
12/12/09, 07:47 PM
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Join Date: Oct 2004
Location: Western WA
Posts: 4,729
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Quote:
Originally Posted by Cabin Fever
Let's get technical here. The desired optimum temp is 300ºF at the point where the wood smoke is exiting the chimney. So, in your situation you might want to consider putting a thermomter on your double wall pipe while someone is up on the roof monitoring the temp of the woodburning gases as they exit your chimney. When the guy on the roof says the temp is 300ºF, read the temp on your stovepipe thermometer (for instance it might say 200ºF). What you want to do from then on out is make sure that the stovepipe thermometer always reads 200ºF or more.
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It's interesting how much the gases cool on their way up the pipe. My shop wood stove has 6" single wall pipe, 12.5' long inside, and then another 5' of insulated stainless pipe exterior above the roofline.
Max temp on the stove top is 500-550* near the collar. 330* @ 3' of pipe, 287* @ 6' of pipe, 256* @ 9', and 200* @ 12.5' where it enters the ceiling box and transitions to the exterior insulated pipe. Of course all the heat off the single wall interior pipe helps to heat the space. Just for kicks I've tried to get the temp where the smoke is exiting the insulated exterior pipe using the laser from ground level but no joy. Of course the outside of the insulated exterior pipe is cold (as it should be) @ 26*, and I tried to aim the laser at the underside of the cap thinking there would be some heat there but it was cold as well @ 31*. There is no visible smoke, just the visible heat signature ,and I guess to get an accurate reading 'somebody' would need to get on the roof and put a prob in the air current where it exits the pipe just under the cap.
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