Searching for a good DIGITAL stove thermometer

[Gooserider]

I've been reading many of the posts here, and am very impressed with the quality of the information on the board, but I haven't really seen anyone talking about the problem I've been having.

We currently use one of those standard magnetic surface dial thermometers on our stovepipe. However where it's located it is very hard to read because of the way the room is often lit. I have enough trouble encouraging the GF to keep an eye on the stove, it would be easier if we could see what it is doing without straining.

We would really like to update it with a LARGE digital display thermometer (~1" high digits), preferably with a back-light, that we can read from across the room.

The "ideal" unit might also have a user settable alert (or alerts) for high temperatures. Power can be either AC or Battery (battery backed AC would be the real ideal...) If it had a way to output to my Linux PC via Ethernet, that would also be nice, but is kind of overkill. I could potentially use multiple sensor locations, but again that is not needed for other than curiosity. Cost is mildly an issue, I'm willing to pay a reasonable sum but considering that things like digital cooking thermometers can be had for well under $20 I'm not sure that what I'm after should cost much over $50, certainly not over $100...

(I'm also enough of an electronics person that I could probably do minor mods to fix things like power and backlighting if the other features I wanted were there.

I've been searching the web, and all that I've been able to find is the Condar 9-86 or 9-88, neither of which looked all that close, and from some of the discussions I've seen here, it looks even less appealing. I'd like better than 50* increments, and I'm not interested in something that turns itself off regularly. I'm also not all that attracted to the idea of a hand-held IR thermometer - the GF looses the remotes for her TV on a regular basis...

I've also found a few ultra high precision lab type instruments, but they are expen$ive, and again I'm not sure they have a large enough display.

Can anyone give me a suggestion of where to go for something like this? If I were to look for a thermometer that was intended for a different application, what kind of temp range would I need to worry about (assume a flue probe) and what would I need to do to make the probe fire proof?

Thanks,

Gooserider

 

[velvetfoot]

I have a VDO exhaust gas temperature meter on my VW. I think it goes to 1400F. Even if you did adapt one, it might not be cheap unless maybe you got one used. The thermocouple would have to be installed in the pipe I guess. You wouldn't drill the stove and thread it in for interior stove temps, or would you?? The good gauges have alarms. They all are lighted. You'd need 12 volt power.

 

[Jay H]

I have a Condar 3-19 (as you may have seen my thread). It's not the one with the fancy colors but I sit about a good 12 feet from my stove and I can eyeball it and gauge roughly where it is... My fluepipe is black and the pointer on the thing is white and I know where the 'detents' are, aka the markings. I can definitely see whether it is closer to 400 than say 900degs...

If you are handy with electronics, perhaps you can build a small alarm that will be triggered by the pointer closing a small circuit hooked up to a battery and a speaker...

Jay

 

[Gooserider]

Thanks for the replies - it sounds like none of the manufacturers really seems to be addressing this market, which seems odd, but I guess that's the way it is.

It seems to me like there are so many advantages to a digital unit, I don't know why anyone would want one of those dials - I'd be surprised if they had anywheres near the accuracy and they certainly are harder to read.

If I find anything, I will let people know for sure.

Gooserider

 

[cbrodsky]

Thanks for the replies - it sounds like none of the manufacturers really seems to be addressing this market, which seems odd, but I guess that's the way it is.

It seems to me like there are so many advantages to a digital unit, I don't know why anyone would want one of those dials - I'd be surprised if they had anywheres near the accuracy and they certainly are harder to read.

If I find anything, I will let people know for sure.

Gooserider

I have been thinking about this myself and there are some very good options out there. The Condar is interesting, but seems a bit overpriced to me given the lack of features.

You need a "thermocouple" unit that can withstand high temperatures and read from a remote sensor that you plug into the main unit. This will let you safely mount the display away from the heat of the stove.

Thermocouple probes generally have a letter designation to define their temperature range. A type "K" is good up to 2000 F - can use it for flue gases, for example. They also come in flexible thin wire types that can be tucked in almost anywhere. They will also respond nearly instantly thus giving you much faster feedback then the stovetop thermometer. I know another Woodstock owner finds an internal thermometer on their cat lets them engage even earlier than what the surface unit suggests, getting even more efficiency.

I have seen units advertised for ~$100 that not only read temperature, but allow you to monitor two temperatures, along with alarm setpoints, and data logging. This could let you do a lot more than just see a temperature. Ideally, I'd like a unit watches the internal temperature and beeps when it's time to engage the catalyst. (or adjust air controls for the non-cat types). Similarly, it could alarm if you get too hot, and even tell you after the fact if you overfired or had a chimney fire while you were away and wouldn't otherwise know.

Take a look on e-bay and you'll find quite a few. One example of a simple unit for $25:

http://cgi.ebay.com/Cen-Tech-Digita...ryZ50974QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I also found some reasonably priced units with many more features here:

(broken link removed to http://www.ambientweather.com/diprhaheth.html)

Still trying to decide on a unit.

Given how cheap the sensor technology has gotten, the holy grail would be to then tie it into a mechanical actuator on the air control lever. With a simple program, you could have it constantly optimize burn rate by watching cat/flue temps and adjusting the air temperature accordingly to hit peak efficiency, maximize burn time, and avoid any risk of overfiring or overdamping.

-Colin

 

[cbrodsky]

ps -

As for getting the sensor in, the wires are thin enough on many thermocouples that as long as you had high temperature sheathing, you could sandwich them in any available gasket. On a Woodstock, the entire lid lifts to enable access to the catalyst, but is also very heavy due to the soapstone. I figure I'll just tuck the wire in through the gasketed seal and snake it exactly where I want it.

Some other people have drilled pinholes in stovepipes; you could also probably tuck a wire through a stovepipe joint as long as you were careful about it when putting it together.

-Colin

 

[BrotherBart]

Get a pyrometer. Lots of them out there. Ain't cheap but they do what you want.

 

[MikeS]

I am just setting up jotul with cat (model series 8 from 1997).
I was interested in differential cat temp gauge, too.
I was considering making unit powered by thermoelectric effect (like those stupid fans that spin from the heat of the stove top).
I wanted Cat in, Cat out and maybe one other temperature to use (stack middle or top?).
I also considered some LED "bar graph" assemblies that have yellow (cool) green (good) and red (overfire). A pair of green lights means the cat is happy.
another trick could be a bargraph for differential- yellow (match or out lower than in), Green (out hotter than inlet), red (everything melting down, check stack for burning cat particles fireworks show).

Poster suggested ethernet interface (web server). I have done this for other application, but it is barely worth it for $100. I would have to sell 30 to 50 of them to think about it. At this level of comlexity, I would add differntial pressure to quantify the draft (so this would require a hole in the stack and a somewhat carefully installed tap). The webserver could be WiFi, so no cable needed. I have not yet considered how much silicon will be required to make the thermoelectric power supply assuming the WiFi and webserver running. My first guess is that it should be similar to the motor in the fan, and not more than 5 of the fan things in a worst-case scenario. I can obtain the very small, Type K TC with mineral-fiber insulation for pass-through of a gasket. in my case, I will pass through the cat-access panel.

Any ideas out there? I have used pyrometers for diesel engine and catalyst maintenance applications and do not want this rig on my stove (ulness they got them with thin sensors nowadays). the ones I used were INDUSTRIAL and had maybe 3/16" spring-wrapped probes on metalic tubing. I want something slick-maybe even just single-lamp multi-color leds--inlet green at 500F or up, and outlet green if hotter than inlet. Otherwise: inlet yellow under 500 or red over 1500 outlet yellow if under 500 or if over 500 but lower than inlet, red over 1500. or something similar.

someone make this for me so i don't have to.

 

[babalu87]

Get a black magic marker and put a thick line at the ideal temperature you want the stove to run at.

Our thermometer has a yellow, orange and red background.
If its orange its good to go.

 

[Gooserider]

Well part of the problem we have with a dial thermometer is that it's hard for us to see unless right on top of the stove - If we could get something digital, then we could put the display on the chimney or wall where it would be easy to see and read from across the room. Better yet, If I could get an ethernet interface (cat5 preferred, as I don't like wireless) then I can read the display from my PC in another room.

A higher contrast dial would be better than what we currently have, but really wouldn't do what we need.

Gooserider

 

[Kenny1]

Thanks for the replies - it sounds like none of the manufacturers really seems to be addressing this market, which seems odd, but I guess that's the way it is.

It seems to me like there are so many advantages to a digital unit, I don't know why anyone would want one of those dials - I'd be surprised if they had anywheres near the accuracy and they certainly are harder to read.

If I find anything, I will let people know for sure.

Gooserider

I have been thinking about this myself and there are some very good options out there. The Condar is interesting, but seems a bit overpriced to me given the lack of features.

You need a "thermocouple" unit that can withstand high temperatures and read from a remote sensor that you plug into the main unit. This will let you safely mount the display away from the heat of the stove.

Thermocouple probes generally have a letter designation to define their temperature range. A type "K" is good up to 2000 F - can use it for flue gases, for example. They also come in flexible thin wire types that can be tucked in almost anywhere. They will also respond nearly instantly thus giving you much faster feedback then the stovetop thermometer. I know another Woodstock owner finds an internal thermometer on their cat lets them engage even earlier than what the surface unit suggests, getting even more efficiency.

I have seen units advertised for ~$100 that not only read temperature, but allow you to monitor two temperatures, along with alarm setpoints, and data logging. This could let you do a lot more than just see a temperature. Ideally, I'd like a unit watches the internal temperature and beeps when it's time to engage the catalyst. (or adjust air controls for the non-cat types). Similarly, it could alarm if you get too hot, and even tell you after the fact if you overfired or had a chimney fire while you were away and wouldn't otherwise know.

Take a look on e-bay and you'll find quite a few. One example of a simple unit for $25:

http://cgi.ebay.com/Cen-Tech-Digita...ryZ50974QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I also found some reasonably priced units with many more features here:

(broken link removed to http://www.ambientweather.com/diprhaheth.html)

Still trying to decide on a unit.

Given how cheap the sensor technology has gotten, the holy grail would be to then tie it into a mechanical actuator on the air control lever. With a simple program, you could have it constantly optimize burn rate by watching cat/flue temps and adjusting the air temperature accordingly to hit peak efficiency, maximize burn time, and avoid any risk of overfiring or overdamping.

-Colin

Hiya Colin:

Lets go one better. Instead of just adjusting the air control lever, lets add a few more features.

With a remote room sensor, we could also add the room temp parameter to the equation (we may need to add a small 8 bit micro to manage this).

Now, if we had a way to automatically add fuel to the fire, this would allow for more automation. I think we could do that if we made the wood small (so that it would flow). Having a uniform fuel size would greatly simplify things. We could then add a storage tank to the stove, and some sort of system to automatically feed into the burn chamber.

To improve efficencies, we may wish to add a fan to force air into the combustion area. If we have a fan blowing into the fuel, we could also add an auto start feature if we could heat the air we are driving into the burn chamber hot enough.

If we are going to do that, maybe we could add a heat exchanger as well (and of course, a small distribution fan). Imagin the efficencies such a stove could offer!

Now, with a fairly simple program, we could measure the room temp, and automatically have the stove adjust for changing conditions. We should probably add a small set of user controls and some indicators somewhere to the stove (we would not need that much of a user interface).

I think for such a system to work, we would probably have to get some industry standards for the fuel.


Anyway, just some random thoughts.

Stay warm


Kenny

 

[Roospike]

Thanks for the replies - it sounds like none of the manufacturers really seems to be addressing this market, which seems odd, but I guess that's the way it is.

It seems to me like there are so many advantages to a digital unit, I don't know why anyone would want one of those dials - I'd be surprised if they had anywheres near the accuracy and they certainly are harder to read.

If I find anything, I will let people know for sure.

Gooserider

I have been thinking about this myself and there are some very good options out there. The Condar is interesting, but seems a bit overpriced to me given the lack of features.

You need a "thermocouple" unit that can withstand high temperatures and read from a remote sensor that you plug into the main unit. This will let you safely mount the display away from the heat of the stove.

Thermocouple probes generally have a letter designation to define their temperature range. A type "K" is good up to 2000 F - can use it for flue gases, for example. They also come in flexible thin wire types that can be tucked in almost anywhere. They will also respond nearly instantly thus giving you much faster feedback then the stovetop thermometer. I know another Woodstock owner finds an internal thermometer on their cat lets them engage even earlier than what the surface unit suggests, getting even more efficiency.

I have seen units advertised for ~$100 that not only read temperature, but allow you to monitor two temperatures, along with alarm setpoints, and data logging. This could let you do a lot more than just see a temperature. Ideally, I'd like a unit watches the internal temperature and beeps when it's time to engage the catalyst. (or adjust air controls for the non-cat types). Similarly, it could alarm if you get too hot, and even tell you after the fact if you overfired or had a chimney fire while you were away and wouldn't otherwise know.

Take a look on e-bay and you'll find quite a few. One example of a simple unit for $25:

http://cgi.ebay.com/Cen-Tech-Digita...ryZ50974QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I also found some reasonably priced units with many more features here:

(broken link removed to http://www.ambientweather.com/diprhaheth.html)

Still trying to decide on a unit.

Given how cheap the sensor technology has gotten, the holy grail would be to then tie it into a mechanical actuator on the air control lever. With a simple program, you could have it constantly optimize burn rate by watching cat/flue temps and adjusting the air temperature accordingly to hit peak efficiency, maximize burn time, and avoid any risk of overfiring or overdamping.

-Colin

Hiya Colin:

Lets go one better. Instead of just adjusting the air control lever, lets add a few more features.

With a remote room sensor, we could also add the room temp parameter to the equation (we may need to add a small 8 bit micro to manage this).

Now, if we had a way to automatically add fuel to the fire, this would allow for more automation. I think we could do that if we made the wood small (so that it would flow). Having a uniform fuel size would greatly simplify things. We could then add a storage tank to the stove, and some sort of system to automatically feed into the burn chamber.

To improve efficencies, we may wish to add a fan to force air into the combustion area. If we have a fan blowing into the fuel, we could also add an auto start feature if we could heat the air we are driving into the burn chamber hot enough.

If we are going to do that, maybe we could add a heat exchanger as well (and of course, a small distribution fan). Imagin the efficencies such a stove could offer!

Now, with a fairly simple program, we could measure the room temp, and automatically have the stove adjust for changing conditions. We should probably add a small set of user controls and some indicators somewhere to the stove (we would not need that much of a user interface).

I think for such a system to work, we would probably have to get some industry standards for the fuel.


Anyway, just some random thoughts.

Stay warm


Kenny

********** :lol: *********** We will need a special name for this kinda of stove ,
We could call it a ......................... " _ _ _ _ _ _ stove "

 

[mikenr1c]

A big dial or digital display would be great. The little indicator on top of the stove requires me to walk over there.

Battery backup so it would work when the power is off.

Definitely an auxiliary output so it could activate a fan.

I would like to have an alarm that sounds when the stove is too hot. Maybe even an assortment of beeps that would let me know what the stove temperature is. Short and not loud and spaced about every two minutes so they are not "too" annoying.

I would be happy to join others that was interested in fabricating similar devices this winter! I can help with the design.

Email me if you are interested.

regards, Mike

 

[cbrodsky]

Hiya Colin:

Lets go one better. Instead of just adjusting the air control lever, lets add a few more features.

With a remote room sensor, we could also add the room temp parameter to the equation (we may need to add a small 8 bit micro to manage this).

Now, if we had a way to automatically add fuel to the fire, this would allow for more automation. I think we could do that if we made the wood small (so that it would flow). Having a uniform fuel size would greatly simplify things. We could then add a storage tank to the stove, and some sort of system to automatically feed into the burn chamber.

To improve efficencies, we may wish to add a fan to force air into the combustion area. If we have a fan blowing into the fuel, we could also add an auto start feature if we could heat the air we are driving into the burn chamber hot enough.

If we are going to do that, maybe we could add a heat exchanger as well (and of course, a small distribution fan). Imagin the efficencies such a stove could offer!

Now, with a fairly simple program, we could measure the room temp, and automatically have the stove adjust for changing conditions. We should probably add a small set of user controls and some indicators somewhere to the stove (we would not need that much of a user interface).

I think for such a system to work, we would probably have to get some industry standards for the fuel.


Anyway, just some random thoughts.

Stay warm


Kenny

********** :lol: *********** We will need a special name for this kinda of stove ,
We could call it a ......................... " _ _ _ _ _ _ stove "

This is awesome - and the best part that Kenny missed is that we could make this newfangled miniature fuel out of free waste products from wood processing facilities. Then we can charge whatever the market will bear right in step with the skyrocketing price of all other commercial fuels and tell people it's, um, transportation and shipping!

After spending $2-$3K on one of these _ _ _ _ _ _ stoves, you'd be an idiot to not use it, so you gotta keep that thing working, buy that special fuel and tell everyone how much money you're "saving" right?

-Colin

 

[Roospike]

He(( of an idea .....................I think were on to something !

 

[cbrodsky]

A big dial or digital display would be great. The little indicator on top of the stove requires me to walk over there.

Battery backup so it would work when the power is off.

Definitely an auxiliary output so it could activate a fan.

I would like to have an alarm that sounds when the stove is too hot. Maybe even an assortment of beeps that would let me know what the stove temperature is. Short and not loud and spaced about every two minutes so they are not "too" annoying.

I would be happy to join others that was interested in fabricating similar devices this winter! I can help with the design.

Email me if you are interested.

regards, Mike

In all seriousness, one of the dual thermocouple devices I listed above is really really close to an ideal stove monitor. Has a high and low temp alarm you can set. My guess, however, is it is probably rather obnoxious as it is intended to be a true "alarm." I'd like one or two beeps to just let me know if I should go check on it, engage cat, reload, etc... They also track the peak temperature ever recorded, which is a nice feature if you want to know whether you stove behaved while you were away. You also have all the data there to integrate how much heat went in the house versus up the chimney so you would learn the optimal air settings over time. Flexible thermocouples with high temp insulation could go anywhere in your system - cat, flue, etc... and are rather cheap.

If I wanted to run a PC near my stove, this would be an easy setup to home build via LabView or similar software, but I don't have the know-how to do that kind of data acquisition and display on a stand alone device that I would build on a breadboard, so I'm looking for something off the shelf a little more sophisticated than the Condar unit. If people are paying that kind of money for the Condar unit, seems like a good market opportunity for something much more elaborate at a similar price point since obviously $100 units do way way more.

-Colin

 

[Kenny1]

Hiya Colin:


How about home brewing something?

If I were going to start a project like this (small run, specialized equipment), I would be temped to find a sutable sensor, then get a BASIC Stamp module ((broken link removed to http://www.parallax.com/html_pages/products/basicstamps/basic_stamps.asp)). BTW, parallax does offer sensors that go to 1873F.

Stamps are easy to interface to displays. They also have serial communications. Me, I'd just provide a 232 port. If someone wanted ethernet, go to black box and get a 232 to ethernet box.

Of course, the starting point would have to be to define the project, including all required features. There is a world of difference between displaying the value from a sensor and logging multiple sensors and providing real time communications.


In the end, it may be cheaper and faster to find a second hand logger that can accept the sensors that you want to use, and has (most) of the features that you require. Maybe modifing an existing model may give you exactly what you want.

I'd like to be more help, but I haven't done an embedded system in over three years (getting pretty rusty). However, if this pellet head can be of any help, please let me know.

Stay warm


Kenny

PS - the thing that would scare me to death about this project is selecting sensors that would be acceptable for the environments in the flue or cat chamber, then writing a manual telling people how to install this 3rd party piece of equipment safely into their stove/flue.

 

[par38lamp]

I thought I had the solution, but then I remembered the price I was quoted. It is a FW Murphy "MDTM89 Dual Temperature Swichgage". It takes two thermocouples, and will alarm on either one at your programmed setpoints. My cost was around $1,200, so no go there. Not very home decor friendly, either...

I had priced this unit to monitor the input and output temps of an oxidation catalyst installed on a diesel generator.

(broken link removed to http://www.fwmurphy.com/products/temperature/mtdm89.htm)

 

[Kenny1]

********** :lol: *********** We will need a special name for this kinda of stove ,
We could call it a ......................... " _ _ _ _ _ _ stove "[/quote]

This is awesome - and the best part that Kenny missed is that we could make this newfangled miniature fuel out of free waste products from wood processing facilities. Then we can charge whatever the market will bear right in step with the skyrocketing price of all other commercial fuels and tell people it's, um, transportation and shipping!

After spending $2-$3K on one of these _ _ _ _ _ _ stoves, you'd be an idiot to not use it, so you gotta keep that thing working, buy that special fuel and tell everyone how much money you're "saving" right?

-Colin[/quote]

Heh heh - you beat me to it! Yeah, we can recycle wood waste!

 

[mikenr1c]

Kenny and Colin:

This sounds like a fun project. I would like to contribute. If you use the BASIC Stamp (or something like it) it could cost up to $100. If you decide to go with a wired solution it would be less, maybe $30 +/-. Of course a lot depends on the feature set.

I could be flexible - if you guys thought a BASIC stamp was the best approach I would be happy to go along.

Regards, Mike

 

[MikeS]

i am starting to learn to operate my cat jotul 8. after I know how to work it, I may lose interest in these measurements. Part of the idea is to be "retro" and I don't know how much interest i will have in the temps after I learn the "timing." By timing, I am learning how long it takes to get the box hot, etc.

One thing I would consider, though, is automatic or partial setting on cat damper. it is hard to get a big enough fire when bypassed so that when the cat damper is switch that it doesn't smolder. if I manually close the cat damper most of the way, i can transition slowly and it works better.

Again, it is probably timing and I will learn as time goes on. but I have been thinking about a wedge for the control handle that would hold the cat damper slightly bypassed for a few minutes so I can get hot gas into the cat without slowing down the fire too much.

Waiting for the whole iron box to heat through conduction to the point where the cat is close to light-off is tediuos, where heating through convection with even a little hot exhaust is much faster--expecially considering that the cat in my stove is in the bottom back--there are several pieces of casting that have to get hot through conduction/radiation to warm the cat...

but I will learn the tricks and i fear that I will be less interested in the novelty of monitoring once I am pretty good at operating...

But if anyone wants to pursue this, PM me. I have the experience to build these monitors at any level of complexity. I can do the controls for the air and dampers, too, but they won't look pretty. they would look "industrial" so I am not too interested in that. I think my interest would be in a monitor--draft and temperatures with I/O for thermostats and alarms, etc.

 

[velvetfoot]

I think these guys have a pretty good name in the car field.
http://www.spatechnique.com/product_pages/productdetails.asp?product=DG%20210|375

 

[cbrodsky]

For my interest, the #1 useful feature would be to have a monitor unit would be to give one type of beep if you exceed a setpoint for engaging the catalyst.

#2 would be a different sounding overfire beep to let you know you should back off the air feed.

#3 would be flue temp upper/lower alert so you know if you're drawing more air than necessary to get the fire going, or not enough to really keep the flue up to temp.

#4 would be a peak temperature memory for both temps as a check for those that burn the stoves away from home that the stove didn't do anything unanticipated.

#5 would be logging - nice, but a lot more complexity and most people would never use it.

I think we all learn these things over time and get somewhat close on the timing and settings, but the reality is every load of wood varies, as does draft and environmetal conditions. Some nights I'm amazed how fast it gets up to temp and others it seems to take much longer. A couple temperature readouts with audible alerts for the key things that can happen in a wood stove that might motivate some adjustment by the user would tell me the perfect time to get up off the couch and make an adjustment, thus letting you squeeze a little more efficiency out of your stove and wood supply.

-Colin

 

[MikeS]

ok: i haven't been burning long enough to realize differences in loads and environmental conditions. I will keep it in mind.

 

[MikeS]

this can do it for $300. (without audible alarms)

(broken link removed to http://www.omega.com/pptst/iTCX.html#tc)