Smoke coming from my 90 deg elbow?

[Josh Hufford]

Sorry for the bad pic but I just grabbed an image with my phone when I saw this happening. Smoke was leaking out of the joints of the elbow. What would cause this? Just a bad elbow? Should I replace it? It doesn't happen all the time but I see it happen sometimes. And it isn't paint burning off or anything it is wood smoke for sure.

Thanks!

 

[Prof]

I'd be concerned about a blockage in the chimney/pipe--especially if this is a new event. Was there anything unusual about weather conditions (i.e. high winds)?

 

[Josh Hufford]

I've seen this one both a breezy and calm day.

 

[raybonz]

Look for a blocked chimney or cap as this will cause this..

Ray

 

[BobUrban]

Warm temps or heavy wet weather or a combination of both could cause poor draw. Is there any upward angle to the vertical pipe?

Look into it - there is a cause and a solution but more evidence is needed for the forum to offer the ladder.

 

[DanCorcoran]

Denser, cooler air in the room should be pushing its way into the stove and the flue, as the hotter, lighter air in the stove and the flue rises, creating a partial vacuum. If smoke is coming out of the flue, instead of room air pushing its way in, then you have poor draft. Could be any of several reasons, as noted above.

 

[stoveguy2esw]

was this at startup from a cold fire? sometimes when starting up with a cooler chimney (especially if its not frigid outside) the "standby" draw (the slight bit of draft in a cooler flue from the moderately warmer air in the home) may not be strong enough to pull the smoke out as fast as it is created.

think of it this way, the dynamics of a flue in a cold start, the highest temps are at the fire, the air is lighter and hotter so it rises quickly, the cooler air above it creates a "plug" which causes higher pressure below the cold air plug, this forces the hotter air out through leaks in the elbow.

a "hot reload' is much less likely to do this as the flue is preheated and the cold air plug is not present.

how old is the pipe (elbow)? connector pipe should be replaced periodically as it does degrade over time.elbows tend to develop leaks over time due to the "joints" in the elbow being "worked" by expansion/contraction from heating up and cooling especially segmented elbows (adjustable elbows) as they are not single pieces of steel.

 

[begreen]

Just a guess. Mild temps + short chimney? Or, when was the last time the chimney and cap were cleaned?

 

[Josh Hufford]

Thanks everyone for the great info. There horizontal part is level, no rise. I've seen this happen twice, I don't remember the exact burning conditions now but I do know it was not at the start of a burn. All of the piping was installed 12-13-12, it has not been cleaned since it was installed, I do however plan on taking it all apart and cleaning it at some point this summer, I'm done burning for the year anyway, were getting a lot warmer weather now.

 

[mellow]

My 2 cents, you have created a mini cyclone in that pipe, it is hanging out right at that bend due to bad draft and it is just swirling around while waiting for it to be sucked up further, it will look for the path of least resistance.