Pegging the needle

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ddug

ddug

New Member
Nov 26, 2010
55
SW New Mexico
I'm pretty new to wood stove burning and still trying to figure out what is right as far as temperatures are concerned.

I have a thermometer about 18 inches above my little VC Aspen mounted on single wall stove pipe, and with the fire burning nicely I usually see temperature readings about 400 degrees. I have had it spike to 700 degrees on several occasions and am still trying to figure out how to control that better.

So just for giggles last night I put the thermometer on the stove top because I was curious about the temps there. I had what I consider an average fire going and the flue temp was about 450 degrees. The thermometer I have goes to 850 and when I put it on the stove top the needle was soon pegged at maximum. I don't think it was too far beyond that as it (the temp dial) was slowing down considerably by the time it reached the upper limit.

From what I have learned here that seems pretty hot, and I was surprised at the discrepancy between the flue reading and the stove top reading. Makes me wonder what the temps must have been when the flue was at 700! I haven't seen anything glowing yet.

Am I hurting this stove?
 
If your flue thermometer is magnetic, and not probe, you're not measuring the flue gas temp, which is much higher than the pipe surface. Others can comment on the ratio...
 
I thought a magnetic thermometer was the correct way to measure the flue temperature on single wall pipe. No?
 
ddug, just this morning our stove top reached 700 degrees. The flue temperature reached 400. This is maximum for our stove.

Probably a more normal burn would have our stove top in the 500-600 range and the flue close to 350 but I have seen 500 vs. just a tad below 300. Our chimney stays nice and clean but then we also have very dry wood too. Our stove has a cat so there can be some differences in temperature ranges but not a great difference. With any stove, it would certainly concentrate my attention once it got to 800 stove top!

btw, our flue temperature we let go to 500 on reloads. Then we turn the draft down and that temperature settles back in the 300-350 range quite rapidly.

I hope this helps.
 
On reloads I see flue temps up around 600, stove top around 650-700. Once the stove settles in, usually have a stove top of 450-550 and flue temps of 280-300. I too have single wall pipe and am using a magnetic thermometer.

One thing to keep in mind- I just bought a new magnetic thermometer and was getting readings about 150 degrees higher than my old thermometer- it may be possible that your magnetic thermometer is giving you high readings. I plan on purchasing an IR thermometer to try and figure out which is right, so for now, I am taking the average between the two.
 
This style stove can get hot quickly. With a fresh charge of wood, there can be quite a bit of wood gas released, especially if the wood is put on a hot coal bed. 700°F is pretty hot for surface flue temp. You don't want it to stay there for long. Try letting the fire die down a little more before reloading if this is the case.

Is the air control fully closed when you got these readings? Reading back it looks like this is a 22' flue, correct? You might want to try a pipe damper to slow it down a little bit during the coldest weather.
 
Is the air control fully closed when you got these readings?
Click to expand...

Not quite. Last night was the first time I took a stove top reading and it was about an hour from lighting the stove from a cold start. This stove has a thermostatically controlled air control that I'm still trying to figure out whether or not I have adjusted right. Overall it works pretty well and gradually closes down as it heats up, but you don't really have full control over it. When the stove is cold you can not completely close it down, and when hot it can not be fully open.

Reading back it looks like this is a 22’ flue, correct? You might want to try a pipe damper to slow it down a little bit during the coldest weather.
Click to expand...

Yes, that's right. I was thinking of a damper but I'll probably hold off until next season and in the meantime get to know this stove a little better.

I am going to get a stove top thermometer so I can see what's going on a little better as far as flue temps vs. stove top temps. I've been happily running this thing with flue temps normally running between 300 to 500 degrees and had no idea that the stove top may have been running that hot.
 
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