Steam out of chimney,,,,,why?

[Black Jaque Janaviac]

You guys say this steam should dissipate within a few feet, but I find the opposite sometimes. And it has me bugged, because now I’m thinking there could be some smoke in there also.
This morning temp. was about 18*. My breath fogged and trailed several feet behind me, the car exhaust filled the driveway with a noxious fog, and my flue had about 20 foot of steam (?) trailing over the yard. Is that possible?
Pipe probe temps. were around 700* at the time. Combuster was doing its job, or so I am thinking.

Is this steam business relative to flue temps and wood moisture? I’ve seen furnace exhausts on homes really pouring out the steam in certain weather conditions.

The size of the visible plume of steam is going to depend on the flue temp, exhaust flow, moisture content of the wood, AND weather conditions.

If you see a bluish tint to your exhaust then you've got smoke. I wouldn't worry about just steam. More germain to excess wood moisture is probably blackened viewing glass.

You can gauge how much of the plume is due to weather conditions by doing just what you did - compare to other steam sources. If your breath leaves a long, lingering plume of white steam then expect your chimney to have a longer plume also. However, if you breath cloud dissipates quickly then you can expect to see the chimney steam do the same.

 

[Troutchaser]

It makes sense to me that I would have a steam trail out my flue on a morning like this morning.
I just never hear anything on this site other than. . . . if it dissipates within a few feet, it's steam. Maybe that's for daylight hours.

Glass is staying nice and clean.

 

[Black Jaque Janaviac]

Well, I live in a papermill town and most of what belches out of those stacks is steam and that certainly doesn't dissipate within a few feet. However, it is easy to note differences between low humidity days and high humidity days.

Again, watch the glass, and sweep the chimney and gauge things based on creosote build up.