The Danger of Heat Spikes and Stove Temps

[mikepinto65]

For folks who don't recall/use this trick. A while ago someone (sorry, I don't recall who) on this forum made a really good suggestion on how to know what the peak temperature your stove hit while you were away from it if you are using a stove top thermometer. I've been using it ever since and it is simple and very low cost...

Simply take a piece of foil and fold it so that you have a small V shaped piece and place it in the groove of the thermometer on top of your stove ahead of the needle. Make this foil small and light enough to be easily pushed by the needle as the temps rise, but heavy enough to not be easily blown off (i.e. more than one thickness is my suggestion). Then before you leave the stove gently nudge it against the needle so that as the temps rise it will push the foil up. When the temps go down it leaves the foil at the 'high temp' mark and you will know what it was.

Anyway - using this method you can know what the peak temp was on your overnight/day burns. Clearly you won't know when or how long that peak temp was. But it can be interesting to know if you are peaking higher than you expect.

My experience with my VC was that it would peak much higher than I expected many nights and I was unable to predict when/why etc (part of why I lost confidence in the stove).

With my current FV I have found that it tends to peak early on and then stay pretty steady with a slow rise for the first hour or so. Like someone else posted I did find that I would get a second peak/spike about an hour or so after feeding when I was using less well dried wood. Then again last year was my first year burning with it and my wood was VERY mixed so things were changing constantly between my experimenting to try and figure out how best to burn and the variability in the wood I'm not sure I really had a predictable pattern. But in any case I never saw any high temperature peaks that alarmed me.

I already beat you too it Slow1 :snake: :roll:

 

[Slow1]

Heh - guess that's what I get for not reading every part of all the posts eh?

Well, it still is a good idea eh? and yes, I have earned my name many more times than you know!

 

[Todd]

The only time I get a heat spike with my cat stove is if I cut the air down too much too soon. I've seen my stove top jump up to 750 with a black fire box and glowing red hot cat. I think if conditions are just right the cat gets smoke overload and can really get cookin. I've been told the cat can take those temps but the cast iron doesn't like internal temps over 1400 which is about double the external stove top temps. So I find if I leave a little red coal and flame in the box the stove will peak in about an hour, hold temp and gradually decrease.

 

[soupy1957]

BattenKiller: You said "Stove top temps that high on any portion of the top ........" My readings are from my Rutland, on the front flange. Look at an illustration of an Avalon Rainier 90, and note the overhang that is on the front face of the stove. That's where my Rutland lives.
Originally, when I bought the Rutland, I had it on the TOP of the stove, and was told that I should put it on the overhanging front flange for a more "accurate" reading. The temperature readings I'm getting from the front flange overhang are about 100ºF hotter than what the Rutland was reading when it was on TOP of the stove.

Jake: You said ".....catching nearby combustibles on fire if they are too close,......." Let's clarify that, in case there are any newbies in here reading it. In order for nearby objects to combust, they would have to reach a minimum of 450ºF (or so someone in here told me in another thread). So when you are talking about things catching fire, you're talking (I presume) about hot ashes that escape and land on nearby combustible objects.

Branchburner: You said, ".....there is a point at which the balance of primary/secondary combustion hits another “sweet spot.” " This usually comes when the wood, now breaking down, collapses from its original position, into a pile, flaring up the flames a bit.

BattemKiller: You said, ".....otherwise known as “Pee-thirty” in the morning." I know that time of night very well!! A good opportunity to check the fire, I dare say!

Would a secondary spiking in the temp be MORE likely or LESS likely if my damper is fully open (understanding of course, that if my damper is fully open, I'm wasting heat up the chimney, .........but that aside........)?

I like that idea with the tin foil, .......I think I'll try it!! Either that, or I could set up my video camera to record all night...........naw........scratch that...........don't want my camera to melt.........lolol.

-Soupy1957

 

[mikepinto65]

Basically what all this means to me is the following:

http://www.youtube.com/autotunethenews#p/u/9/MX0D4oZwCsA


............sorry, probably showing how immature I really am with this one. (although they do have some very funny stuff and im SURE everyone here at hearth.com will get the T-Pain referencing in all the songs.....let alone know the now stupidly famous double rainbow video......)

But really though, as the video shows, some things just cant be explained.

 

[firefighterjake]

. . .

Jake: You said ".....catching nearby combustibles on fire if they are too close,......." Let's clarify that, in case there are any newbies in here reading it. In order for nearby objects to combust, they would have to reach a minimum of 450ºF (or so someone in here told me in another thread). So when you are talking about things catching fire, you're talking (I presume) about hot ashes that escape and land on nearby combustible objects.

. . .-Soupy1957

Mostly yes . . . concern over hot coals escaping . . . although there is some concern over time with combustible items being too close and having pyrolysis take place . . . and then there are the folks in the "Just Plain Dumb" category who bring their chainsaw inside (filled with gas) and place it just a few inches away from their woodstove so it will start easier in the morning . . . and yeah . . . I saw a fire started that way!

 

[soupy1957]

Chainsaw left near the woodstove? Really? How "braindead" is THAT!! Geez!!

-Soupy1957

 

[BrowningBAR]

I'm baffled as I never noticed any on the old stove or the new one (only 2 months with the summit) but I will keep an eye out this winter.

And you being baffled baffles me as it is clear to me that the old Vigilant spikes throughout it's burn cycle.

 

[begreen]

Our old Resolute would swing in temperature also due to it's thermostatic control. The oscillation would be larger at the beginning of the burn than towards the end.