Stove top temp VS stove pipe temp

[bbc557ci]

I started a smallish fire this AM. Used a bunch of kindling, mainly 2" stuff and added a small-medium split about 1 1/2 x 6. I let the fire get going, then as always shut the air supply down. Not allot of wood/fuel to begin with. Just wanted to take the chill off, and did

Now the stove top thermo reads about 650, and the thermo on the stove pipe (+,- 18 inches above top of stove) reads 225-250. I'm wondering about creosote build up, with the pipe temp so low. However, as the stove/fire box temps are still high, I would think that the gases/debris that turn into creosote would be pretty well burned off, before they get a chance to enter the pipe.

Question is.... will this type of burn cause or encourage, or lead to creosote build up? Both thermo's are Condars.

fyi..... Stove is a PE Alderlea, pipe is about 20 feet straight up through the roof.

Whatch'a think??

 

[begreen]

400 sounds about right for what I would be reading on the probe thermometer with the stove top at 650.

 

[Todd]

That sounds ok to me. If the stove pipe drops off any lower and you see a lot of smoke out the chimney give it more air.

 

[Highbeam]

Is this a probe thermometer on the flue? If so, you are doing exactly what you shoudln't be doing. Sending cold flue gasses up your flue. The normal range on that condar should indicate a temp of 400-900 or so right? With below 400 being the creosote forming range. regardless of stove top temp, the water is being burnt off of your wood and will condense in the flue if you keep it too cold.

I'm a new probe meter owner and this is the exact reason I bought a probe meter.

If you are reading surface temps with a mag meter on the flue then everything is different.

 

[Todd]

I was thinking it must be a magnetic external temp for that low of temps. Highbeam, let me know what your internal flue temps are this year, I'd like to see if there are any differences in cat and non cat flue temps.

 

[bbc557ci]

Is this a probe thermometer on the flue? If so, you are doing exactly what you shoudln't be doing. Sending cold flue gasses up your flue. The normal range on that condar should indicate a temp of 400-900 or so right? With below 400 being the creosote forming range. regardless of stove top temp, the water is being burnt off of your wood and will condense in the flue if you keep it too cold.

I'm a new probe meter owner and this is the exact reason I bought a probe meter.

If you are reading surface temps with a mag meter on the flue then everything is different.

Yup, it is a magnetic thermometer on the pipe. Initially when I shut down the air supply the thermo on the pipe was at around 525-550 and stove top was about 700-750*. Small fire... the fuel consisted of 7-8 good sized kindling with 1 split about 2 x 6 on top. Fire had been going for quite a while and had burned down allot when I posted. But when I did post, stove temps were 650ish, and pipe was about 225-250.

I like the idea of a probe thermo. When I get the pipe hot enough the magnetic thermo will loose its grip and actually slide down the pipe. Any advice on what brand of probe, or where to look for one?? Thanks!!

 

[Highbeam]

I've only owned the one probe meter and only for the last month or so but like your other meters, my probe is a condar. Seems to be the most common and one of the only brands available. I actually called their office and asked a tech question and talked to a real person that gave more than enough info. You can buy directly from condar or I bought mine from ventingpipe.com

So far I can easily get my flue temps to 800. 900 with some effort and then they tend to cruise around 600 with the shoulder season type burning I've been doing. I give plenty of air to a small wood load just to heat the stone. I'm not sure what temp my flue will run with the primary air cut back. I'm surprised at how steady the flue temps are, with pretty slow reaction times.

 

[madison]

Is it double wall pipe off the top of the T6 that the magnetic thermometer is stuck to? If yes, the measured value would be very false low.

Begreen posted a spreadsheet with his stovetop and stack temps a cpl yrs ago which may help you out.

 

[bbc557ci]

madison - Pipe coming off the stove is single wall. There is a bit of a gap between the body of the thermometer and the pipe, as the magnet protrudes out from the body of the thermometer, maybe 1/16 in. or so. Of course the gap increases due to the shape, or circumference of the pipe itself. I doubt of these types of thermometers are really accurate to begin with. Then throw in a gap here or there, and consider location of the thermo, God only knows what yer gonna come up with LOL

Highbeam - Thanks for the info on the probe type. I'll check out the source / site you mentioned, as I would like to pick one up. Might pick up a hand held infa-red (spelling??) as well. That would be nice to have for the stove and I could also put it to good use monitoring oil temps of my boat engine

Thanks for the input and info everyone. It's much appreciated.

 

[begreen]

Here's a snippet from the old post that will give you an idea of stovetop vs probe thermometer in the stack. This is burning softwood, YMMV:

8am: start stove from cold, establish coal bed
10am: add full load of wood onto coal bed, stove top at 600 degrees
11am: stovetop @650, stack @500 (air control is all the way closed)
11:30am: use poker to move wood closer together. Within 5 minutes 675 stove top, 400 stack
1:30pm: 550 stovetop, 300 stack
2:30pm: 450 stovetop, 250 stack
4:30pm: 300 stovetop, 150 stack

4:30pm: Add wood - 3 splits
4:45pm: turn air control all the way down
5:00pm: 500 stovetop, 400 stack, serious secondary burning
11:30pm: 550 stovetop, 325 stack, wood about 2/3’d burned, but going strong
2:00am: unknown, but stove still hot and heating
7:00am: stove warm, maybe 110F, enough live coals for easy restart

 

[bbc557ci]

Thanks BeGreen!! What type/brand of probe thermometer are you using??

For the record.... When I had the chimney cleaned after the last burn season the sweep got about 1/2 to 3/4 of a small coffee can of crap out of the chimney. So I'm confident that the way I'm burning or should I say the way the T6 is burning, all is well. I just wanna keep it that way ;-)

 

[begreen]

Condar.

 

[bbc557ci]

Condar.

Thanks again...