike100 (Jan 28, 2009)

Similar to the old wonderwoods with a cable to open the draft door.


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## rg500930 (Jan 29, 2009)

or something that measures the cfm of air entering the stove


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## Lumber-Jack (Jan 29, 2009)

How about a Computer Controlled Wood Stove???


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## Wet1 (Jan 29, 2009)

I agree a computer (electronics) could more accurately and efficiently run a stove, but I'm not so sure this is something I'd want... Mainly because of safety, but also because I want my stove to be independent from the grid.


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## savageactor7 (Jan 29, 2009)

Wet1 said:
			
		

> ... but also because I want my stove to be independent from the grid.



Bingo! we have a winner...that is reason #2 why we have a wood stove.


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## Stephen in SoKY (Jan 29, 2009)

What are you finding objectionable with the Bi-metal thermostats that causes you to try & replace them? It's been my experience thay do the job beautifully, but perhaps I'm overlooking something?


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## Wet1 (Jan 29, 2009)

I was thinking more along the lines of a giant hopper for splits/rounds, kind of like on a pellet stove.


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## BrotherBart (Jan 29, 2009)

kenny chaos said:
			
		

> I got the picture.  Here's a Rite Heat Regulator which dials from 0-15 and in the picture is set on 15.



Ought to work fine. Ya just put a pipe on the OAK inlet of a new wood stove, mount that stat on the side of the firebox and the flap where it opens and closes the end of the pipe.


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## kenny chaos (Jan 30, 2009)

BrotherBart said:
			
		

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Right now I set the air when the stove top is at 600 degrees, for these cold nights.  It holds there and eventually drops lower and lower.  I'm afraid that with a auto damper control set at a certain temp that I won't have much, if anything, left in the morning.
Any opinions? (stupid question but I want to hear them.)


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## North of 60 (Jan 30, 2009)

kenny chaos said:
			
		

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Sooooo are ya just burnin for looks. If you need the heat then you need it. Ive got no problem with leftovers in the AM on our cold nights. If your getting 8hrs of beauty sleep than thats a shorter burn on a good heat setting. If you want a longer burn then that just set the stat lower. Remember on the BK low is only 350f for most of the burn. You will get 8hrs @ 500 with your hardwood no problem. Thats from the little Princess with 6" flue.
N of 60


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## savageactor7 (Jan 30, 2009)

Stephen in SoKY said:
			
		

> What are you finding objectionable with the Bi-metal thermostats that causes you to try & replace them? It's been my experience thay do the job beautifully, but perhaps I'm overlooking something?



I may have given that impression but I didn't mean to...those thermostats worked well and were easy to change. I'm sure that with today's tech they could be made to last a few years longer. 

As to why no more thermostats I suspect government regulations. When you see experienced stove companies suddenly abandon things like flue dampers and thermostats the answer must be in the regulations...

...and as payback for their meek compliance the regs were modified enough to legally advertise a 12 hour burn time for a non CAT stove... LOL!


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## 21acrewoods (Feb 5, 2009)

I like the idea of good burning with no electric!!


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