Chimney thermometer-how long do you trust it?

I've got a chimney thermometer that is 3 years old and I'm concerned about its accuracy. It's after all just a spring and needle. Well should I ever have trusted it? LOL
I do pay attention to it, and I'm unsure how long to believe what it tells me. They are, in the grand scheme of things, inexpensive but I'm now questioning if there's a better way that I should be keeping an eye on my flue temp.'s. I try to keep a good eye ensuring my flue is plenty warm. I'd rather waste a bit of wood as I continue to learn the stove and burning rather than risk chimney issues. I am on the "three year plan" but still worry. It's what I do!! Wood is 17% MC at the worst for this season.
I got about two cups of soot from the chimney when it was cleaned before I used it. Didn't seem like anything to worry about but...
Thoughts from my fellow FHC kin? Just keep doing what I'm doing and get a new thermometer?
Thanks!

 

Sounds to me like you have no need to worriy. Burn on!
I look at these mag therms as a guide, not an absolute. Most I've used just aren't perfectly accurate. Does it seem to be registering any different than you expect?
If you NEED the peace of mind, get another, but I doubt it's needed.
A couple cups isn't bad at all, but a lot of folks clean the flue at the end of the burn season instead of letting that stuff hang out in the flue all summer.
Not sure it matters for 20 years or more.
Our old flue was still fine when we moved here......oversized and full of fluffy stuff clinging to the inside, but if I'd needed 8" pipe instead of 6", it would have lasted many more years.

 

They are not the most accurate things but they do seem to work for quite a while, even when used over a combustor which regularly sees 1,400 F temperatures. So yours is probably fine.

Not to spend anyone else's money but a digital readout and a thermocouple inserted into the stove pipe works better and much, much faster. This is what I use and it will respond in no more than three seconds with a very accurate measurement showing any change you make to the stove. Some of us use them as high- limit alarms also; I never let my flue gas temp. reach 750F, just to stay below the often stated temp. of 800F and higher to start a creosote fire. I am not sure that that is accurate but it is very easy to stay below it with the stove I have as it has relatively low smoke exit temperatures anyway. A digital readout and thermocouple can be purchased relatively inexpensively, probably around $50 to $75. If you do a search, there are several people on this forum using a single channel K- type thermocouple readout and there are links to where they purchased them. I use a four channel readout / recorder and watch four different places on my own stove as well as record the data so I can see how the stove burned over time when I am not watching it (at night for example). The readout / recorder was something like $150 and each thermocouple is probably $10 to $15 for inexpensive ones.

Brian

 

I just replaced mine after maybe 6 years. There was a definite coorelation between its calibration and the integrity of the probe. When you could see the probe start to wear away it started not reading at the high end.

 

I like having an IR gun as well as the magnetic one on the pipe or the stove. That lets me 1) confirm the other one is working, and 2) take temps on multiple surfaces when checking the stove and pipe.

 

They are just a gauge to give an idea of temps. I've had mine for over 10yrs and it still seems to work properly and reads the same. Once you learn your stove you'll just look at it occasionally.

Sent from my SM-S320VL using Tapatalk

 

I'm still using one that I bought in the early 90's.

Also bought a couple laser thermometers 3-4-5 years ago that I seem to rely on even more. I can check the pipe and the stove top without having to move the magnetic......

 

Are these probe thermometers or magnetic that last decades? I’d be really suspect of a probe thermometer that is so old- assuming more than occasional use. Even the condor manual recommends changing them out every few years. My last one was literally rotting away. The magnetic ones- I have one from the 80s that still measures okay.

 

Yeah, magnetic.

Excellent point about the probe thermometers!

 

Do you have to pull the thermocouple every time you sweep?

 

I do not use any kind of chimney cleaner on the thimble and the smoke pipe from the stove to the thimble never needs cleaning. To clean the thimble, I run a piece of wire (TIG welding wire, SS, with a circle bent into the end) in a small hole in the elbow just in front of the thimble, the use it to slide any debris back into the smoke pipe.

But even removing the thermocouple would only take a few seconds, it is 'threaded' into the smoke pipe about two turns (not really threaded, just that the thin pipe catches on the thermocouple threads and holds it).

Brian

 

I was so impressed with the consistency and durability of the condar flue probe meter after a decade of use that I bought a new cat probe meter from them, and two inferno surface meters from them. The finish on the dial is in great shape too.

I do have some noticeable deterioration of the actual probe part that extends into the flue. In that corrosive environment that probe will slowly erode. I think it's made of copper or brass. Not sure. It lasts a long time! and yes, I monitor that flue meter a lot since it is visible from the couch!

 

Mine is the magnetic type, also.

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You can just toss the magnetic ones in your oven, set the temp, and see how it compares. I don’t know what Flatlander Pete has for sure, but he put up a picture of a probe thermometer.

 

Thanks for all the input! I appreciate it for sure. My stove has a surround with a blower and my chimney is double wall all the way up. That being said I can't put a magnet thermometer on anything that'll be accurate. I don't trust myself with just looking at the way the fire is burning or the appearance of the secondary's so I do keep a descent eye on the probe thermometer.(mainly at the beginning of a burn)
For now at least, I think I'll get another just to compare readings. I hope that in time I'll be comfortable with my eyes and experience as the way to go. Not quite there yet.
Thanks again Everyone!!

 

A little sideways thought here but I have always found woodstoves easy to use if they are pushed to at least 'medium' or pushed harder. All the trouble and difficulty comes when trying to run them at lower settings and going for a long, even burn. That is when the stove is much more likely to start making creosote, have a combustor stall and so forth. And this 'low and slow' is really only possible with airtight stoves anyway, something like a pot bellied stove just runs hot and therefore, usually quite clean. Of course they run out of fuel in a couple of hours without attention too.

So I think the need for thermometers, paying close attention and really learning the finer points of using a wood stove in each different situation and setup (chimney, stove type, etc.) is only important if trying to squeeze the most efficiency out of a stove when running relatively slowly. Otherwise burning wood is basically setting the draft somewhere like 1/2 open and throwing wood at it; it will run hot enough that all will be well if the wood is reasonably dry and ready to burn.... and it will still run pretty good if the wood in not 100% ready too.

Brian

 

Bu...bu...but eeeeking out that last 10% efficiency is where all the FUN IS!

I watch my temps all the time. I could run the stove without them but now I know how much I would be losing. Also it helps to have something to distract me through the long boring winter.
I upgraded finally to a cat probe this week so, more fun.

 

Oh yeah, I too am all about the last 3%; I am the guy with the four probes (Easy Boys!) and the recording device.

I was just mentioning that there are all different ways to burn wood, and a lot (most maybe?) people just kind of pick a draft opening and toss wood in the big hole behind the door. The opposite end, where people weigh wood, time things, measure multiple temperatures and watch the smoke output carefully, and do everything to keep a domicile warm but not too hot are on the other end of the scale. Personally, I find it a humiliating loss if one has to open a door or window at any point and see that as a 'stove management' failure.

So I was not suggesting anyone be sloppy or careless burning wood, merely stating that it can, and often is, done with a lot less care and effort than reading a forum like this one might indicate, especially to someone new to burning wood.

Brian

 

Keep it cool enough so no parts glow and warm enough that smoke isn't visible. I suppose.

 

I used to wonder why people would heat up a place too much, and then open windows, until I became one one of them. If that's all it takes for you to feel like a failure, I'd sure hate to be stuck in your head.

Is your weather forecast never wrong there?