Thermometer Advice

My Surdiac has a heat exchanger on the back, and appears to be the only place to put a thermometer. With the exception of the stove pipe, everywhere else is covered in tin. I was given a rectangular thermo. with a bi-metallic spring behind it, with a couple small studs to mount it.Currently, it just rests on the top of the exchanger. (Not impeding the function of the spring) The readings range from 200*-600* and most times appear to be responsive. This yr, my stove is running normal, and the temp is only reading about 350-400. I know it's tough to judge with-out seeing it yourself, but my question is...What is the best place to put a thermometer, and are there any better ones to use? I haven't seen any threads pertaining to this subject and was looking for a little incite from the masters. Thanx.

Every stove is different. Mine is an old Herald Oak No. 18 and it's a cast iron base and fire pot and then a steel barrel with the flue pipe connection in the back. Since I don't have any heat shields, I put mine to the right of the flue. I also use an infrared and aim it at the stack to see what temps are. I used it all the time to see combustion chamber temps when working on engines. It's handy. Once I get it up and running, I like to check it every so often to make sure that my stack temps aren't too high. The only challenge you have is that it sounds like you have a heat shield all around he stove and your putting your temp gauge in the only spot you can. Coal stoves can run at higher heat ranges than wood stoves can. The one thing to keep in mind is that if your too aggressively shaking the grates and not keeping the ash to protect the grates you can warp or burn up the grates. 300-550 is a good range. I think that 375-425-50 is the best range as I get extremely long burn times and still heat the house. Your temp readings are fine, but the real answer is, if your house is comfortable then that's the range. You'll have to run the stove a little hotter in the dead of winter.

i have a threaded probe thermometer that is for barbeque's screwed into my flue pipe. I think this is the third year for it, the probe is still in good shape, I thought it might disintegrate from the coal ash after a year, but it didn't.

joeq wrote:My Surdiac has a heat exchanger on the back, and appears to be the only place to put a thermometer.

That's a reasonable place to put it. You're right that you would not want to place it on the outer shell.

Most folks use a magnetic stick-on thermometer somewhere on the stove body, and another one on the stove pipe. Some spots on the stove are hotter than other spots, but just pick a spot where it is easy to see. The particular temperature is not that important, just useful to compare one time to the next. For example, from experience I know that on a typical winter night 450 degrees is about right for my house, or 650 degrees if it's going to be REALLY cold. If I moved the thermometer to a cooler or hotter spot on the stove, I'd have to start learning all over again.

A probe thermometer can be used on the stovepipe, but IMHO it is overkill. A magnetic one can be easily moved around to different pipe locations, or moved to the stove itself. My rule of thumb is, the gas temperature as measured by a probe will be about 1.8 times the surface temperature shown by the magnetic. And as long as the chimney is drafting properly, the stove is burning well, and flue temperature is not excessively low or high, that's close enough.

Magnetic thermometers, aye. And they'll hold up to the heat? I'ld like to have one on my stove pipe, but where would be a better place to attach it" Before the MPD, or after?

joeq wrote:Magnetic thermometers, aye. And they'll hold up to the heat? I'ld like to have one on my stove pipe, but where would be a better place to attach it" Before the MPD, or after?

Go to Amazon and type in "magnetic stovepipe thermometer". I have never had one fall off the pipe due to magnet failure, even at the much higher temperatures when burning wood. Attach it wherever is convenient -- preferably 18 or 24 inches from the stove. Note that the "combustion zones" or "too cold / just right / too hot" zones on the thermometer are relevant to wood burning, not to coal.

I don't have that much pipe behind my stove Nort. barely 10". and my MPD is less than that, as you can see in my pic. You can also see the thermometer on top of the exchanger. but I think I will pick up one of them there magnetic ones, and give it a try. Couldn't hurt, right?

At around 1,000 degrees, a magnet will loose it's property and fall off a stove. Emery, from the Stove Hospital, said that a few times his stove got going and he'd hear clink, look over and the magnet temp fell off the side of the stove and then he shut it down and as the temp cooled, about 100 degrees, he'd put the magnet back on. He said wasn't trying to do that but got busy in the shop while getting the stove up and running. I'd put one anywhere directly on the stove you can and also add one as close to the entrance to the wall after the mpd. The idea is to see if your letting too much heat up the chimney.

are you saying the black pipe actually gets upwards of 1000*?

joeq wrote:are you saying the black pipe actually gets upwards of 1000*?

100 to 300 degrees is more like it for the pipe.
I suggest the first place you put the magnetic thermometer, is on that fire extinguisher in the corner. I'm not at all sure that is supposed to be heated.

Thanx for your concern with the extinquisher, but it's far enuff away, it's not even warm to the touch.(as you can see the distance in this photo...altho it's not there, you get the idea.)

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