Relationship between magnetic surface temp and internal flue temp

[ikessky]

I've read a couple different things regarding this issue. So what is the right answer? If I'm using a magnetic temp gauge on the stove pipe, do I have to add 100-200 degrees or double the reading to see what the internal temp actually is?

The reason I ask this is because last night, the thermometer showed 200-250, but the fire had some lazy flames and was producing very little smoke when the door was opened (sorry, I don't have a glass door).

 

[begreen]

You can double the surface flue temps for a rough approximation of the interior flue gas temp. Once the wood has gassed off and is in the coaling stage, there is very little smoke produced, though it can still be producing a lot of heat.

 

[ikessky]

So it is before the coaling stage, when the wood is gassing off, that the real potential for creosote is present?

From what I have been reading/hearing, running my wood furnace with a magnetic temp of 200-250 should be just fine then.

 

[begreen]

Depends on the flue. If it heads outdoors and has a long cold run, the flue gas temps can be well below 250 when the gases leave the cap. If that is so, you might want to run at 3-400 during the outgasing stage.

 

[ikessky]

The chimney runs right through the center of the house. Masonary chimney with clay liner and I added a 316ti liner inside of that. I'll burn for a month or so and then sweep the chimney and see what it looks like. I did pull out the stove pipe and it doesn't look any worse than last time, so I think I'm doing it correctly now.