Secondary burn furnace exhaust temps

[Ozark Woodburner]

I just installed a Napoleon HMF furnace that is a secondary burn furnace. I have only had a couple fires at this point, but I have noticed the flue does not get nearly as hot as a wood stove. Even with a roaring fire I can only get 275 degrees on the surface and it is normally 150-250 degrees. Is this normal? I do not have a probe installed but do have a simple magnetic gauge on the single wall pipe 1 behind the furnace.

Otherwise, this thing is awesome. I cannot believe the amount of wood, or lack of wood that I'm burning.

 

[laynes69]

Yup, perfectly normal. I've been curious to hear from a user of that furnace. It's setup like our caddy, but a few more options. I find our flue temps are about the same as what your reading. 250 external is a very hot furnace. What did you have prior? I also was surprised with the lack wood ours used. Did you choose a glass door or insulated?

 

[Ozark Woodburner]

I had an older wood stove prior. I got the glass door with mine. Watching that secondary burn work is awesome and I thought you had to have a roaring fire for that to happen but that is not the case. Three small sticks are lasting 10+ hours in mild weather (mid 30s at night, 60s during the day). The heat coming off this thing after the fire has burnt out is what impresses me.

 

[laynes69]

Thats awesome, you'll have to keep us updated.