I hate to admit this but I need to know...

[mfglickman]

I've been here almost a year, I've read the Hearth.com articles about EPA, non-EPA, CAT and non-CAT stoves...but can someone please tell me what it means when people talk about all the "secondaries" they can see in the firebox? What does that mean?

Thanks!

 

[Slow1]

The "Primary" burn is the fire on the wood itself. The "Secondary" burn is when the smoke is burned. Generally when folks are referring to seeing the secondaries burn they are referring to what they see near the "burn tubes" in a non-cat stove. These 'burn tubes' bring air (oxygen being the important part) into the stove and generally heat it up on the way - by injecting this hot air into the already hot smoke it burns the smoke and can make for quite a show. More importantly, this is burning off the smoke to get the energy out of it and cleaning up the exhaust at the same time.

Cat stoves also have a secondary burn - but it is in/around the cat most of the time and not visible.

You don't have to have injection of air at tubes or be near the cat to have secondary burns either - sometimes you just get the smoke happily burning in a hot firebox where ever the optimal heat/oxygen/smoke conditions exist.

 

[blujacket]

Post# 8

https://www.hearth.com/talk/threads/secondaries-flame-only.90721/#post-1185483

 

[etiger2007]

In the top of our non cat stoves there are tubes with holes in them that run east and west in firebox ( three or four tubes depending on make and size), these tubes reburn the smoke for a clean burn, and in doing so when the fire is hot enough to " ignite the secondaries" it makes quite the flame show. It looks kinda like the burners on you BBQ grill when lit for lack of a better discription.

 

[Billybonfire]

Secondaries refer to the flames coming from the tiny holes at the back of the firebox above the fuel level.
This is caused by supplying heated air to the gasses coming off the wood which then ignites, these gasses would otherwise be wasted energy going up the flue.
I like the term "afterburners"

 

[FyreBug]

clink on this link... then click on the "how it's made" video link. It was filmed as part of the series on the Discovery Channel to explain how a stove works.

And the link is not a gratutious link to products, I use to have this video on my Youtube account but had to remove it due to copyright issues.

 

[Blue2ndaries]

Thanks for the link FyreBug, that's a very informative vid.

 

[mfglickman]

Thanks all!

 

[ridemgis]

Have a look at this:

 

[etiger2007]

clink on this link... then click on the "how it's made" video link. It was filmed as part of the series on the Discovery Channel to explain how a stove works.

And the link is not a gratutious link to products, I use to have this video on my Youtube account but had to remove it due to copyright issues.

Great video FyreBug

 

[corey21]

This brings something to my mind does a big secondary fire eat threw wood real fast compared to a stove just picking off what the wood fire missed?

 

[certified106]

This brings something to my mind does a big secondary fire eat threw wood real fast compared to a stove just picking off what the wood fire missed?

In my opinion yes, I always aim for a fire with a few flames coming off the logs and wisping secondaries and occasional puffs of secondaries. When it is burning this way it burns much longer and the flue temps stay way lower.
The huge roaring secondaries are a lot of fun to watch but in actuality all you are doing is offgassing the whole load of logs very quickly and just end up with a huge coal bed.

 

[WellSeasoned]

The secondaries pump out soooooo much heat. Its similar to a wall mounted gas heater. I usually see a small line if fire coming up from the wood itself, while the secondaries are pumping, then no fire from wood, just secondaries. We have a non cat stove

 

[Huntindog1]

A way to look at it, if you lower intake air the fire gives off more smoke but if you can maintain the heat level the extra smoke will burn up in the top of the stove.
Its a real tricky balancing act. If your fire box is designed to keep the heat up in the fire box and importantly using very dry wood then the secondaries burning can sustain the heat that sustain the secondaries doing all that at the lowest air setting possible.

 

[Huntindog1]

The secondaries pump out soooooo much heat. Its similar to a wall mounted gas heater. I usually see a small line if fire coming up from the wood itself, while the secondaries are pumping, then no fire from wood, just secondaries. We have a non cat stove

Wellseasoned,

I think you hit on an important point , people are always disappointed with these burn tubes stove when they try and operate them like an old fashioned stove.

As if you dont get these stoves to burn secondary mode you cant get much heat out of them.

As its those secondaries that adds sooooo much heat to the stoves output. Its all about the heat build up in the firebox and getting those secondaries to light off.

More than 20% mositure in the wood keeps this from operating so well.

 

[corey21]

Thanks guys.